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000
FXUS63 KILX 210951
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
351 AM CST Fri Nov 21 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST FRI NOV 21 2014

High pressure ridge over the region this morning with light and
variable winds across Central Illinois.  Another cold day expected
with highs in the low to upper 30s, but some moderation in the
airmass is expected going into the evening  hours. Southeasterly
winds increasing through the afternoon as the ridge axis slips
eastward.  Main issue for the forecast remains the onset of rain
this evening as the temps drop below freezing.  Models are still
changing a bit with the timing of the cold air and the approach of
the precip. Moisture advecting into the region on the back  side of
the ridge building some weak showers north as temperatures drop
after sunset. The window for freezing rain may be short-lived,
particularly along a line from Springfield to Jacksonville. Rain
spreading north into the region before the bulk of the warm air
moves into place and sfc temps will still be at or below freezing at
onset. Also, the ground is still frozen and am concerned that the
warm air will be a little slower to erode the cold dense air at the
sfc. Best chances for the freezing rain will be narrow and variable
windows from  6pm to midnight, shifting northward as the evening
progresses.  The threat will come to an end as the warm air works
its way into Central Illinois.  Some adjustment likely to the
advisory after the morning run of models comes in.  Variation with
every run has resulted in low confidence about the duration of the
freezing rain threat, so there is a bit of a cushion in the timing
of the ice accumulation.  Accumulations are expected to be low, and
in some areas, may see little more than freezing drizzle,
particularly east of the Interstate 55 corridor north of Lincoln,
closer to the drier air under the sfc ridge.  Either way, the first
icing event of the year, regardless of duration, will be issuing an
advisory.  Freezing rain advisory out for the evening hours, ending
before the morning traffic picks up.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 349 AM CST FRI NOV 21 2014

More southerly winds will begin to set up late Friday in advance of
a developing system to the SW. Same developing system will continue
to produce rain through the weekend.  A gap continues to show up in
the models between the developing warm frontal feature and the core
of the sfc low. But the timing is just different enough in the
GFS/NAM/ECMWF to maintain a rather high chance/likely pop through
the overnight Sat night. Best chances for the weekend is in the high
chance/likely category for precip, and has moved to categorical on
Sunday with the highest QPF.  Temps not high enough to significantly
warm the ground, so some frozen ground will increase some threat for
rising creeks and rivers with increased runoff. Beyond tonight,
Saturday through Sun night will be dominated by rain before possibly
seeing some snow on the back side of the system as cold air moves
back in late Sun night/early Monday as the precip comes to an end.
A soggy weekend overall, with temps struggling into the 50s for
Sunday.

Next week will see a return of some cold temps as another trof digs
into the center of the country.  A chance at a clipper system
starting to show up in the model runs for Wednesday, potentially
impacting a busy travel day, and have upped to a chance pop to start
the trend for that system a little earlier than the SuperBlend.


&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY from 9 PM this evening to 4 AM CST
Saturday FOR ILZ027>031-037-038-045.

FREEZING RAIN ADVISORY from 6 PM this evening to 1 AM CST
Saturday FOR ILZ036-040>044-047>051-053.

&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon








000
FXUS63 KILX 210951
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
351 AM CST Fri Nov 21 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST FRI NOV 21 2014

High pressure ridge over the region this morning with light and
variable winds across Central Illinois.  Another cold day expected
with highs in the low to upper 30s, but some moderation in the
airmass is expected going into the evening  hours. Southeasterly
winds increasing through the afternoon as the ridge axis slips
eastward.  Main issue for the forecast remains the onset of rain
this evening as the temps drop below freezing.  Models are still
changing a bit with the timing of the cold air and the approach of
the precip. Moisture advecting into the region on the back  side of
the ridge building some weak showers north as temperatures drop
after sunset. The window for freezing rain may be short-lived,
particularly along a line from Springfield to Jacksonville. Rain
spreading north into the region before the bulk of the warm air
moves into place and sfc temps will still be at or below freezing at
onset. Also, the ground is still frozen and am concerned that the
warm air will be a little slower to erode the cold dense air at the
sfc. Best chances for the freezing rain will be narrow and variable
windows from  6pm to midnight, shifting northward as the evening
progresses.  The threat will come to an end as the warm air works
its way into Central Illinois.  Some adjustment likely to the
advisory after the morning run of models comes in.  Variation with
every run has resulted in low confidence about the duration of the
freezing rain threat, so there is a bit of a cushion in the timing
of the ice accumulation.  Accumulations are expected to be low, and
in some areas, may see little more than freezing drizzle,
particularly east of the Interstate 55 corridor north of Lincoln,
closer to the drier air under the sfc ridge.  Either way, the first
icing event of the year, regardless of duration, will be issuing an
advisory.  Freezing rain advisory out for the evening hours, ending
before the morning traffic picks up.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 349 AM CST FRI NOV 21 2014

More southerly winds will begin to set up late Friday in advance of
a developing system to the SW. Same developing system will continue
to produce rain through the weekend.  A gap continues to show up in
the models between the developing warm frontal feature and the core
of the sfc low. But the timing is just different enough in the
GFS/NAM/ECMWF to maintain a rather high chance/likely pop through
the overnight Sat night. Best chances for the weekend is in the high
chance/likely category for precip, and has moved to categorical on
Sunday with the highest QPF.  Temps not high enough to significantly
warm the ground, so some frozen ground will increase some threat for
rising creeks and rivers with increased runoff. Beyond tonight,
Saturday through Sun night will be dominated by rain before possibly
seeing some snow on the back side of the system as cold air moves
back in late Sun night/early Monday as the precip comes to an end.
A soggy weekend overall, with temps struggling into the 50s for
Sunday.

Next week will see a return of some cold temps as another trof digs
into the center of the country.  A chance at a clipper system
starting to show up in the model runs for Wednesday, potentially
impacting a busy travel day, and have upped to a chance pop to start
the trend for that system a little earlier than the SuperBlend.


&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY from 9 PM this evening to 4 AM CST
Saturday FOR ILZ027>031-037-038-045.

FREEZING RAIN ADVISORY from 6 PM this evening to 1 AM CST
Saturday FOR ILZ036-040>044-047>051-053.

&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon








000
FXUS63 KILX 210951
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
351 AM CST Fri Nov 21 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST FRI NOV 21 2014

High pressure ridge over the region this morning with light and
variable winds across Central Illinois.  Another cold day expected
with highs in the low to upper 30s, but some moderation in the
airmass is expected going into the evening  hours. Southeasterly
winds increasing through the afternoon as the ridge axis slips
eastward.  Main issue for the forecast remains the onset of rain
this evening as the temps drop below freezing.  Models are still
changing a bit with the timing of the cold air and the approach of
the precip. Moisture advecting into the region on the back  side of
the ridge building some weak showers north as temperatures drop
after sunset. The window for freezing rain may be short-lived,
particularly along a line from Springfield to Jacksonville. Rain
spreading north into the region before the bulk of the warm air
moves into place and sfc temps will still be at or below freezing at
onset. Also, the ground is still frozen and am concerned that the
warm air will be a little slower to erode the cold dense air at the
sfc. Best chances for the freezing rain will be narrow and variable
windows from  6pm to midnight, shifting northward as the evening
progresses.  The threat will come to an end as the warm air works
its way into Central Illinois.  Some adjustment likely to the
advisory after the morning run of models comes in.  Variation with
every run has resulted in low confidence about the duration of the
freezing rain threat, so there is a bit of a cushion in the timing
of the ice accumulation.  Accumulations are expected to be low, and
in some areas, may see little more than freezing drizzle,
particularly east of the Interstate 55 corridor north of Lincoln,
closer to the drier air under the sfc ridge.  Either way, the first
icing event of the year, regardless of duration, will be issuing an
advisory.  Freezing rain advisory out for the evening hours, ending
before the morning traffic picks up.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 349 AM CST FRI NOV 21 2014

More southerly winds will begin to set up late Friday in advance of
a developing system to the SW. Same developing system will continue
to produce rain through the weekend.  A gap continues to show up in
the models between the developing warm frontal feature and the core
of the sfc low. But the timing is just different enough in the
GFS/NAM/ECMWF to maintain a rather high chance/likely pop through
the overnight Sat night. Best chances for the weekend is in the high
chance/likely category for precip, and has moved to categorical on
Sunday with the highest QPF.  Temps not high enough to significantly
warm the ground, so some frozen ground will increase some threat for
rising creeks and rivers with increased runoff. Beyond tonight,
Saturday through Sun night will be dominated by rain before possibly
seeing some snow on the back side of the system as cold air moves
back in late Sun night/early Monday as the precip comes to an end.
A soggy weekend overall, with temps struggling into the 50s for
Sunday.

Next week will see a return of some cold temps as another trof digs
into the center of the country.  A chance at a clipper system
starting to show up in the model runs for Wednesday, potentially
impacting a busy travel day, and have upped to a chance pop to start
the trend for that system a little earlier than the SuperBlend.


&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY from 9 PM this evening to 4 AM CST
Saturday FOR ILZ027>031-037-038-045.

FREEZING RAIN ADVISORY from 6 PM this evening to 1 AM CST
Saturday FOR ILZ036-040>044-047>051-053.

&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon








000
FXUS63 KILX 210951
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
351 AM CST Fri Nov 21 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST FRI NOV 21 2014

High pressure ridge over the region this morning with light and
variable winds across Central Illinois.  Another cold day expected
with highs in the low to upper 30s, but some moderation in the
airmass is expected going into the evening  hours. Southeasterly
winds increasing through the afternoon as the ridge axis slips
eastward.  Main issue for the forecast remains the onset of rain
this evening as the temps drop below freezing.  Models are still
changing a bit with the timing of the cold air and the approach of
the precip. Moisture advecting into the region on the back  side of
the ridge building some weak showers north as temperatures drop
after sunset. The window for freezing rain may be short-lived,
particularly along a line from Springfield to Jacksonville. Rain
spreading north into the region before the bulk of the warm air
moves into place and sfc temps will still be at or below freezing at
onset. Also, the ground is still frozen and am concerned that the
warm air will be a little slower to erode the cold dense air at the
sfc. Best chances for the freezing rain will be narrow and variable
windows from  6pm to midnight, shifting northward as the evening
progresses.  The threat will come to an end as the warm air works
its way into Central Illinois.  Some adjustment likely to the
advisory after the morning run of models comes in.  Variation with
every run has resulted in low confidence about the duration of the
freezing rain threat, so there is a bit of a cushion in the timing
of the ice accumulation.  Accumulations are expected to be low, and
in some areas, may see little more than freezing drizzle,
particularly east of the Interstate 55 corridor north of Lincoln,
closer to the drier air under the sfc ridge.  Either way, the first
icing event of the year, regardless of duration, will be issuing an
advisory.  Freezing rain advisory out for the evening hours, ending
before the morning traffic picks up.


&&

.LONG TERM...(Tonight through Thursday)
ISSUED AT 349 AM CST FRI NOV 21 2014

More southerly winds will begin to set up late Friday in advance of
a developing system to the SW. Same developing system will continue
to produce rain through the weekend.  A gap continues to show up in
the models between the developing warm frontal feature and the core
of the sfc low. But the timing is just different enough in the
GFS/NAM/ECMWF to maintain a rather high chance/likely pop through
the overnight Sat night. Best chances for the weekend is in the high
chance/likely category for precip, and has moved to categorical on
Sunday with the highest QPF.  Temps not high enough to significantly
warm the ground, so some frozen ground will increase some threat for
rising creeks and rivers with increased runoff. Beyond tonight,
Saturday through Sun night will be dominated by rain before possibly
seeing some snow on the back side of the system as cold air moves
back in late Sun night/early Monday as the precip comes to an end.
A soggy weekend overall, with temps struggling into the 50s for
Sunday.

Next week will see a return of some cold temps as another trof digs
into the center of the country.  A chance at a clipper system
starting to show up in the model runs for Wednesday, potentially
impacting a busy travel day, and have upped to a chance pop to start
the trend for that system a little earlier than the SuperBlend.


&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY from 9 PM this evening to 4 AM CST
Saturday FOR ILZ027>031-037-038-045.

FREEZING RAIN ADVISORY from 6 PM this evening to 1 AM CST
Saturday FOR ILZ036-040>044-047>051-053.

&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon







  [top]

000
FXUS63 KLOT 210911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
311 AM CST FRI NOV 21 2014

.SHORT TERM...
311 AM CST

THROUGH TONIGHT...

RIMARY FORECAST CHALLENGE IS WITH FREEZING RAIN EVENT TONIGHT.
SURFACE HIGH WILL MOVE EAST OF THE REGION TODAY ALLOWING FOR
SOUTHERLY WINDS TO DEVELOP TODAY AND BEGIN THE SLOW PROCESS OF
DISPLACING THE ARCTIC AIR THAT HAS BEEN ENTRENCHED OVER THE AREA.
COMPARING THE WRF-NAM MODEL TO VISIBLE SATELLITE SUGGESTS THERE IS
LESS SNOW COVER THAN INITIALIZED IN THE NAM AND HAVE GENERALLY
TRENDED TEMPS TODAY AND TONIGHT A BIT TOWARD THE WARMER GUIDANCE
WITH HIGHS MOSTLY IN THE LOWER 30S.

CLOUDS RAPIDLY INCREASE TONIGHT AND ONLY ALLOW FOR A MODEST DROP IN
TEMPS AT SUNSET...BUT STILL ANTICIPATE EVERYONE TO DROP INTO THE MID
TO UPPER 20S THIS EVENING. A STRONG LOW LEVEL JET IS PROGGED TO
DEVELOP TONIGHT IN ADVANCE OF A LEAD SHORTWAVE TROUGH JUST NOW
EMERGING OUT ONTO THE CENTRAL HIGH PLAINS. THE STRONG LOW LEVEL JET
WILL RESULT IN THE RAPID NORTHWARD TRANSPORT OF HIGHER THETA-E AIR
MASS ABOVE THE SURFACE WHILE SOME MODEST COOLING OF THE MID LEVELS
RESULTING IN STEEPENING LOW/MID LEVEL LAPSE RATES ABOVE THE LOW
LEVEL INVERSION. SREF PLUMES SHOW SOME WEAK MUCAPE VALUES SO WITH OR
WITHOUT LIGHTING EXPECT PRECIP TO BE CONVECTIVE IN NATURE TONIGHT
WITH SOMEWHAT VARIABLE AMOUNTS. SOME OF THE CONVECTIVE ALLOWING
MODELS CRANK OUT ALMOST A QUARTER INCH OF QPF AND WITH EXPECTED
CONVECTIVE NATURE OF QPF WOULD NOT BE SURPRISED TO SEE ISOLATED
AREAS SEE UP TO TWO TENTH OF AN INCH OF ICE ACCUMULATION WITH THE
HEAVIEST SHOWERS. SUNSHINE THURSDAY ALLOWED PAVEMENT SURFACE TEMPS
TO WARM INTO THE MID-UPPER 30S AND SUNSHINE TODAY SHOULD ALLOW FOR
SIMILAR READINGS BUT AFTER SUNSET THEY SHOULD FALL BELOW FREEZING
AGAIN FAIRLY QUICKLY...SO ANTICIPATE TRAVEL PROBLEMS WITH ANY
PRECIP. THE AMOUNT OF FREEZING RAIN NEEDED TO CAUSE MAJOR TRAVEL
PROBLEMS IS MINIMAL AND HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY
FOR TONIGHT TO COVER THIS THREAT.

IZZI

&&

.LONG TERM...
311 AM CST

IN THE WAKE OF THE LEAD SHORTWAVE LOOK FOR A CONTINUED CHANCE OF
SOME PERIODIC LIGHT RAIN OR DRIZZLE SATURDAY INTO SATURDAY NIGHT
BEFORE THE MAIN SOUTHERN STREAM SHORTWAVE LIFTS NORTHEASTWARD INTO
THE REGION LATER THIS WEEKEND PRODUCING MORE WIDESPREAD AND HEAVIER
RAIN VERY LATE SAT NIGHT THROUGH EARLY SUNDAY EVENING. HIGH PWATS
CERTAINLY FAVOR SOME RESPECTABLE RAINFALL TOTALS...POTENTIALLY IN
EXCESS OF AN INCH. THE LONG DURATION AND MOSTLY LIGHT-MODERATE
NATURE OF THE RAIN SHOULDN`T RESULT IN ANY BIG FLOODING PROBLEMS
BEYOND PERHAPS SOME NUISANCE STANDING WATER IN THE TYPICAL LOW
SPOTS.

SYSTEM IS FORECAST TO PHASE WITH AMPLIFYING NORTHERN STREAM TROUGH
OVER THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY RESULTING IN SFC
LOW DEEPENING TO POTENTIALLY SUB-980MB. DESPITE THE VERY DEEP NATURE
OF THE SFC LOW THE LATEST GUIDANCE IS NOT AS STRONG WITH THE HIGH IN
ITS WAKE SO WHILE BREEZY AND COLDER WITH SLOWLY FALLING TEMPS MONDAY
LATEST MODELS SUGGEST WINDS WON`T GET TOO OUT OF HAND. SOME SPORADIC
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE MONDAY AFTERNOON THROUGH
TUESDAY IN THE COLD MOIST CYCLONIC FLOW AROUND THE UPPER TROUGH.
WHILE MUCH MORE TEMPERED THAN THE RECENT RECORD COLD...STILL LOOKING
AT A HEALTHY SHOT OF ARCTIC AIR WITH 850MB TEMPS AROUND 2 SIGMA
BELOW AVG. LOCAL 850MB/925MB CLIMO SUPPORTS HIGHS IN THE 20S AGAIN
BY TUESDAY.

ANOTHER NORTHWEST FLOW SHORTWAVE IS PROGGED TO DIVE DOWN THE
BACKSIDE OF THE MEAN EASTERN NOAM TROUGH WEDNESDAY WITH CLIPPER
SYSTEM FORECAST TO DIVE SOUTHEAST TOWARD THE REGION. MEDIUM RANGE
MODELS HAVE SHOWN SOME RUN TO RUN CONSISTENCY IN DROPPING SOME
SYSTEM INTO THE AREA WEDNESDAY WITH A CHANCE OF SOME LIGHT
ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST. A LOT COULD CHANGE
BETWEEN NOW AND THEN BUT DID COORDINATE A MODEST INCREASE IN POPS
WITH NEIGHBORING OFFICES FOR WEDNESDAY GIVEN THE POTENTIAL HIGH
IMPACT OF ANY SNOW ON A BUSY TRAVEL DAY. FOR GOOD MEASURE MEDIUM
RANGE MODELS FOLLOW THAT CLIPPER UP WITH MORE ARCTIC AIR OF COURSE
IN TIME FOR THANKSGIVING.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 210911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
311 AM CST FRI NOV 21 2014

.SHORT TERM...
311 AM CST

THROUGH TONIGHT...

RIMARY FORECAST CHALLENGE IS WITH FREEZING RAIN EVENT TONIGHT.
SURFACE HIGH WILL MOVE EAST OF THE REGION TODAY ALLOWING FOR
SOUTHERLY WINDS TO DEVELOP TODAY AND BEGIN THE SLOW PROCESS OF
DISPLACING THE ARCTIC AIR THAT HAS BEEN ENTRENCHED OVER THE AREA.
COMPARING THE WRF-NAM MODEL TO VISIBLE SATELLITE SUGGESTS THERE IS
LESS SNOW COVER THAN INITIALIZED IN THE NAM AND HAVE GENERALLY
TRENDED TEMPS TODAY AND TONIGHT A BIT TOWARD THE WARMER GUIDANCE
WITH HIGHS MOSTLY IN THE LOWER 30S.

CLOUDS RAPIDLY INCREASE TONIGHT AND ONLY ALLOW FOR A MODEST DROP IN
TEMPS AT SUNSET...BUT STILL ANTICIPATE EVERYONE TO DROP INTO THE MID
TO UPPER 20S THIS EVENING. A STRONG LOW LEVEL JET IS PROGGED TO
DEVELOP TONIGHT IN ADVANCE OF A LEAD SHORTWAVE TROUGH JUST NOW
EMERGING OUT ONTO THE CENTRAL HIGH PLAINS. THE STRONG LOW LEVEL JET
WILL RESULT IN THE RAPID NORTHWARD TRANSPORT OF HIGHER THETA-E AIR
MASS ABOVE THE SURFACE WHILE SOME MODEST COOLING OF THE MID LEVELS
RESULTING IN STEEPENING LOW/MID LEVEL LAPSE RATES ABOVE THE LOW
LEVEL INVERSION. SREF PLUMES SHOW SOME WEAK MUCAPE VALUES SO WITH OR
WITHOUT LIGHTING EXPECT PRECIP TO BE CONVECTIVE IN NATURE TONIGHT
WITH SOMEWHAT VARIABLE AMOUNTS. SOME OF THE CONVECTIVE ALLOWING
MODELS CRANK OUT ALMOST A QUARTER INCH OF QPF AND WITH EXPECTED
CONVECTIVE NATURE OF QPF WOULD NOT BE SURPRISED TO SEE ISOLATED
AREAS SEE UP TO TWO TENTH OF AN INCH OF ICE ACCUMULATION WITH THE
HEAVIEST SHOWERS. SUNSHINE THURSDAY ALLOWED PAVEMENT SURFACE TEMPS
TO WARM INTO THE MID-UPPER 30S AND SUNSHINE TODAY SHOULD ALLOW FOR
SIMILAR READINGS BUT AFTER SUNSET THEY SHOULD FALL BELOW FREEZING
AGAIN FAIRLY QUICKLY...SO ANTICIPATE TRAVEL PROBLEMS WITH ANY
PRECIP. THE AMOUNT OF FREEZING RAIN NEEDED TO CAUSE MAJOR TRAVEL
PROBLEMS IS MINIMAL AND HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY
FOR TONIGHT TO COVER THIS THREAT.

IZZI

&&

.LONG TERM...
311 AM CST

IN THE WAKE OF THE LEAD SHORTWAVE LOOK FOR A CONTINUED CHANCE OF
SOME PERIODIC LIGHT RAIN OR DRIZZLE SATURDAY INTO SATURDAY NIGHT
BEFORE THE MAIN SOUTHERN STREAM SHORTWAVE LIFTS NORTHEASTWARD INTO
THE REGION LATER THIS WEEKEND PRODUCING MORE WIDESPREAD AND HEAVIER
RAIN VERY LATE SAT NIGHT THROUGH EARLY SUNDAY EVENING. HIGH PWATS
CERTAINLY FAVOR SOME RESPECTABLE RAINFALL TOTALS...POTENTIALLY IN
EXCESS OF AN INCH. THE LONG DURATION AND MOSTLY LIGHT-MODERATE
NATURE OF THE RAIN SHOULDN`T RESULT IN ANY BIG FLOODING PROBLEMS
BEYOND PERHAPS SOME NUISANCE STANDING WATER IN THE TYPICAL LOW
SPOTS.

SYSTEM IS FORECAST TO PHASE WITH AMPLIFYING NORTHERN STREAM TROUGH
OVER THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY RESULTING IN SFC
LOW DEEPENING TO POTENTIALLY SUB-980MB. DESPITE THE VERY DEEP NATURE
OF THE SFC LOW THE LATEST GUIDANCE IS NOT AS STRONG WITH THE HIGH IN
ITS WAKE SO WHILE BREEZY AND COLDER WITH SLOWLY FALLING TEMPS MONDAY
LATEST MODELS SUGGEST WINDS WON`T GET TOO OUT OF HAND. SOME SPORADIC
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE MONDAY AFTERNOON THROUGH
TUESDAY IN THE COLD MOIST CYCLONIC FLOW AROUND THE UPPER TROUGH.
WHILE MUCH MORE TEMPERED THAN THE RECENT RECORD COLD...STILL LOOKING
AT A HEALTHY SHOT OF ARCTIC AIR WITH 850MB TEMPS AROUND 2 SIGMA
BELOW AVG. LOCAL 850MB/925MB CLIMO SUPPORTS HIGHS IN THE 20S AGAIN
BY TUESDAY.

ANOTHER NORTHWEST FLOW SHORTWAVE IS PROGGED TO DIVE DOWN THE
BACKSIDE OF THE MEAN EASTERN NOAM TROUGH WEDNESDAY WITH CLIPPER
SYSTEM FORECAST TO DIVE SOUTHEAST TOWARD THE REGION. MEDIUM RANGE
MODELS HAVE SHOWN SOME RUN TO RUN CONSISTENCY IN DROPPING SOME
SYSTEM INTO THE AREA WEDNESDAY WITH A CHANCE OF SOME LIGHT
ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST. A LOT COULD CHANGE
BETWEEN NOW AND THEN BUT DID COORDINATE A MODEST INCREASE IN POPS
WITH NEIGHBORING OFFICES FOR WEDNESDAY GIVEN THE POTENTIAL HIGH
IMPACT OF ANY SNOW ON A BUSY TRAVEL DAY. FOR GOOD MEASURE MEDIUM
RANGE MODELS FOLLOW THAT CLIPPER UP WITH MORE ARCTIC AIR OF COURSE
IN TIME FOR THANKSGIVING.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 210911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
311 AM CST FRI NOV 21 2014

.SHORT TERM...
311 AM CST

THROUGH TONIGHT...

RIMARY FORECAST CHALLENGE IS WITH FREEZING RAIN EVENT TONIGHT.
SURFACE HIGH WILL MOVE EAST OF THE REGION TODAY ALLOWING FOR
SOUTHERLY WINDS TO DEVELOP TODAY AND BEGIN THE SLOW PROCESS OF
DISPLACING THE ARCTIC AIR THAT HAS BEEN ENTRENCHED OVER THE AREA.
COMPARING THE WRF-NAM MODEL TO VISIBLE SATELLITE SUGGESTS THERE IS
LESS SNOW COVER THAN INITIALIZED IN THE NAM AND HAVE GENERALLY
TRENDED TEMPS TODAY AND TONIGHT A BIT TOWARD THE WARMER GUIDANCE
WITH HIGHS MOSTLY IN THE LOWER 30S.

CLOUDS RAPIDLY INCREASE TONIGHT AND ONLY ALLOW FOR A MODEST DROP IN
TEMPS AT SUNSET...BUT STILL ANTICIPATE EVERYONE TO DROP INTO THE MID
TO UPPER 20S THIS EVENING. A STRONG LOW LEVEL JET IS PROGGED TO
DEVELOP TONIGHT IN ADVANCE OF A LEAD SHORTWAVE TROUGH JUST NOW
EMERGING OUT ONTO THE CENTRAL HIGH PLAINS. THE STRONG LOW LEVEL JET
WILL RESULT IN THE RAPID NORTHWARD TRANSPORT OF HIGHER THETA-E AIR
MASS ABOVE THE SURFACE WHILE SOME MODEST COOLING OF THE MID LEVELS
RESULTING IN STEEPENING LOW/MID LEVEL LAPSE RATES ABOVE THE LOW
LEVEL INVERSION. SREF PLUMES SHOW SOME WEAK MUCAPE VALUES SO WITH OR
WITHOUT LIGHTING EXPECT PRECIP TO BE CONVECTIVE IN NATURE TONIGHT
WITH SOMEWHAT VARIABLE AMOUNTS. SOME OF THE CONVECTIVE ALLOWING
MODELS CRANK OUT ALMOST A QUARTER INCH OF QPF AND WITH EXPECTED
CONVECTIVE NATURE OF QPF WOULD NOT BE SURPRISED TO SEE ISOLATED
AREAS SEE UP TO TWO TENTH OF AN INCH OF ICE ACCUMULATION WITH THE
HEAVIEST SHOWERS. SUNSHINE THURSDAY ALLOWED PAVEMENT SURFACE TEMPS
TO WARM INTO THE MID-UPPER 30S AND SUNSHINE TODAY SHOULD ALLOW FOR
SIMILAR READINGS BUT AFTER SUNSET THEY SHOULD FALL BELOW FREEZING
AGAIN FAIRLY QUICKLY...SO ANTICIPATE TRAVEL PROBLEMS WITH ANY
PRECIP. THE AMOUNT OF FREEZING RAIN NEEDED TO CAUSE MAJOR TRAVEL
PROBLEMS IS MINIMAL AND HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY
FOR TONIGHT TO COVER THIS THREAT.

IZZI

&&

.LONG TERM...
311 AM CST

IN THE WAKE OF THE LEAD SHORTWAVE LOOK FOR A CONTINUED CHANCE OF
SOME PERIODIC LIGHT RAIN OR DRIZZLE SATURDAY INTO SATURDAY NIGHT
BEFORE THE MAIN SOUTHERN STREAM SHORTWAVE LIFTS NORTHEASTWARD INTO
THE REGION LATER THIS WEEKEND PRODUCING MORE WIDESPREAD AND HEAVIER
RAIN VERY LATE SAT NIGHT THROUGH EARLY SUNDAY EVENING. HIGH PWATS
CERTAINLY FAVOR SOME RESPECTABLE RAINFALL TOTALS...POTENTIALLY IN
EXCESS OF AN INCH. THE LONG DURATION AND MOSTLY LIGHT-MODERATE
NATURE OF THE RAIN SHOULDN`T RESULT IN ANY BIG FLOODING PROBLEMS
BEYOND PERHAPS SOME NUISANCE STANDING WATER IN THE TYPICAL LOW
SPOTS.

SYSTEM IS FORECAST TO PHASE WITH AMPLIFYING NORTHERN STREAM TROUGH
OVER THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY RESULTING IN SFC
LOW DEEPENING TO POTENTIALLY SUB-980MB. DESPITE THE VERY DEEP NATURE
OF THE SFC LOW THE LATEST GUIDANCE IS NOT AS STRONG WITH THE HIGH IN
ITS WAKE SO WHILE BREEZY AND COLDER WITH SLOWLY FALLING TEMPS MONDAY
LATEST MODELS SUGGEST WINDS WON`T GET TOO OUT OF HAND. SOME SPORADIC
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE MONDAY AFTERNOON THROUGH
TUESDAY IN THE COLD MOIST CYCLONIC FLOW AROUND THE UPPER TROUGH.
WHILE MUCH MORE TEMPERED THAN THE RECENT RECORD COLD...STILL LOOKING
AT A HEALTHY SHOT OF ARCTIC AIR WITH 850MB TEMPS AROUND 2 SIGMA
BELOW AVG. LOCAL 850MB/925MB CLIMO SUPPORTS HIGHS IN THE 20S AGAIN
BY TUESDAY.

ANOTHER NORTHWEST FLOW SHORTWAVE IS PROGGED TO DIVE DOWN THE
BACKSIDE OF THE MEAN EASTERN NOAM TROUGH WEDNESDAY WITH CLIPPER
SYSTEM FORECAST TO DIVE SOUTHEAST TOWARD THE REGION. MEDIUM RANGE
MODELS HAVE SHOWN SOME RUN TO RUN CONSISTENCY IN DROPPING SOME
SYSTEM INTO THE AREA WEDNESDAY WITH A CHANCE OF SOME LIGHT
ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST. A LOT COULD CHANGE
BETWEEN NOW AND THEN BUT DID COORDINATE A MODEST INCREASE IN POPS
WITH NEIGHBORING OFFICES FOR WEDNESDAY GIVEN THE POTENTIAL HIGH
IMPACT OF ANY SNOW ON A BUSY TRAVEL DAY. FOR GOOD MEASURE MEDIUM
RANGE MODELS FOLLOW THAT CLIPPER UP WITH MORE ARCTIC AIR OF COURSE
IN TIME FOR THANKSGIVING.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 210911
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
311 AM CST FRI NOV 21 2014

.SHORT TERM...
311 AM CST

THROUGH TONIGHT...

RIMARY FORECAST CHALLENGE IS WITH FREEZING RAIN EVENT TONIGHT.
SURFACE HIGH WILL MOVE EAST OF THE REGION TODAY ALLOWING FOR
SOUTHERLY WINDS TO DEVELOP TODAY AND BEGIN THE SLOW PROCESS OF
DISPLACING THE ARCTIC AIR THAT HAS BEEN ENTRENCHED OVER THE AREA.
COMPARING THE WRF-NAM MODEL TO VISIBLE SATELLITE SUGGESTS THERE IS
LESS SNOW COVER THAN INITIALIZED IN THE NAM AND HAVE GENERALLY
TRENDED TEMPS TODAY AND TONIGHT A BIT TOWARD THE WARMER GUIDANCE
WITH HIGHS MOSTLY IN THE LOWER 30S.

CLOUDS RAPIDLY INCREASE TONIGHT AND ONLY ALLOW FOR A MODEST DROP IN
TEMPS AT SUNSET...BUT STILL ANTICIPATE EVERYONE TO DROP INTO THE MID
TO UPPER 20S THIS EVENING. A STRONG LOW LEVEL JET IS PROGGED TO
DEVELOP TONIGHT IN ADVANCE OF A LEAD SHORTWAVE TROUGH JUST NOW
EMERGING OUT ONTO THE CENTRAL HIGH PLAINS. THE STRONG LOW LEVEL JET
WILL RESULT IN THE RAPID NORTHWARD TRANSPORT OF HIGHER THETA-E AIR
MASS ABOVE THE SURFACE WHILE SOME MODEST COOLING OF THE MID LEVELS
RESULTING IN STEEPENING LOW/MID LEVEL LAPSE RATES ABOVE THE LOW
LEVEL INVERSION. SREF PLUMES SHOW SOME WEAK MUCAPE VALUES SO WITH OR
WITHOUT LIGHTING EXPECT PRECIP TO BE CONVECTIVE IN NATURE TONIGHT
WITH SOMEWHAT VARIABLE AMOUNTS. SOME OF THE CONVECTIVE ALLOWING
MODELS CRANK OUT ALMOST A QUARTER INCH OF QPF AND WITH EXPECTED
CONVECTIVE NATURE OF QPF WOULD NOT BE SURPRISED TO SEE ISOLATED
AREAS SEE UP TO TWO TENTH OF AN INCH OF ICE ACCUMULATION WITH THE
HEAVIEST SHOWERS. SUNSHINE THURSDAY ALLOWED PAVEMENT SURFACE TEMPS
TO WARM INTO THE MID-UPPER 30S AND SUNSHINE TODAY SHOULD ALLOW FOR
SIMILAR READINGS BUT AFTER SUNSET THEY SHOULD FALL BELOW FREEZING
AGAIN FAIRLY QUICKLY...SO ANTICIPATE TRAVEL PROBLEMS WITH ANY
PRECIP. THE AMOUNT OF FREEZING RAIN NEEDED TO CAUSE MAJOR TRAVEL
PROBLEMS IS MINIMAL AND HAVE OPTED TO HOIST A FREEZING RAIN ADVISORY
FOR TONIGHT TO COVER THIS THREAT.

IZZI

&&

.LONG TERM...
311 AM CST

IN THE WAKE OF THE LEAD SHORTWAVE LOOK FOR A CONTINUED CHANCE OF
SOME PERIODIC LIGHT RAIN OR DRIZZLE SATURDAY INTO SATURDAY NIGHT
BEFORE THE MAIN SOUTHERN STREAM SHORTWAVE LIFTS NORTHEASTWARD INTO
THE REGION LATER THIS WEEKEND PRODUCING MORE WIDESPREAD AND HEAVIER
RAIN VERY LATE SAT NIGHT THROUGH EARLY SUNDAY EVENING. HIGH PWATS
CERTAINLY FAVOR SOME RESPECTABLE RAINFALL TOTALS...POTENTIALLY IN
EXCESS OF AN INCH. THE LONG DURATION AND MOSTLY LIGHT-MODERATE
NATURE OF THE RAIN SHOULDN`T RESULT IN ANY BIG FLOODING PROBLEMS
BEYOND PERHAPS SOME NUISANCE STANDING WATER IN THE TYPICAL LOW
SPOTS.

SYSTEM IS FORECAST TO PHASE WITH AMPLIFYING NORTHERN STREAM TROUGH
OVER THE UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY RESULTING IN SFC
LOW DEEPENING TO POTENTIALLY SUB-980MB. DESPITE THE VERY DEEP NATURE
OF THE SFC LOW THE LATEST GUIDANCE IS NOT AS STRONG WITH THE HIGH IN
ITS WAKE SO WHILE BREEZY AND COLDER WITH SLOWLY FALLING TEMPS MONDAY
LATEST MODELS SUGGEST WINDS WON`T GET TOO OUT OF HAND. SOME SPORADIC
LIGHT SNOW SHOWERS OR FLURRIES ARE POSSIBLE MONDAY AFTERNOON THROUGH
TUESDAY IN THE COLD MOIST CYCLONIC FLOW AROUND THE UPPER TROUGH.
WHILE MUCH MORE TEMPERED THAN THE RECENT RECORD COLD...STILL LOOKING
AT A HEALTHY SHOT OF ARCTIC AIR WITH 850MB TEMPS AROUND 2 SIGMA
BELOW AVG. LOCAL 850MB/925MB CLIMO SUPPORTS HIGHS IN THE 20S AGAIN
BY TUESDAY.

ANOTHER NORTHWEST FLOW SHORTWAVE IS PROGGED TO DIVE DOWN THE
BACKSIDE OF THE MEAN EASTERN NOAM TROUGH WEDNESDAY WITH CLIPPER
SYSTEM FORECAST TO DIVE SOUTHEAST TOWARD THE REGION. MEDIUM RANGE
MODELS HAVE SHOWN SOME RUN TO RUN CONSISTENCY IN DROPPING SOME
SYSTEM INTO THE AREA WEDNESDAY WITH A CHANCE OF SOME LIGHT
ACCUMULATING SNOW SOMEWHERE IN THE MIDWEST. A LOT COULD CHANGE
BETWEEN NOW AND THEN BUT DID COORDINATE A MODEST INCREASE IN POPS
WITH NEIGHBORING OFFICES FOR WEDNESDAY GIVEN THE POTENTIAL HIGH
IMPACT OF ANY SNOW ON A BUSY TRAVEL DAY. FOR GOOD MEASURE MEDIUM
RANGE MODELS FOLLOW THAT CLIPPER UP WITH MORE ARCTIC AIR OF COURSE
IN TIME FOR THANKSGIVING.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 210906
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
306 AM CST FRI NOV 21 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 210906
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
306 AM CST FRI NOV 21 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* INCREASING SOUTHERLY WINDS...POSSIBLE CROSSWIND ISSUES THIS
  AFTERNOON.

* FREEZING RAIN LIKELY OVERNIGHT INTO EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM TO HIGH CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY
  NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KLOT 210902
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
302 AM CST FRI NOV 21 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* INCREASING SOUTHERLY WINDS COULD CAUSE CROSSWIND ISSUES FRIDAY
  AFTERNOON.

* FREEZING RAIN IS POSSIBLE LATE FRIDAY NIGHT AND EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
254 AM CST

IN THE TIGHT GRADIENT BETWEEN A DEEPENING LOW TO OUR NORTH AND
HIGH PRESSURE TO OUR SOUTHEAST...WINDS START WEST TODAY THEN
BACK SOUTH BY TONIGHT WHILE INCREASING TO STRONG GALES. THE NORTH
END OF THE LAKE LIKELY WILL SEE STRONGER AND EARLIER GALES THAN
THE SOUTH END...THUS THE TWO DIFFERENT START TIMES ON THE
WARNINGS. FOR SIMPLICITY THEY BOTH END AT THE SAME TIME SATURDAY
MORNING BUT LIKELY THE SOUTH WILL SEE GALES DIMINISH SOONER.

THE NEXT LOW PRESSURE SYSTEMS LIFT THROUGH ON MONDAY AND LIKELY
BRING ANOTHER PERIOD OF WEST GALES THAT AFTERNOON AND EVENING.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZING RAIN ADVISORY...ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-
     ILZ039...10 PM FRIDAY TO 6 AM SATURDAY.

     FREEZING RAIN ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
     ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022...11 PM
     FRIDAY TO 9 AM SATURDAY.

IN...FREEZING RAIN ADVISORY...INZ001-INZ002...11 PM FRIDAY TO 9 AM
     SATURDAY.

     FREEZING RAIN ADVISORY...INZ010-INZ011-INZ019...10 PM FRIDAY TO
     6 AM SATURDAY.

LM...GALE WARNING...LMZ080-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ872-
     LMZ874-LMZ876-LMZ878...9 PM FRIDAY TO 9 AM SATURDAY.

     GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...3 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

&&

$$

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000
FXUS63 KLOT 210551
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1151 PM CST THU NOV 20 2014

.UPDATE...
858 PM CST

HIGH PRESSURE CONTINUES TO STEADILY MOVE SOUTHEAST ACROSS IOWA
THIS EVENING AND WILL MOVE RIGHT OVER THE LOCAL AREA OVERNIGHT.
WINDS HAVE REMAINED STEADY FOR MOST OF THE AREA SO FAR THIS
EVENING BUT THEY WILL BE DROPPING OFF AS THE HIGH COMES ACROSS.
THIS WILL COMBINE WITH THE CLEAR SKIES TO ALLOW TEMPERATURES TO
QUICKLY FALL OVERNIGHT. CURRENT DEWPOINTS IN THE 3 TO 10 DEGREE
RANGE SUPPORT LOWS IN THE LOWER SINGLE DIGITS TO AROUND 10 DEGREES
WITH THE COLDEST READINGS NORTH. HAVE LOWERED LOWS IN THE NORTH A
FEW DEGREES AND WOULD NOT BE SURPRISED IF A FEW OF THE
TRADITIONALLY COLDER SPOTS FROM ROCHELLE TO AURORA SEE LOWS FALL
TO ZERO.

MDB

&&

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* INCREASING SOUTHERLY WINDS COULD CAUSE CROSSWIND ISSUES FRIDAY
  AFTERNOON.

* FREEZING RAIN IS POSSIBLE LATE FRIDAY NIGHT AND EARLY SATURDAY.

LENNING

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE MOVING OVERHEAD WILL SUPPORT LIGHT WINDS OVERNIGHT.
WINDS TURN SOUTH DURING THE MORNING AND INCREASE IN SPEED DURING
THE AFTERNOON. THESE BREEZY SOUTH TO SSW WINDS PERSIST THROUGH
SATURDAY.

RAIN CHANCES INCREASE FRIDAY NIGHT AND TEMPERATURES WILL SLOWLY BE
ON THE RISE DURING FRIDAY NIGHT AS WELL. UNFORTUNATELY THE RAIN IS
LIKELY TO ARRIVE BEFORE TEMPERATURES CLIMB ABOVE FREEZING. THE PEAK
PERIOD OF CONCERN APPEARS TO BE IN THE PREDAWN HOURS MOSTLY BEFORE
TRAFFIC PICKS UP...BUT FREEZING RAIN COULD LINGER INTO THE FIRST
COUPLE HOURS OF THE MORNING RUSH.

LENNING

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN WIND...CEILING...AND VSBY TRENDS.

* MEDIUM CONFIDENCE IN FZRA TIMING AND CHANCES FRIDAY NIGHT.

LENNING

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTH CENTRAL QUEBEC WILL CONTINUE TO SLIDE
EAST. AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE
NORTHERN PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL
SLOWLY MOVE EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL
BRING MUCH LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY
MORNING...HOWEVER HIGH PRESSURE IS EXPECTED TO CONTINUE TO SLIDE
EAST TOWARDS THE MIDDLE ATLANTIC REGION BY LATE FRIDAY NIGHT. AS
HIGH PRESSURE DEPARTS LAKE MICHIGAN...WINDS WILL TURN SOUTHWEST TO
SOUTH FRIDAY NIGHT. AN AREA OF LOW PRESSURE WILL SLIDE EAST ACROSS
MANITOBA TOWARDS JAMES BAY...WITH A TIGHTENING GRADIENT EXPECTED
TO DEVELOP BY LATE FRIDAY NIGHT ACROSS CENTRAL/NORTHERN LAKE
MICHIGAN. HAVE HELD IN PLACE THE GALE WATCH...HOWEVER THIS MAY
NEED TO BE UPGRADED TO A GALE WARNING. THE MAIN CONCERN IS THAT
WITH MUCH WARMER AIR POISED TO ARRIVE FRIDAY NGT...THAT THIS MAY
CREATE LESS MIXING TO THE SURFACE OF THE HIGHER WIND GUSTS.
GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO ALONG THE
MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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000
FXUS63 KILX 210551
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1151 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 210551
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1151 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 210551
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1151 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 210551
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1151 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 1151 PM CST THU NOV 20 2014

The surface ridge has pushed into IL, and will continue a slow
trek across IL through the morning. Winds will be either light
north or variable under the ridge axis. As the ridge advances east of
the terminal sites on Friday, winds will increase from the
southeast. Winds speeds should climb into the 10-12kt range by 21z
Friday. Mid clouds at 15k ft will advance into the region from the
SW as moisture begins to overrun the cold high pressure. Low level
saturation will hold off until Friday evening, as warming begins
at all levels. It appears SPI and DEC may remain above freezing
as the rain starts, but we left a tempo for the possibility of a
short period of FZRA at the onset of pcpn. Farther north,
PIA/BMI/CMI will have a better chance of a few hours of FZRA
before the mid-level warming gets so strong that the raindrops can
no longer freeze on contact. The timing of that warming remains in
question, and if the GFS verifies, the period of FZRA would be
very short-lived at any location. The NAM is much colder, and
indicates several hours of FZRA for our northern terminals from
mid evening to just after midnight. Light icing could cause very
slippery conditions as the freezing rain falls on cold and dry
ground at the onset of pcpn.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KLOT 210302
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
902 PM CST THU NOV 20 2014

.UPDATE...
858 PM CST

HIGH PRESSURE CONTINUES TO STEADILY MOVE SOUTHEAST ACROSS IOWA
THIS EVENING AND WILL MOVE RIGHT OVER THE LOCAL AREA OVERNIGHT.
WINDS HAVE REMAINED STEADY FOR MOST OF THE AREA SO FAR THIS
EVENING BUT THEY WILL BE DROPPING OFF AS THE HIGH COMES ACROSS.
THIS WILL COMBINE WITH THE CLEAR SKIES TO ALLOW TEMPERATURES TO
QUICKLY FALL OVERNIGHT. CURRENT DEWPOINTS IN THE 3 TO 10 DEGREE
RANGE SUPPORT LOWS IN THE LOWER SINGLE DIGITS TO AROUND 10 DEGREES
WITH THE COLDEST READINGS NORTH. HAVE LOWERED LOWS IN THE NORTH A
FEW DEGREES AND WOULD NOT BE SURPRISED IF A FEW OF THE
TRADITIONALLY COLDER SPOTS FROM ROCHELLE TO AURORA SEE LOWS FALL
TO ZERO.

MDB

&&

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTH CENTRAL QUEBEC WILL CONTINUE TO SLIDE
EAST. AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE
NORTHERN PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL
SLOWLY MOVE EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL
BRING MUCH LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY
MORNING...HOWEVER HIGH PRESSURE IS EXPECTED TO CONTINUE TO SLIDE
EAST TOWARDS THE MIDDLE ATLANTIC REGION BY LATE FRIDAY NIGHT. AS
HIGH PRESSURE DEPARTS LAKE MICHIGAN...WINDS WILL TURN SOUTHWEST TO
SOUTH FRIDAY NIGHT. AN AREA OF LOW PRESSURE WILL SLIDE EAST ACROSS
MANITOBA TOWARDS JAMES BAY...WITH A TIGHTENING GRADIENT EXPECTED
TO DEVELOP BY LATE FRIDAY NIGHT ACROSS CENTRAL/NORTHERN LAKE
MICHIGAN. HAVE HELD IN PLACE THE GALE WATCH...HOWEVER THIS MAY
NEED TO BE UPGRADED TO A GALE WARNING. THE MAIN CONCERN IS THAT
WITH MUCH WARMER AIR POISED TO ARRIVE FRIDAY NGT...THAT THIS MAY
CREATE LESS MIXING TO THE SURFACE OF THE HIGHER WIND GUSTS.
GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO ALONG THE
MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 210302
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
902 PM CST THU NOV 20 2014

.UPDATE...
858 PM CST

HIGH PRESSURE CONTINUES TO STEADILY MOVE SOUTHEAST ACROSS IOWA
THIS EVENING AND WILL MOVE RIGHT OVER THE LOCAL AREA OVERNIGHT.
WINDS HAVE REMAINED STEADY FOR MOST OF THE AREA SO FAR THIS
EVENING BUT THEY WILL BE DROPPING OFF AS THE HIGH COMES ACROSS.
THIS WILL COMBINE WITH THE CLEAR SKIES TO ALLOW TEMPERATURES TO
QUICKLY FALL OVERNIGHT. CURRENT DEWPOINTS IN THE 3 TO 10 DEGREE
RANGE SUPPORT LOWS IN THE LOWER SINGLE DIGITS TO AROUND 10 DEGREES
WITH THE COLDEST READINGS NORTH. HAVE LOWERED LOWS IN THE NORTH A
FEW DEGREES AND WOULD NOT BE SURPRISED IF A FEW OF THE
TRADITIONALLY COLDER SPOTS FROM ROCHELLE TO AURORA SEE LOWS FALL
TO ZERO.

MDB

&&

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN

//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTH CENTRAL QUEBEC WILL CONTINUE TO SLIDE
EAST. AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE
NORTHERN PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL
SLOWLY MOVE EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL
BRING MUCH LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY
MORNING...HOWEVER HIGH PRESSURE IS EXPECTED TO CONTINUE TO SLIDE
EAST TOWARDS THE MIDDLE ATLANTIC REGION BY LATE FRIDAY NIGHT. AS
HIGH PRESSURE DEPARTS LAKE MICHIGAN...WINDS WILL TURN SOUTHWEST TO
SOUTH FRIDAY NIGHT. AN AREA OF LOW PRESSURE WILL SLIDE EAST ACROSS
MANITOBA TOWARDS JAMES BAY...WITH A TIGHTENING GRADIENT EXPECTED
TO DEVELOP BY LATE FRIDAY NIGHT ACROSS CENTRAL/NORTHERN LAKE
MICHIGAN. HAVE HELD IN PLACE THE GALE WATCH...HOWEVER THIS MAY
NEED TO BE UPGRADED TO A GALE WARNING. THE MAIN CONCERN IS THAT
WITH MUCH WARMER AIR POISED TO ARRIVE FRIDAY NGT...THAT THIS MAY
CREATE LESS MIXING TO THE SURFACE OF THE HIGHER WIND GUSTS.
GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO ALONG THE
MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 210256
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
856 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 552 PM CST THU NOV 20 2014

The surface ridge extending from SE North Dakota across SW Illinois will
push east across IL over the next 24 hours. Winds tonight will
start out WNW at 7 to 10 kt but become light and variable by late
evening. As the ridge axis advances east of the terminal sites on
Friday, winds will increase from the southeast. Winds speeds
should climb into the 10-12kt range by 21z Friday. Mid clouds at
15k ft will advance into the region from the SW as moisture begins
to overrun the cold high pressure. Any precipitation is expected
to hold off until after the end of this TAF period.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 210256
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
856 PM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 856 PM CST THU NOV 20 2014

High pressure will provide another very cold night with ideal
radiational cooling conditions. As the surface ridge axis
progresses directly over IL, winds will become light and variable
under clear skies. That will allow temps to drop into the single
digits toward Galesburg and Altona, with low to mid teens all the
way south to I-70. Some light snow cover from Paris to Effingham
will help produce slightly colder low temps in those areas.

Still seeing the potential for a few hours of freezing rain at the
onset of precipitation Friday evening. The GFS remains much warmer
than the NAM with the low level thermodynamics. Even the NAM shows
the peak warm layer temp climbing to +8C by midnight as far north
as I-74. That would diminish the potential for any continued
freezing of the rain after it reaches the ground based on expected
surface temps hovering very close to freezing at that time.

The main concern remains that any freezing rain initially would
be falling on dry and cold pavement, which could quickly produce
very slippery conditions even with just a few hundredths of
freezing rain. The warming trend from south to north the rest of
the night should help any ice begin to melt after a few hours of
icy conditions.

Overall, the current forecast grids have a good handle on the
expected trends over the next 12-24 hours, and no formal update
will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 552 PM CST THU NOV 20 2014

The surface ridge extending from SE North Dakota across SW Illinois will
push east across IL over the next 24 hours. Winds tonight will
start out WNW at 7 to 10 kt but become light and variable by late
evening. As the ridge axis advances east of the terminal sites on
Friday, winds will increase from the southeast. Winds speeds
should climb into the 10-12kt range by 21z Friday. Mid clouds at
15k ft will advance into the region from the SW as moisture begins
to overrun the cold high pressure. Any precipitation is expected
to hold off until after the end of this TAF period.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon







000
FXUS63 KILX 202353
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
553 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 552 PM CST THU NOV 20 2014

The surface ridge extending from SE North Dakota across SW Illinois will
push east across IL over the next 24 hours. Winds tonight will
start out WNW at 7 to 10 kt but become light and variable by late
evening. As the ridge axis advances east of the terminal sites on
Friday, winds will increase from the southeast. Winds speeds
should climb into the 10-12kt range by 21z Friday. Mid clouds at
15k ft will advance into the region from the SW as moisture begins
to overrun the cold high pressure. Any precipitation is expected
to hold off until after the end of this TAF period.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 202353
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
553 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.

&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from Canada into northern IL and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 552 PM CST THU NOV 20 2014

The surface ridge extending from SE North Dakota across SW Illinois will
push east across IL over the next 24 hours. Winds tonight will
start out WNW at 7 to 10 kt but become light and variable by late
evening. As the ridge axis advances east of the terminal sites on
Friday, winds will increase from the southeast. Winds speeds
should climb into the 10-12kt range by 21z Friday. Mid clouds at
15k ft will advance into the region from the SW as moisture begins
to overrun the cold high pressure. Any precipitation is expected
to hold off until after the end of this TAF period.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Shimon







000
FXUS63 KLOT 202331
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
531 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202331
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
531 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202331
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
531 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202331
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
531 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* WINDS BECOMING SOUTHERLY BY LATE MORNING AND INCREASING TO
  AROUND 10KT THROUGH THE DAY.

KREIN

//DISCUSSION...UPDATED 00Z...

WITH HIGH PRESSURE SLIDING ACROSS THE REGION OVERNIGHT TONIGHT...
SKIES WILL BE CLEAR WITH WINDS DECREASING TO 5KT OR LESS. THROUGH
THE MORNING HOURS TOMORROW...THE CENTER OF THE HIGH WILL SETTLE
INTO THE OHIO VALLEY WHILE A TROUGH OF LOW PRESSURE DEVELOPS OVER
THE NORTHERN PLAINS. WINDS WILL BECOME SOUTHERLY AND WITH A MODEST
PRESSURE GRADIENT SETTING UP...WINDS SHOULD INCREASE TO ARND 10KT
BY LATE MORNING AND REMAIN AT THAT LEVEL THROUGH THE DAY. A MID
LEVEL IMPULSE LIFTING OUT OF THE SRN ROCKIES AND ACROSS THE
CENTRAL PLAINS TOMORROW WILL APPROACH THE REGION TOMORROW
EVENING. INCREASING CLOUD COVER IS EXPECTED THROUGH THE LATE
EVENING...WITH ANY ASSOCIATED PCPN LIKELY NOT MOVING INTO THE AREA
UNTIL AFTER MIDNIGHT TOMORROW NIGHT.

KREIN


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* CONFIDENCE IN ALL FORECAST ELEMENTS.

KREIN

//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...

SATURDAY...CHANCE OF RAIN OR FREEZING RAIN EARLY...THEN RAIN
LIKELY WITH DENSE FOG POSSIBLE OVERNIGHT. MVFR CONDITIONS LIKELY
THROUGH MUCH OF THE DAY...IFR CONDITIONS LIKELY OVERNIGHT. SOUTH-
SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. HEAVY AT TIMES. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR/WX NIL DURING THE DAY. SCHC -SN OVERNIGHT. MVFR
CIGS/VIS PSBL. WEST TO SOUTHWEST WINDS 10 KT OR LESS.

KREIN

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202204
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
404 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* GUSTY WEST WINDS THROUGH SUNSET MAX GUSTS 25-30 KT.

KREIN

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202204
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
404 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* GUSTY WEST WINDS THROUGH SUNSET MAX GUSTS 25-30 KT.

KREIN

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KREIN

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 202105
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
305 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 202105
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
305 PM CST THU NOV 20 2014

.SHORT TERM...

TONIGHT THROUGH SATURDAY...

305 PM...MAIN FORECAST CONCERN AND CHALLENGE REMAINS LIGHT
FREEZING RAIN POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY MORNING.

ANOTHER BLUSTERY DAY WITH WINDS GUSTING 30-35 MPH WITH TEMPS
REACHING THE UPPER 20S TO LOWER 30S ACROSS SOUTHERN AREAS. CLEAR
SKIES WILL CONTINUE INTO TONIGHT AS A RIDGE OF HIGH PRESSURE
BUILDS ACROSS THE REGION ALLOWING WINDS TO BECOME LIGHT AND
VARIABLE OVERNIGHT. ONE LAST NIGHT OF VERY COLD TEMPS...UNTIL
NEXT WEEK...WITH LOW TEMPS TANKING TO THE SINGLE DIGITS NORTH TO
PERHAPS LOWER TEENS ACROSS THE SOUTH.

AS THE RIDGE SHIFTS EAST FRIDAY...FLOW TURNS LIGHT SOUTHERLY AND
WITH QUITE A BIT OF SUN EXPECTED THRU EARLY AFTERNOON ALONG WITH
WARMING TEMPS ALOFT...SHOULD AT LEAST BE ABLE TO REACH SAME TEMPS
AS TODAY AND PERHAPS A FEW DEGREES WARMER.

WARMER AIR CONTINUES TO SPREAD NORTH FRIDAY NIGHT AS WEAK LIFT
BEGINS TO SQUEEZE OUT SOME LIGHT PRECIPITATION. AIR TEMPERATURES
WILL INITIALLY REMAIN BELOW FREEZING AS PRECIPITATION BEGINS TO
FALL. DRY LOW LEVELS MAY SUPPORT SOME LIGHT SLEET AT ONSET...BUT
APPEARS THE MAIN PRECIP TYPE WILL BE LIGHT FREEZING RAIN AS A VERY
DEEP WARM LAYER DEVELOPS OVERNIGHT. QPF AMOUNTS HAVE GENERALLY
RANGED FROM A FEW HUNDREDTHS ACROSS THE NORTHERN CWA TO PERHAPS AS
MUCH AS A TENTH OF AN INCH ACROSS THE SOUTHEAST CWA INTO NORTHWEST
INDIANA. SO A PERIOD OF LIGHT FREEZING RAIN APPEARS LIKELY.

MAIN QUESTION WILL THEN BE HOW LONG DOES IT PERSIST. GROUND
SURFACES HAVE BEEN SUB FREEZING FOR OVER A WEEK WITH HIGH TEMPS
MAYBE REACHING NEAR THE FREEZING MARK FRIDAY. THUS IT WILL TAKE
SOME AMOUNT OF TIME FOR AIR TEMPERATURES ABOVE FREEZING TO WARM
THESE COLDER SURFACES AND END FREEZING RAIN POTENTIAL. CONFIDENCE
ON THIS TIMING IS FAIRLY LOW. HOURLY TEMP TRENDS HAVE TEMPS INTO
THE MID 30S ACROSS THE SOUTHERN CWA AND TO AROUND FREEZING
NORTHERN AREAS BY 12Z SATURDAY. THESE TEMPS ARE IN LINE AND
PERHAPS A TAD COOLER THAN THE GFS/ECMWF. TEMPS CONTINUE TO
STEADILY RISE THROUGH THE MID/UPPER 30S SATURDAY MORNING...WITH
PRECIPITATION BECOMING ALL LIQUID. ANY AMOUNT OF LIGHT FREEZING
RAIN OR FREEZING DRIZZLE WILL BECOME HAZARDOUS ON UNTREATED
SURFACES AND PLAN TO ISSUE AN SPS THIS AFTERNOON TO HIGHLIGHT THE
THREAT.

TEMPERATURES CONTINUE TO WARM INTO THE 40S SATURDAY WITH A CHANCE
OF LIGHT RAIN OR PERHAPS SOME DRIZZLE. CMS

&&

.LONG TERM...

SATURDAY NIGHT THROUGH FRIDAY...

305 PM...MAIN FORECAST CONCERNS ARE HEAVY RAIN SUNDAY/SUNDAY
EVENING AND THEN ANOTHER PROLONGED PERIOD OF COLDER/BELOW NORMAL
TEMPS NEXT WEEK.

NOT MUCH CHANGE IN TEMPS IS EXPECTED SATURDAY NIGHT AS LOW LEVEL
MOISTURE STREAMS NORTH. TEMPS MAY HOLD STEADY IN THE LOWER TO MID
40S. EXTENT OF FOG IS STILL A BIT UNCERTAIN BUT POTENTIAL FOR FOG
CONTINUES HIGH ENOUGH TO MAINTAIN IN THE FORECAST WITH AT LEAST
THE CHANCE OF SOME DENSE FOG.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND MOVE NORTH ACROSS THE AREA SUNDAY AFTERNOON OR SUNDAY EVENING.
WHILE THE LOW IS STILL EXPECTED TO DEEPEN TO AS LOW AS 976MB OVER
THE NORTHERN LAKES MONDAY...IT MAY DEEPEN A BIT SLOWER AND ITS
OVERALL TRACK COULD BE A BIT SLOWER AND A TAD FURTHER EAST...FROM
EASTERN IL TO SOUTHERN MICHIGAN SUNDAY NIGHT. NET AFFECT OF THIS
WOULD BE TO BRING THE AXIS OF HEAVY RAIN RIGHT OVER THE CWA FROM
SUNDAY AFTERNOON INTO SUNDAY EVENING. PRECIPITABLE WATER VALUES
STILL PROGGED INTO THE 1.0 TO 1.2 INCH RANGE DURING THIS TIME
PERIOD. STORM TOTAL RAINFALL OF 1 TO 2 INCHES STILL LOOKS POSSIBLE
BUT NOT ENOUGH CERTAINTY TO TRY TO PIN DOWN A PARTICULAR AREA OF
THE CWA...IT MAY END UP BEING MUCH OF THE AREA.

TRACK OF THE LOW WILL ALSO LIKELY RESULT IN A RATHER SHARP TEMP
GRADIENT...PERHAPS ONLY LOW/MID 40S WESTERN AREAS AND LOW/MID 50S
FAR EASTERN AREAS. A COLD FRONT WILL MOVE ACROSS THE AREA SUNDAY
NIGHT BRINGING COLD AIR BACK TO THE AREA WITH FALLING TEMPS
THROUGH THE 30S MONDAY. LINGERING PRECIP WILL CHANGE FROM LIGHT
RAIN TO LIGHT SNOW WITH SNOW SHOWERS/FLURRIES POSSIBLE MONDAY INTO
MONDAY NIGHT. STILL LOOKS QUITE BREEZY EARLY NEXT WEEK WITH
SPECIFICS DEPENDING ON THE TRACK/STRENGTH/TIMING OF THE LOW.

CONFIDENCE REGARDING MID/LATE NEXT WEEK IS LOW. A WEAKER CLIPPER
LIKE SYSTEM IS SHOWN BY THE GFS ON WEDNESDAY AND THE ECMWF ON
THURSDAY WITH A STRONG COLD FRONT MOVING ACROSS THE AREA AND
ANOTHER PUNCH OF VERY COLD AIR. WHILE THEY ARE SIMILAR THE TIMING
DIFFERENCES ARE LARGE ENOUGH WITH LITTLE CONTINUITY FROM THE 00Z
ECMWF...TO NOT MAKE ANY BIG CHANGES AT THIS TIME. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KILX 202048
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.


&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from canada into northern il and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.


&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1120 AM CST THU NOV 20 2014

Subsidence behind weak trough has lead to SKC to SCT conditions
across the Central Illinois TAF sites has allowed momentum transfer
to produce wind gusts around 20 kts at times from west. The surface
ridge over Central U.S. will push east into the terminal sites
late this afternoon and overnight which should reduce winds and
gusts below 10 kts.

Southeast flow on backside of ridge is expected to develop Friday.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Barker







000
FXUS63 KILX 202048
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.


&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from canada into northern il and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.


&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1120 AM CST THU NOV 20 2014

Subsidence behind weak trough has lead to SKC to SCT conditions
across the Central Illinois TAF sites has allowed momentum transfer
to produce wind gusts around 20 kts at times from west. The surface
ridge over Central U.S. will push east into the terminal sites
late this afternoon and overnight which should reduce winds and
gusts below 10 kts.

Southeast flow on backside of ridge is expected to develop Friday.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Barker







000
FXUS63 KILX 202048
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.


&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from canada into northern il and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.


&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1120 AM CST THU NOV 20 2014

Subsidence behind weak trough has lead to SKC to SCT conditions
across the Central Illinois TAF sites has allowed momentum transfer
to produce wind gusts around 20 kts at times from west. The surface
ridge over Central U.S. will push east into the terminal sites
late this afternoon and overnight which should reduce winds and
gusts below 10 kts.

Southeast flow on backside of ridge is expected to develop Friday.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Barker







000
FXUS63 KILX 202048
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Thu Nov 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 248 PM CST THU NOV 20 2014

Surface ridge over lower Missouri Valley will push east into
Illinois overnight. Resultant drop in wind speeds will combine with
mostly clear sky to produce near ideal radiational cooling
conditions across central and southeast Illinois. Coolest readings
should be in GBG area and in the area from Paris to Effingham where
some snow cover is still observable in visible satellite. Have
generally used MAV guidance as NAM/WRF and resultant MET have been
on cold side last night and today.


&&

.LONG TERM...(Friday through Thursday)
ISSUED AT 248 PM CST THU NOV 20 2014

Upper air and moisture channel imagery this morning shows main
northerly jet from canada into northern il and then curving off to
the east. upper trof over eastern US is now moving east, as strong
closed low system seen moving coast to west coast. That system will
be the system that will trigger precipitation (pcpn) over midwest
into the weekend. Models similar in movement of that system, as
surface high pressure area over MO drifts off to the east.

As west coast system digs into the southwest US, surface high moving
into central east coast will aid in southern moisture advection from
the gulf into midwest n Friday. Cold air at surface will be overrun
by moisture from AR and MO, increasing on Friday and reaching region
Friday evening. Warm air overriding lingering cold dome will result
in some freezing rain on Friday evening, as the warm air advects
north into area. NAM and GFS soundings, and temperature Meteograms
show timing of the pcpn and the retreat/warming of the boundary
layer will be critical in freezing rain development. NAM seems to be
too cold, but each new run seems to warm NAM. Temperature timing in
Friday afternoon through evening and overnight was a blend of GFS
and a warming of the NAM. Freezing line is expected to retreat
northward over CWA in the evening and overnight, with brief freezing
in the south sections and longer periods in the north. Pcpn amounts
however, will be light, less than tenth of an inch. However some
slick areas will be possible on secondary roads.

For Saturday into Sunday, upper system will dig into TX and then
move north through midwest into Great Lakes by Sunday night. This
will bring periods of rain over region through the weekend, with the
heaviest rainfall on Sunday as the low center moves through. Colder
air moves in by Tuesday will some lingering pcpn.

Models then start to diverge for Wednesday and Thursday. Coordinated
will surrounding offices and consensus to drop pcpn chances for Wed
night into Thursday night until future model runs.


&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1120 AM CST THU NOV 20 2014

Subsidence behind weak trough has lead to SKC to SCT conditions
across the Central Illinois TAF sites has allowed momentum transfer
to produce wind gusts around 20 kts at times from west. The surface
ridge over Central U.S. will push east into the terminal sites
late this afternoon and overnight which should reduce winds and
gusts below 10 kts.

Southeast flow on backside of ridge is expected to develop Friday.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barker
LONG TERM...Goetsch
AVIATION...Barker







000
FXUS63 KLOT 202000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 202000
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
200 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
200 PM CST

LOW PRESSURE OVER SOUTHCENTRAL QUEBEC WILL CONTINUE TO SLIDE EAST.
AN ELONGATED RIDGE OF HIGH PRESSURE STRETCHES FROM THE NORTHERN
PLAINS SOUTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL SLOWLY MOVE
EAST TOWARDS LAKE MICHIGAN TONIGHT. HIGH PRESSURE WILL BRING MUCH
LIGHTER WINDS TO LAKE MICHIGAN BY FRIDAY MORNING...HOWEVER HIGH
PRESSURE IS EXPECTED TO CONTINUE TO SLIDE EAST TOWARDS THE MIDDLE
ATLANTIC REGION BY LATE FRIDAY NIGHT. AS HIGH PRESSURE DEPARTS LAKE
MICHIGAN...WINDS WILL TURN SOUTHWEST TO SOUTH FRIDAY NIGHT. AN AREA
OF LOW PRESSURE WILL SLIDE EAST ACROSS MANITOBA TOWARDS JAMES
BAY...WITH A TIGHTENING GRADIENT EXPECTED TO DEVELOP BY LATE FRIDAY
NIGHT ACROSS CENTRAL/NORTHERN LAKE MICHIGAN. HAVE HELD IN PLACE THE
GALE WATCH...HOWEVER THIS MAY NEED TO BE UPGRADED TO A GALE WARNING.
THE MAIN CONCERN IS THAT WITH MUCH WARMER AIR POISED TO ARRIVE
FRIDAY NGT...THAT THIS MAY CREATE LESS MIXING TO THE SURFACE OF THE
HIGHER WIND GUSTS. GUIDANCE SUGGESTS GALES MAY BE BETWEEN 34-37KT SO
ALONG THE MARGINAL LINES.

DURING THE DAY SATURDAY THE GRADIENT WILL DIMINISH ONCE AGAIN AND
TURN SOUTHEASTERLY...HOWEVER THIS WILL ONLY BE TEMPORARY AS A MORE
POTENT LOW PRESSURE SYSTEM IS POISED TO SLIDE SOUTHEAST FROM CENTRAL
CANADA SATURDAY NIGHT. A WEAKER LOW PRESSURE SYSTEM WILL DEVELOP
ACROSS THE SOUTHERN PLAINS EARLY SUNDAY...THEN QUICKLY LIFT NORTH
TOWARDS LAKE MICHIGAN. GUIDANCE DIFFERS ON THE EXACT STRENGTH AND
PATH OF THIS LOW...BUT MODELS INDICATE THE LOW WILL DEEPEN TO AROUND
975 MB/28.8 INCHES AT THE NORTH END OF THE LAKE MONDAY AFTERNOON.
EXPECTING SOUTHEAST WINDS TO INCREASE TO AT LEAST 30 KT THROUGH
SUNDAY EVENING AND THEN BECOME SOUTHWEST BEHIND THE LOW. GALES ARE
EXPECTED BY LATE SUNDAY NIGHT AND DEPENDING ON THE PATH AND STRENGTH
OF THE LOW...STORM FORCE WINDS MAY BE INCLUDED IN FUTURE FORECASTS.
GUIDANCE INDICATED A BRIEF PERIOD OF HIGH END GALES OVER THE
NORTHERN END OF THE LAKE MONDAY AFTERNOON.  THE LOW MOVES OVER
QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TUESDAY MORNING.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 201950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
150 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
150 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
150 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201950
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
150 PM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201735
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1135 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KLOT 201735
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1135 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KLOT 201735
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1135 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KLOT 201735
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1135 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS 25-30 KT.

KMD

//DISCUSSION...UPDATED 18Z...

SOME MVFR CUMULUS TRYING TO FORM THIS AFTERNOON BUT IT WILL HAVE A
HARD TIME GETTING MORE COVERAGE THAN SCATTERED. HIGH PRESSURE WILL
BE MOVING OVERHEAD TONIGHT...THUS SKIES CLEAR TONIGHT WITH WINDS
EASING FROM WEST TO EAST. WIND DIRECTION TRENDS TO SOUTH TOMORROW...PEAKING
AROUND 10 KT OR SO...POSSIBLY WITH A SLIGHT SE COMPONENT. EXPECT
AN INCREASE IN HIGH CLOUDS THROUGH THE DAY.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH CONFIDENCE IN ALL ELEMENTS

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 AM FRIDAY.

     SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 4 AM FRIDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KILX 201721
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1121 AM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 1031 AM CST THU NOV 20 2014

Forecast for today on track and only small tweaks to wind gusts
required this morning.

Weak trough pushing southeast over the area has produced a few
clouds south of I-72 particularly areas that still have snow on
the ground. behind the trough, skies are sunny to mostly sunny
allowing some momentum from higher winds several thousand feet off
surface. Have increased wind gusts for today in the grids. Surface
ridge over Mississippi Valley pushes east into Illinois by late
in the day and a drop off in winds and gusts are expected by mid-
afternoon. Diurnal effects should take care of any remnant gusting
by 00z.

Otherwise, current forecast in good shape.

&&

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1120 AM CST THU NOV 20 2014

Subsidence behind weak trough has lead to SKC to SCT conditions
across the Central Illinois TAF sites has allowed momentum transfer
to produce wind gusts around 20 kts at times from west. The surface
ridge over Central U.S. will push east into the terminal sites
late this afternoon and overnight which should reduce winds and
gusts below 10 kts.

Southeast flow on backside of ridge is expected to develop Friday.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barker
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barker







000
FXUS63 KILX 201631
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1031 AM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 1031 AM CST THU NOV 20 2014

Forecast for today on track and only small tweaks to wind gusts
required this morning.

Weak trough pushing southeast over the area has produced a few
clouds south of I-72 particularly areas that still have snow on
the ground. behind the trough, skies are sunny to mostly sunny
allowing some momentum from higher winds several thousand feet off
surface. Have increased wind gusts for today in the grids. Surface
ridge over Mississippi Valley pushes east into Illinois by late
in the day and a drop off in winds and gusts are expected by mid-
afternoon. Diurnal effects should take care of any remnant gusting
by 00z.

Otherwise, current forecast in good shape.

&&

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 530 AM CST THU NOV 20 2014

Another band of mostly VFR cigs was tracking southeast into parts
of west central Illinois early this morning and should affect all
our TAF sites in the next several hours, although the last few
satellite loops indicate the northern edge of the cloud shield
beginning to erode which may keep the bulk of the broken to
overcast cigs south of I-74. Bases of cigs will range from 3000 to
3500 feet with the backedge of cloud deck clearing our area by late
morning or early afternoon as high pressure settles into Midwest.
Other than the clouds tracking thru parts of the area this morning,
the weather should be quiet thru tonight with VFR conditions
expected. Surface winds will be out of the west today at 10 to 15
kts with a few gusts possible up to 20kts this afternoon, especially
at KBMI and KCMI. Winds should become light and variable tonight
as the center of the high shifts over our area.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barker
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith






000
FXUS63 KILX 201631
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1031 AM CST Thu Nov 20 2014

.UPDATE...
ISSUED AT 1031 AM CST THU NOV 20 2014

Forecast for today on track and only small tweaks to wind gusts
required this morning.

Weak trough pushing southeast over the area has produced a few
clouds south of I-72 particularly areas that still have snow on
the ground. behind the trough, skies are sunny to mostly sunny
allowing some momentum from higher winds several thousand feet off
surface. Have increased wind gusts for today in the grids. Surface
ridge over Mississippi Valley pushes east into Illinois by late
in the day and a drop off in winds and gusts are expected by mid-
afternoon. Diurnal effects should take care of any remnant gusting
by 00z.

Otherwise, current forecast in good shape.

&&

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 530 AM CST THU NOV 20 2014

Another band of mostly VFR cigs was tracking southeast into parts
of west central Illinois early this morning and should affect all
our TAF sites in the next several hours, although the last few
satellite loops indicate the northern edge of the cloud shield
beginning to erode which may keep the bulk of the broken to
overcast cigs south of I-74. Bases of cigs will range from 3000 to
3500 feet with the backedge of cloud deck clearing our area by late
morning or early afternoon as high pressure settles into Midwest.
Other than the clouds tracking thru parts of the area this morning,
the weather should be quiet thru tonight with VFR conditions
expected. Surface winds will be out of the west today at 10 to 15
kts with a few gusts possible up to 20kts this afternoon, especially
at KBMI and KCMI. Winds should become light and variable tonight
as the center of the high shifts over our area.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barker
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KLOT 201405
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
805 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE/KMD

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE/KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201405
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
805 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE/KMD

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE/KMD

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 201137
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
537 AM CST Thu Nov 20 2014

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 530 AM CST THU NOV 20 2014

Another band of mostly VFR cigs was tracking southeast into parts
of west central Illinois early this morning and should affect all
our TAF sites in the next several hours, although the last few
satellite loops indicate the northern edge of the cloud shield
beginning to erode which may keep the bulk of the broken to
overcast cigs south of I-74. Bases of cigs will range from 3000 to
3500 feet with the backedge of cloud deck clearing our area by late
morning or early afternoon as high pressure settles into Midwest.
Other than the clouds tracking thru parts of the area this morning,
the weather should be quiet thru tonight with VFR conditions
expected. Surface winds will be out of the west today at 10 to 15
kts with a few gusts possible up to 20kts this afternoon, especially
at KBMI and KCMI. Winds should become light and variable tonight
as the center of the high shifts over our area.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith





000
FXUS63 KILX 201137
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
537 AM CST Thu Nov 20 2014

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.

&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday morning)
ISSUED AT 530 AM CST THU NOV 20 2014

Another band of mostly VFR cigs was tracking southeast into parts
of west central Illinois early this morning and should affect all
our TAF sites in the next several hours, although the last few
satellite loops indicate the northern edge of the cloud shield
beginning to erode which may keep the bulk of the broken to
overcast cigs south of I-74. Bases of cigs will range from 3000 to
3500 feet with the backedge of cloud deck clearing our area by late
morning or early afternoon as high pressure settles into Midwest.
Other than the clouds tracking thru parts of the area this morning,
the weather should be quiet thru tonight with VFR conditions
expected. Surface winds will be out of the west today at 10 to 15
kts with a few gusts possible up to 20kts this afternoon, especially
at KBMI and KCMI. Winds should become light and variable tonight
as the center of the high shifts over our area.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith




000
FXUS63 KLOT 201132
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
532 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201132
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
532 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 201132
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
532 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
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000
FXUS63 KLOT 201132
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
532 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* GUSTY WEST WINDS THROUGH THIS AFTN WITH MAX GUSTS UP TO 25 KT.

JEE

//DISCUSSION...UPDATED 12Z...

A TIGHT PRESSURE GRADIENT REMAINS OVERHEAD SO EXPECTING GUSTY WEST
WINDS AGAIN TODAY. THEY DIMINISH TONIGHT WITH WINDS BECOMING SOUTH
BY FRIDAY AFTERNOON AS HIGH PRESSURE SHIFTS OVER THE OHIO RIVER
VALLEY. DESPITE THE CLEAR CONDITIONS NOW...THINKING A LOW END VFR
STRATOCU DECK WILL DEVELOP LATE THIS MORNING. IT WILL BE A DIURNAL
CLOUD DECK THAT SCATTERS OUT THIS EVENING.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...

FRIDAY NIGHT...SCHC WINTRY MIX BECOMING A CHC OF FREEZING RAIN
OVERNIGHT. IFR CIGS LIKELY. SOUTH WINDS ARND 10 KT.

SATURDAY...CHC -RA/FREEZING RAIN BECOMING RAIN AND FOG OVERNIGHT.
IFR LIKELY. SOUTH-SOUTHWEST WINDS 10-15 KT.

SUNDAY...RAIN. IFR LIKELY. GUSTY SOUTHEAST WINDS.

MONDAY...CHC -RASN BCMG CHC -SN. MVFR CIGS PSBL. STRONG SOUTHWEST
WINDS WITH GUSTS ARND 30 KT PSBL.

TUESDAY...SCHC -SN DURING THE DAY. MVFR CIGS PSBL. GUSTY WEST
WINDS.

WEDNESDAY...VFR. WEST WINDS BCMG SOUTHWEST.

JEE

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KILX 200945
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
345 AM CST Thu Nov 20 2014

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.


&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED NOV 19 2014

Winds have finally diminished as pressure rises slowed down and
the pressure gradient relaxed a bit, especially across the SW half
of IL. We expect west winds in the 8-10kt range for the rest of
the night.

The latest satellite imagery shows diminishing clouds to the W-NW
compared to earlier this evening. We still have a majority of
central IL with some VFR cloud cover in the 3.5k-4.5k ft layer,
but breaks are becoming more numerous with each passing hour. Forecast
soundings remain generally pessimistic with cloud cover the rest of the
night, but we continued with clearing developing at all terminal
sites before sunrise.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 10-145kt range through the day from the
west. Light winds will develop with sunset tomorrow, as winds
decouple under clear skies and weak high pressure.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon






000
FXUS63 KILX 200945
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
345 AM CST Thu Nov 20 2014

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.


&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED NOV 19 2014

Winds have finally diminished as pressure rises slowed down and
the pressure gradient relaxed a bit, especially across the SW half
of IL. We expect west winds in the 8-10kt range for the rest of
the night.

The latest satellite imagery shows diminishing clouds to the W-NW
compared to earlier this evening. We still have a majority of
central IL with some VFR cloud cover in the 3.5k-4.5k ft layer,
but breaks are becoming more numerous with each passing hour. Forecast
soundings remain generally pessimistic with cloud cover the rest of the
night, but we continued with clearing developing at all terminal
sites before sunrise.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 10-145kt range through the day from the
west. Light winds will develop with sunset tomorrow, as winds
decouple under clear skies and weak high pressure.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon







000
FXUS63 KILX 200945
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
345 AM CST Thu Nov 20 2014

.SHORT TERM...(Today)
ISSUED AT 345 AM CST THU NOV 20 2014

Expansive trof aloft still dominating the weather map this
morning.  Cold front has slipped through the area and just south of
the Ohio River Valley this morning.  High pressure building into the
region at the sfc, and plenty of cold air surging back into the
region keeping the max temperatures well below normal again today,
and expected through the end of the week.  Mostly westerly winds
today will be brisk, and with the cold temps expected, the wind
chills will drop into the single digits this morning, and the teens
this afternoon.  Models in pretty good agreement through the
forecast with some minor shifts here and there, but no major changes
to the forecast with this run. Forecast issues revolve around
chances for freezing rain on Friday night, and extensive precip
through the weekend in the form of rain.


&&

.LONG TERM...(Tonight through Wednesday)
ISSUED AT 345 AM CST THU NOV 20 2014

Cold air remains anchored over the region through the end of the
week, though more southerly winds will begin to set up late Friday
in advance of a developing system to the SW. The main issue in the
forecast is the advancement of the rain while the sfc remains below
zero.  Too dry aloft for crystals to support snow, and threat for
fzra is increasing with the precip preceding the warm up at the sfc
after the sun sets Friday evening.  Struggle remains in the models
in the last few runs with regards to timing...and the sfc temps are
now warming very quickly in the GFS.  For now, am throwing out that
concept as the concern remains that it will take longer to erode the
significant cold airmass over frozen ground.  So far, little ice
accumulation is showing in the qpf...with temps struggling near
freezing that night in Central Illinois...as far south as Decatur
through midnight...lingering into the early morning hours. Models
still lacking in timing and the pop spread remains in the forecast
yet again from the slow ECMWF into Mon night/Tues.  Best chances for
the weekend is in the high chance/likely category for precip, though
the temperature profile for now is still indicating rain Saturday
through Sunday, as the low lifts right through the region. With
timing issues, am keeping the likely mention to a minimum with the
exception of the Saturday night/Sunday...which is at least
consistent with 24 hrs ago.  That being said, a gap between the
precip with the warm frontal development and the core of the storm
is developing which may provide a break within that time frame.
Either way...the weekend looks wet, with the majority of the qpf
expected on Sunday, and over an inch storm total expected through
the weekend.  Temps struggling into the 50s will give Central
Illinois a break from the cold for Sunday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED NOV 19 2014

Winds have finally diminished as pressure rises slowed down and
the pressure gradient relaxed a bit, especially across the SW half
of IL. We expect west winds in the 8-10kt range for the rest of
the night.

The latest satellite imagery shows diminishing clouds to the W-NW
compared to earlier this evening. We still have a majority of
central IL with some VFR cloud cover in the 3.5k-4.5k ft layer,
but breaks are becoming more numerous with each passing hour. Forecast
soundings remain generally pessimistic with cloud cover the rest of the
night, but we continued with clearing developing at all terminal
sites before sunrise.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 10-145kt range through the day from the
west. Light winds will develop with sunset tomorrow, as winds
decouple under clear skies and weak high pressure.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Shimon






000
FXUS63 KLOT 200910
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
310 AM CST THU NOV 20 2014

.SHORT TERM...
309 AM CST

TODAY THROUGH SATURDAY...

QUIET WEATHER IN THE NEAR TERM...WITH FOCUS MAINLY ON THE EFFECTS OF
THE STORM SYSTEM WHICH APPROACHES FROM THE SOUTHWEST FRIDAY NIGHT
AND AFFECTS THE REGION THROUGH THE WEEKEND.

LARGE-SCALE UPPER TROUGH OVER THE EASTERN HALF OF NORTH AMERICA WILL
BECOME MORE PROGRESSIVE TODAY...PROPAGATING OFF TO THE EAST COAST
TONIGHT AND FRIDAY. WHILE ANOTHER FAIRLY STRONG MID-LEVEL SHORT WAVE
WILL DIG SOUTHEAST INTO THE TROUGH ACROSS THE GREAT LAKES REGION
TODAY...UPSTREAM SOUNDINGS FROM DVN AND ABR DEPICT VERY DRY AIR IN
MID/UPPER LEVELS WITH MUCH LESS CLOUD COVER THAN IN PREVIOUS DAYS.
SO WHILE IT WILL BE BLUSTERY AND COLD...THERE WILL BE MORE SUNSHINE
THAN WE`VE ENJOYED OF LATE. SURFACE HIGH PRESSURE WILL SPREAD INTO
THE AREA TONIGHT...WITH DIMINISHING WINDS AND MAINLY CLEAR SKIES
PRODUCING ONE MORE CHILLY NIGHT WITH STRONG RADIATIONAL COOLING
CONDITIONS IN LINGERING ARCTIC AIR MASS. TEMPS IN THE 20S TODAY WILL
DROP OFF TO LOWS IN THE SINGLE DIGITS IN MANY AREAS BY FRIDAY
MORNING...THOUGH WITH LIGHT WINDS BY SUNRISE.

THE FLOW ALOFT WILL BECOME MORE WESTERLY FRIDAY...WITH SURFACE WINDS
BECOMING SOUTHERLY AS THE HIGH PRESSURE RIDGE MOVES OFF TO THE EAST
AND SURFACE PRESSURE FALLS DEVELOP ACROSS THE PLAINS. GUIDANCE HAS
BEEN VERY CONSISTENT IN BRINGING A SMALL SHORT WAVE ACROSS THE LOWER
AND MID MISSOURI VALLEY FRIDAY AFTERNOON AND INTO IL FRIDAY NIGHT.
INCREASING SOUTHWESTERLY WINDS ABOVE THE SURFACE...AND RESULTING
WARM/MOIST ADVECTION AND ISENTROPIC ASCENT...WILL BRING THE
POTENTIAL FOR LIGHT PRECIPITATION TO DEVELOP NORTHWARD INTO THE
FORECAST AREA FRIDAY NIGHT. THIS PRESENTS A PROBLEM...AS
TEMPERATURES WARM MORE QUICKLY ALOFT AND SETS THE STAGE FOR A PERIOD
OF LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING
BEFORE SURFACE TEMPERATURES RISE ABOVE FREEZING. FORECAST SOUNDINGS
INDICATE ELEVATED WARM LAYER TEMPS OF +3 TO +7 DEGREES DEVELOP ABOVE
A 1000-1500 FOOT LAYER OF SUB-FREEZING AIR AT THE SURFACE...MAKING
FREEZING RAIN AND PERHAPS A LITTLE LIGHT SLEET THE LIKELY INITIAL
PRECIP TYPE. VARIOUS MODELS IN PRETTY GOOD AGREEMENT IN DEPICTING
SURFACE TEMPS WARMING TO/ABOVE FREEZING GENERALLY ALONG/SOUTH OF THE
I-80 CORRIDOR OVERNIGHT...WITH AREAS FARTHER NORTH RISING ABOVE
FREEZING DURING THE MORNING HOURS. WHILE QPF AMOUNTS ARE LIGHT WITH
ONLY A FEW HUNDREDTHS PRODUCED...ANY ICE ACCUMULATION WILL LIKELY
MAKE FOR SOME SLIPPERY TRAVEL CONDITIONS AS GLAZE FORMS ON SOME
ROADS AND MANY PARKING LOTS AND SIDEWALKS. TEMPS ARE EXPECTED TO
RISE INTO THE 40S CWA-WIDE BY AFTERNOON HOWEVER...WITH ANY LINGERING
LIGHT PRECIP FALLING AS SOME OCCASIONAL LIGHT RAIN DURING THE DAY.

RATZER

&&

.LONG TERM...
309 AM CST

SUNDAY THROUGH WEDNESDAY...

MEANWHILE...A FAIRLY VIGOROUS UPPER TROUGH WILL HAVE MOVED ASHORE
ACROSS THE SOUTHWESTERN STATES...AND IS PROGGED TO MOVE EAST INTO
TEXAS THROUGH SATURDAY AFTERNOON BEFORE EJECTING NORTHEASTWARD AS A
STRONG NEGATIVE-TILT SHORT WAVE LATER SATURDAY NIGHT AND SUNDAY.
MODELS CONTINUE TO DEPICT AN ASSOCIATED RAPIDLY DEEPENING AREA OF
SURFACE LOW PRESSURE LIFTING INTO NORTHERN ILLINOIS BY LATE SUNDAY
AFTERNOON. CONTINUED LOW/MID LEVEL MOIST ADVECTION COUPLED WITH
INCREASING LARGE SCALE ASCENT AHEAD OF THE APPROACHING LOW LOOKS TO
PRODUCE FAIRLY SIGNIFICANT RAINFALL ACROSS THE AREA SUNDAY...WITH
MODELS GENERALLY INDICATING AMOUNTS APPROACHING 1.00" BEFORE RAIN
TAPERS OFF SUNDAY NIGHT AS THE LOW LIFTS NORTH OF THE AREA. THIS
WILL HAVE TO BE WATCHED AS GROUND IS CURRENTLY FROZEN...AT LEAST IN
THE TOP FEW INCHES...WHICH MAY RESULT IN SOME RUN-OFF PROBLEMS WITH
SOME FLOODING POTENTIAL AND QUICK RIVER/CREEK RISES.

MODELS CONTINUE TO INDICATE A MERGING OF THE SHORT WAVE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE UPPER MISSISSIPPI VALLEY
SUNDAY NIGHT...WITH THE LOW CONTINUING TO DEEPEN TO BELOW 980 MB
ACROSS THE NORTHERN LAKES BY 12Z MONDAY. VERY WINDY CONDITIONS LOOK
TO DEVELOP FROM THE WEST IN THE TIGHT GRADIENT ASSOCIATED WITH THE
DEEPENING LOW...WITH 35-40 MPH GUSTS POSSIBLE MONDAY. AS COLDER AIR
GETS PULLED INTO THE REGION ON THESE GUSTY WEST WINDS...ANY
LINGERING LIGHT PRECIP WILL TRANSITION FROM LIGHT RAIN TO RAIN/SNOW
ACROSS THE WESTERN CWA BY EARLY MONDAY MORNING...AND TO LIGHT SNOW
SHOWERS ACROSS THE AREA MONDAY NIGHT INTO TUESDAY AS A SERIES OF
SHORT WAVES ROTATE ABOUT THE CLOSED LOW TO OUR NORTH. 00Z RUNS OF
BOTH THE GFS AND ECMWF KICK THE TROUGH OFF TO THE EAST TUESDAY NIGHT
INTO WEDNESDAY...WITH WEAK SURFACE HIGH PRESSURE BRINGING DRY
WEATHER AND DECREASING WINDS BY MID-WEEK...THOUGH WITH CONTINUED
BELOW-NORMAL TEMPS.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* GUSTY WEST WINDS REDEVELOP THIS MORNING AND PERSIST THROUGH
  THIS AFTN WITH MAX GUSTS ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO







000
FXUS63 KLOT 200856
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
256 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* GUSTY WEST WINDS REDEVELOP THIS MORNING AND PERSIST THROUGH
  THIS AFTN WITH MAX GUSTS ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200856
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
256 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 09Z...

* GUSTY WEST WINDS REDEVELOP THIS MORNING AND PERSIST THROUGH
  THIS AFTN WITH MAX GUSTS ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 09Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 200822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
222 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 200822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
222 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 200822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
222 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 200822
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
222 AM CST THU NOV 20 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
221 AM CST

HEADLINES...WILL CONTINUE THE OPEN WATER GALE WARNING INTO THIS
MORNING AS WELL AS THE SMALL CRAFT ADVISORY THROUGH FRIDAY. WINDS
AND WAVES WILL PROBABLY COME DOWN BEFORE THE END OF THE SMALL CRAFT
ADVSY...BUT WILL LEAVE IT AS IS FOR NOW. ISSUED YET ANOTHER GALE
WATCH FOR SATURDAY EVENING THROUGH MID SATURDAY MORNING FOR THE
NORTHERN 2/3 OF THE LAKE. GALES ARE ALSO POSSIBLE LATE SUNDAY NIGHT
THROUGH MONDAY NIGHT AS A LOW PRESSURE SYSTEM SLIDES UP THE
LAKE...BUT IT IS TOO SOON TO ISSUE A HEADLINE NOW. ANOTHER SMALL
CRAFT ADVISORY MAY ALSO BE NEEDED FRIDAY NIGHT INTO SATURDAY NIGHT
AND AGAIN SUNDAY THROUGH AT LEAST TUESDAY NIGHT. MAY HAVE TO EXTEND
IT INTO WEDNESDAY IF WAVES TAKE LONGER TO SUBSIDE.

LOW PRESSURE IS OVER SOUTHEAST ONTARIO WHILE HIGH PRESSURE STRETCHES
FROM THE NORTHERN PLAINS THROUGH THE SOUTHEAST U.S. WEST WINDS WILL
DIMINISH TO BELOW GALE FORCE THIS MORNING.  THEN THE HIGH PASSES
SOUTH OF THE LAKE LATE TONIGHT WITH WINDS CONTINUING TO DIMINISH AND
BECOME SOUTH TO SOUTHWEST BEHIND THE HIGH.  A LOW PRESSURE SYSTEM
PASSES OVER CENTRAL MANITOBA TONIGHT REACHING HUDSON BAY SATURDAY
MORNING. THE PRESSURE GRADIENT TIGHTENS BETWEEN THE LOW AND
DEPARTING HIGH WHICH MAY LEAD TO GALE FORCE GUSTS OVER THE NORTHERN
2/3 OF THE LAKE.

SOUTHWEST WINDS DIMINISH SATURDAY AND BECOME SOUTHEAST AHEAD OF THE
NEXT SYSTEM. A LARGE LOW SPREADS OVER THE PLAINS SUNDAY MORNING AND
FORMS A CLOSED LOW OVER NORTHERN IL SUNDAY EVENING. GUIDANCE STILL
DIFFERS ON THE EXACT STRENGTH AND PATH OF THIS LOW...BUT BOTH MODELS
INDICATE THE LOW WILL DEEPEN TO AROUND 975 MB/28.8 INCHES AT THE
NORTH END OF THE LAKE MONDAY AFTERNOON.  EXPECTING SOUTHEAST WINDS
TO INCREASE TO AT LEAST 30 KT THROUGH SUNDAY EVENING AND THEN BECOME
SOUTHWEST BEHIND THE LOW.  GALES ARE EXPECTED BY LATE SUNDAY NIGHT
AND DEPENDING ON THE PATH AND STRENGTH OF THE LOW...STORM FORCE
WINDS MAY BE INCLUDED IN FUTURE FORECASTS. GUIDANCE INDICATED A
BRIEF PERIOD OF HIGH END GALES OVER THE NORTHERN END OF THE LAKE
MONDAY AFTERNOON SO KEPT WINDS IN THE GALE RANGE FOR NOW.  THE LOW
MOVES OVER QUEBEC TUESDAY WITH WEST WINDS DIMINISHING TO BELOW GALES
EARLY TUESDAY MORNING. HIGH PRESSURE MOVES OVER THE LAKE MID NEXT
WEEK HOPEFULLY BRINGING WITH A MUCH NEEDED BREAK.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
     LMZ669-LMZ868-LMZ870...6 PM FRIDAY TO 9 AM SATURDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KILX 200543
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1143 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 900 PM CST WED NOV 19 2014

Flurries continue to affect much of central IL this evening under
a weak shortwave in the strong W-NW flow. A band of low clouds
associated with the feature will persist the rest of the evening
and most likely well after midnight before dry air above the cloud
layer creates some clearing. Satellite images show breaks in the
clouds upstream, so periods of clearing should progress across the
area later tonight. That clearing and some decrease in wind speeds
should help low temps dip to forecast numbers in the mid-upper
teens by sunrise Thursday. W-NW winds of 8-12 mph will push wind
chill readings down into the single digits after midnight.

High pressure will advance east into IL on Thursday, providing
mostly clear skies and continued cold conditions. However, winds
should be lighter under the ridge axis and weaker pressure gradient.

Updates this evening were mainly to the sky grids to match
expected trends. We kept clouds around longer after midnight, but
still expect clearing for tomorrow morning. Updated info is
already available.

&&

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFS and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
Sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED NOV 19 2014

Winds have finally diminished as pressure rises slowed down and
the pressure gradient relaxed a bit, especially across the SW half
of IL. We expect west winds in the 8-10kt range for the rest of
the night.

The latest satellite imagery shows diminishing clouds to the W-NW
compared to earlier this evening. We still have a majority of
central IL with some VFR cloud cover in the 3.5k-4.5k ft layer,
but breaks are becoming more numerous with each passing hour. Forecast
soundings remain generally pessimistic with cloud cover the rest of the
night, but we continued with clearing developing at all terminal
sites before sunrise.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 10-145kt range through the day from the
west. Light winds will develop with sunset tomorrow, as winds
decouple under clear skies and weak high pressure.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 200543
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1143 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 900 PM CST WED NOV 19 2014

Flurries continue to affect much of central IL this evening under
a weak shortwave in the strong W-NW flow. A band of low clouds
associated with the feature will persist the rest of the evening
and most likely well after midnight before dry air above the cloud
layer creates some clearing. Satellite images show breaks in the
clouds upstream, so periods of clearing should progress across the
area later tonight. That clearing and some decrease in wind speeds
should help low temps dip to forecast numbers in the mid-upper
teens by sunrise Thursday. W-NW winds of 8-12 mph will push wind
chill readings down into the single digits after midnight.

High pressure will advance east into IL on Thursday, providing
mostly clear skies and continued cold conditions. However, winds
should be lighter under the ridge axis and weaker pressure gradient.

Updates this evening were mainly to the sky grids to match
expected trends. We kept clouds around longer after midnight, but
still expect clearing for tomorrow morning. Updated info is
already available.

&&

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFS and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
Sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1143 PM CST WED NOV 19 2014

Winds have finally diminished as pressure rises slowed down and
the pressure gradient relaxed a bit, especially across the SW half
of IL. We expect west winds in the 8-10kt range for the rest of
the night.

The latest satellite imagery shows diminishing clouds to the W-NW
compared to earlier this evening. We still have a majority of
central IL with some VFR cloud cover in the 3.5k-4.5k ft layer,
but breaks are becoming more numerous with each passing hour. Forecast
soundings remain generally pessimistic with cloud cover the rest of the
night, but we continued with clearing developing at all terminal
sites before sunrise.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 10-145kt range through the day from the
west. Light winds will develop with sunset tomorrow, as winds
decouple under clear skies and weak high pressure.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Shimon







000
FXUS63 KLOT 200530
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1130 PM CST WED NOV 19 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200530
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1130 PM CST WED NOV 19 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200530
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1130 PM CST WED NOV 19 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200530
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1130 PM CST WED NOV 19 2014

.UPDATE...854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 06Z...

* GUSTY WEST WINDS CONTINUE THROUGH TOMORROW AFTN WITH MAX GUSTS
  ARND 21 KT.

JEE

//DISCUSSION...UPDATED 06Z...

HIGH PRESSURE IS TO OUR WEST AND IT WILL PASS TO THE SOUTH THIS
EVENING. THE PRESSURE GRADIENT REMAINS TIGHT BETWEEN THE HIGH AND
A LOW OVER SOUTHEAST ONTARIO...SO EXPECTING GUSTY WEST WINDS TO
CONTINUE THROUGH THIS AFTERNOON. THE GRADIENT WEAKENS AS THE
HIGH PASSES TO THE SOUTH THIS EVENING. MAY EVEN SEE WINDS BECOME
LIGHT AND VARIABLE TO EVEN CALM LATE TONIGHT.

FOR CIGS DID NOT MAKE MANY CHANGES AS A PERIOD OF LOW END VFR CIGS
ARE POSSIBLE DURING THE DAY. THEY WILL SCATTER OUT IN THE EVENING
WITH SCT OR LESS CLOUDS TONIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 06Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 200305
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 900 PM CST WED NOV 19 2014

Flurries continue to affect much of central IL this evening under
a weak shortwave in the strong W-NW flow. A band of low clouds
associated with the feature will persist the rest of the evening
and most likely well after midnight before dry air above the cloud
layer creates some clearing. Satellite images show breaks in the
clouds upstream, so periods of clearing should progress across the
area later tonight. That clearing and some decrease in wind speeds
should help low temps dip to forecast numbers in the mid-upper
teens by sunrise Thursday. W-NW winds of 8-12 mph will push wind
chill readings down into the single digits after midnight.

High pressure will advance east into IL on Thursday, providing
mostly clear skies and continued cold conditions. However, winds
should be lighter under the ridge axis and weaker pressure gradient.

Updates this evening were mainly to the sky grids to match
expected trends. We kept clouds around longer after midnight, but
still expect clearing for tomorrow morning. Updated info is
already available.

&&

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFS and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
Sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 559 PM CST WED NOV 19 2014

Strong W/NW winds will highlight the early TAF forecast as gusts
to 30kt still showing up from PIA to BMI. Pressure rises of 2-3mb
per 3-hours will continue through around 3z/9pm behind the cold
front, so will continue gusts at all terminal sites through that
time. After that, pressure rises slow down, but a continued
pressure gradient across the NE half of IL will help keep
sustained winds in the 12-15kt range for at least the northern
terminals of PIA/BMI/CMI.

2330z/530pm satellite imagery shows breaks in the low cloud cover
upstream across Iowa and S MN, but a channel of clouds from W Iowa
back into SD/ND streaming toward SPI and DEC. Forecast soundings
are generally pessimistic with cloud cover through the night, but
still expect some clearing to develop later tonight. Most cloud
cover will be VFR anyway, so the clearing will not be a major
change in flight category. However, ceilings are hovering right
around 3k ft near PIA/BMI, so a brief period of MVFR cloud heights
can not be ruled out there.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 12-15kt range through the day from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KILX 200305
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 900 PM CST WED NOV 19 2014

Flurries continue to affect much of central IL this evening under
a weak shortwave in the strong W-NW flow. A band of low clouds
associated with the feature will persist the rest of the evening
and most likely well after midnight before dry air above the cloud
layer creates some clearing. Satellite images show breaks in the
clouds upstream, so periods of clearing should progress across the
area later tonight. That clearing and some decrease in wind speeds
should help low temps dip to forecast numbers in the mid-upper
teens by sunrise Thursday. W-NW winds of 8-12 mph will push wind
chill readings down into the single digits after midnight.

High pressure will advance east into IL on Thursday, providing
mostly clear skies and continued cold conditions. However, winds
should be lighter under the ridge axis and weaker pressure gradient.

Updates this evening were mainly to the sky grids to match
expected trends. We kept clouds around longer after midnight, but
still expect clearing for tomorrow morning. Updated info is
already available.

&&

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFS and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
Sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 559 PM CST WED NOV 19 2014

Strong W/NW winds will highlight the early TAF forecast as gusts
to 30kt still showing up from PIA to BMI. Pressure rises of 2-3mb
per 3-hours will continue through around 3z/9pm behind the cold
front, so will continue gusts at all terminal sites through that
time. After that, pressure rises slow down, but a continued
pressure gradient across the NE half of IL will help keep
sustained winds in the 12-15kt range for at least the northern
terminals of PIA/BMI/CMI.

2330z/530pm satellite imagery shows breaks in the low cloud cover
upstream across Iowa and S MN, but a channel of clouds from W Iowa
back into SD/ND streaming toward SPI and DEC. Forecast soundings
are generally pessimistic with cloud cover through the night, but
still expect some clearing to develop later tonight. Most cloud
cover will be VFR anyway, so the clearing will not be a major
change in flight category. However, ceilings are hovering right
around 3k ft near PIA/BMI, so a brief period of MVFR cloud heights
can not be ruled out there.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 12-15kt range through the day from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Shimon







000
FXUS63 KLOT 200303
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
903 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* CHANCE FOR TEMPORARY MVFR CIGS OVERNIGHT.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* HIGH THAT IF ANY MVFR CIGS OCCUR OVERNIGHT THEY WILL BE ABOVE
  2000 FT AND TEMPORARY.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200303
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
903 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* CHANCE FOR TEMPORARY MVFR CIGS OVERNIGHT.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* HIGH THAT IF ANY MVFR CIGS OCCUR OVERNIGHT THEY WILL BE ABOVE
  2000 FT AND TEMPORARY.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200303
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
903 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* CHANCE FOR TEMPORARY MVFR CIGS OVERNIGHT.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* HIGH THAT IF ANY MVFR CIGS OCCUR OVERNIGHT THEY WILL BE ABOVE
  2000 FT AND TEMPORARY.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200303
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
903 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 03Z...

* CHANCE FOR TEMPORARY MVFR CIGS OVERNIGHT.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 03Z...

* HIGH THAT IF ANY MVFR CIGS OCCUR OVERNIGHT THEY WILL BE ABOVE
  2000 FT AND TEMPORARY.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200256
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
856 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.

//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 200256
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
856 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.

//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 200256
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
856 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.

//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
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000
FXUS63 KLOT 200256
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
856 PM CST WED NOV 19 2014

.UPDATE...
854 PM CST

SNOW SHOWER ACTIVITY WILL BE EXITING THE AREA OVER THE NEXT FEW
HOURS WITH SATELLITE SHOWING SOME SUBSTANTIAL GAPS DEVELOPING IN
THE OVERCAST TO THE WEST AND NORTH. EXPECT THAT THERE WILL BE A
PERIOD OF SCATTERING/CLEARING INTO THE EARLY OVERNIGHT BEFORE
ANOTHER AREA OF CLOUD COVER CURRENTLY OVER THE MN/WI BORDER REGION
WORKS SOUTHEAST ACROSS NORTHEASTERN PORTIONS OF THE AREA.
SOUTHWEST AREAS SHOULD SEE MORE PERIODIC GAPS IN COVERAGE
OVERNIGHT. MAINTAINED LOW TEMPS THOUGH ADJUSTED HOURLY TRENDS WITH
CLEARING LIKELY BRINGING A QUICK FEW DEGREE DROP BASED ON UPSTREAM
TRENDS...BUT STEADY WINDS WILL LIMIT MORE OF A DROP.

MDB

&&

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.

//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.

//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.

//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 200000
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
600 PM CST Wed Nov 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.

&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFS and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
Sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
ISSUED AT 559 PM CST WED NOV 19 2014

Strong W/NW winds will highlight the early TAF forecast as gusts
to 30kt still showing up from PIA to BMI. Pressure rises of 2-3mb
per 3-hours will continue through around 3z/9pm behind the cold
front, so will continue gusts at all terminal sites through that
time. After that, pressure rises slow down, but a continued
pressure gradient across the NE half of IL will help keep
sustained winds in the 12-15kt range for at least the northern
terminals of PIA/BMI/CMI.

2330z/530pm satellite imagery shows breaks in the low cloud cover
upstream across Iowa and S MN, but a channel of clouds from W Iowa
back into SD/ND streaming toward SPI and DEC. Forecast soundings
are generally pessimistic with cloud cover through the night, but
still expect some clearing to develop later tonight. Most cloud
cover will be VFR anyway, so the clearing will not be a major
change in flight category. However, ceilings are hovering right
around 3k ft near PIA/BMI, so a brief period of MVFR cloud heights
can not be ruled out there.

Once the skies clear out, we expect enough dry air mixing tomorrow
to prevent any BKN cloud decks from forming, but moisture will
remain in the 2-3k ft layer according to forecast moisture
profiles. Winds will be less gusty than today, but sustained winds
will climb back into the 12-15kt range through the day from the west.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Shimon






000
FXUS63 KLOT 192349
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
549 PM CST WED NOV 19 2014

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 192349
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
549 PM CST WED NOV 19 2014

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 00Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH 02Z-03Z LEADING TO TEMPORARY
  REDUCTIONS TO MVFR VISIBILITY.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 03Z.


//DISCUSSION...UPDATED 00Z...

THE WEATHER EXPERIENCED THIS AFTERNOON...THAT IS GUSTY WESTERLY
WINDS...CLOUDY...AND FLURRIES...WILL BASICALLY CONTINUE THROUGH
EARLY-MID EVENING DUE TO THE COLD AIR ADVECTION PATTERN REMAINING
IN PLACE. ISOLATED SNOW SHOWERS WITH MVFR VISIBILITY ARE NOTED
ACROSS NORTHEAST IL BUT ANY 4-5SM VISIBILITY AT THE AIRPORTS SHOULD
BE BRIEF. SCATTERING AND LIFTING OF CLOUDS ARE SEEN UPSTREAM ON
EARLY EVENING SATELLITE IMAGERY AND WOULD EXPECT THAT TO MOVE OVER
THE AREA OVERNIGHT. GIVEN THE COLD AIR ALOFT TO START THURSDAY
WOULD EXPECT TO SEE A FILLING IN OF CLOUDS BY MID-LATE MORNING.
WITH HIGH PRESSURE MOVING OVER THURSDAY NIGHT...THE SKY SHOULD
TREND TOWARD CLEARING AND WIND SPEEDS WILL FINALLY COME DOWN AFTER
ANOTHER GUSTY DAY THURSDAY.


//ORD AND MDW CONFIDENCE...UPDATED 00Z...

* HIGH IN FLURRIES/LIGHT SNOW SHOWER TIMING AND THAT ANY REDUCTION
  IN VISIBILITY WILL BE BRIEF.

* HIGH IN WIND FORECAST.


//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...

FRIDAY...CHANCE FOR LIGHT FREEZING PRECIP AND/OR ICE PELLETS LATE
          EVENING AND OVERNIGHT. SOUTH WINDS.
SATURDAY...PERIODS OF RAIN AND DRIZZLE LIKELY WITH FOG DEVELOPING
           DURING THE NIGHT. AT LEAST TEMPORARY IFR LIKELY.
           SOUTH-SOUTHWEST WINDS.
SUNDAY...IFR AND RAIN. GUSTY SOUTHEAST WINDS.
MONDAY...CHANCE OF RAIN AND SNOW. MVFR POSSIBLE. STRONG SOUTHWEST
         WINDS.
TUESDAY...CHANCE OF LIGHT SNOW. MVFR POSSIBLE. WEST WINDS.

MTF

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 192150
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
350 PM CST WED NOV 19 2014

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH AT LEAST EARLY EVENING.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 00Z-01Z.

MTF


//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH IN NON ACCUMULATING FLURRIES/LIGHT SNOW SHOWERS THROUGH
  EARLY THIS EVENING. HIGH THAT ANY MVFR VISIBILITY WILL BE BE
  BRIEF AND THAT CEILINGS WILL REMAIN 2500-4000 FT.

* HIGH IN WIND TRENDS.

MTF


//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 192150
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
350 PM CST WED NOV 19 2014

.SHORT TERM...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 22Z...

* FLURRIES/LIGHT SNOW SHOWERS THROUGH AT LEAST EARLY EVENING.

* GUSTY WESTERLY WINDS THROUGH A LARGE PORTION OF THE TAF...WITH
  THE HIGHEST GUSTS OF 25-30 KT THROUGH 00Z-01Z.

MTF


//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD


//ORD AND MDW CONFIDENCE...UPDATED 22Z...

* HIGH IN NON ACCUMULATING FLURRIES/LIGHT SNOW SHOWERS THROUGH
  EARLY THIS EVENING. HIGH THAT ANY MVFR VISIBILITY WILL BE BE
  BRIEF AND THAT CEILINGS WILL REMAIN 2500-4000 FT.

* HIGH IN WIND TRENDS.

MTF


//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 192100
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 PM CST WED NOV 19 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 192100
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 PM CST WED NOV 19 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY...

300 PM...COLD FRONT WELL EAST OF THE AREA THIS AFTERNOON WITH
SCATTERED LIGHT SNOW SHOWERS AND FLURRIES AS ANOTHER PUNCH OF
COLDER AIR SPREADS ACROSS THE REGION WITH SLOWLY FALLING TEMPS
THIS AFTERNOON. EXTENSIVE CLOUD COVER BACK THROUGH THE UPPER
MIDWEST AND EXPECT MOSTLY CLOUDY SKIES INTO THE OVERNIGHT HOURS
WITH SOME SCATTERING ACROSS THE SOUTHWEST TOWARD MORNING. FLURRIES
AND FEW SNOW SHOWERS WILL ALSO CONTINUE THIS EVENING AND POSSIBLY
INTO THE OVERNIGHT HOURS BUT ONLY A DUSTING...AT THE MOST...WILL
BE POSSIBLE IN SOME LOCATIONS.

WINDS HAVE ALSO INCREASED WITH GUSTS 35 TO 40 MPH IN MANY
LOCATIONS. THE STRONGEST WINDS WILL DIMINISH WITH SUNSET...BUT IT
WILL STILL REMAIN QUITE BLUSTERY THROUGH THE EVENING WITH WINDS
STILL IN THE 10-15 MPH OVERNIGHT. THESE WINDS COMBINED WITH THE
EXPECTED CLOUD COVER WILL LIKELY KEEP LOW TEMPS IN THE TEENS BY
MORNING...THOUGH WIND CHILLS WILL BE AROUND ZERO.

STILL BREEZY ON THURSDAY WITH HIGHS STRUGGLING INTO THE MID 20S
WITH A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA THURSDAY
NIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS...TEMPS WILL
LIKELY TANK WITH LOWS IN THE SINGLE DIGITS IN MANY LOCATIONS BY
FRIDAY MORNING. WINDS TURN LIGHT SOUTHERLY FRIDAY AS THE HIGH
DEPARTS WITH TEMPS REBOUNDING BACK INTO THE UPPER 20S TO NEAR 30
ACROSS THE SOUTH WITH SOME SUNSHINE AT LEAST THRU EARLY AFTERNOON.
CMS

&&

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY...

300 PM...MULTIPLE FORECAST CONCERNS AND CHALLENGES INCLUDING
FREEZING RAIN FRIDAY NIGHT/EARLY SATURDAY MORNING...POSSIBLE
HEAVY RAIN SUNDAY...FOG SATURDAY NIGHT INTO SUNDAY...THEN
POSSIBLE VERY STRONG WINDS SUNDAY NIGHT INTO MONDAY.

BROAD WEAK LIFT COMBINED WITH STRONG WARM AIR ADVECTION WILL
ALLOW LIGHT PRECIPITATION TO BEGIN FALLING FRIDAY EVENING...FROM
SOUTH TO NORTH ACROSS THE AREA. AFTER A WEEK AND A HALF OF MAINLY
SUB FREEZING TEMPS AND HIGH TEMPS NOT EXPECTED TO REACH FREEZING
FRIDAY AFTERNOON...IN ADDITION TO VERY DRY LOW LEVELS...SURFACES
AND SURFACE TEMPERATURES WILL BE BELOW FREEZING AS PRECIPITATION
BEGINS FRIDAY EVENING. SOUNDINGS SHOW A VERY DEEP WARM LAYER SO
WHILE THERE COULD BE A LITTLE SLEET AT ONSET...BULK OF PRECIP
SHOULD BE LIGHT FREEZING RAIN.

RATHER GOOD CONSISTENCY FROM THE GEM/GFS/ECMWF OF BOTH TEMPS AND
DEWPOINTS SLOWLY BUT STEADILY RISING LATE FRIDAY NIGHT INTO EARLY
SATURDAY MORNING AND HAVE THE FREEZING LINE TO ABOUT THE I-80
CORRIDOR BY 12Z SATURDAY MORNING...WHICH IS ACTUALLY SLOWER/COLDER
THAN THESE MODELS. THE NAM KEEPS TEMPS WELL BELOW FREEZING INTO
MID MORNING SATURDAY AND CONSIDERING WINDS ARE ALL SOUTHERLY
DURING THIS EVENT...WARMER/MORE MOIST AIR MIGHT ARRIVE SOONER
RATHER THAN LATER. NEVERTHELESS...ANY AMOUNT OF ICING WILL CAUSE
SIGNIFICANT PROBLEMS...SO AS THIS TIME PERIOD APPROACHES...THESE
TRENDS WILL BECOME MORE IMPORTANT FOR PRECIP TIMING/DURATION.

AS TEMPS AND DEWPOINTS CONTINUE TO INCREASE SATURDAY...HIGHS MAY
REACH THE MID 40S BUT WILL LIKELY BE ACCOMPANIED BY PERIODS OF
LIGHT RAIN OR DRIZZLE. WITH NO CHANGES SATURDAY NIGHT...THIS MOIST
AIR OVER THE COLD GROUND WILL LIKELY RESULT IN FOG AND ADDED THIS
TO THE FORECAST. HOW DENSE IT BECOMES OR HOW LONG IT PERSISTS IS
A BIT UNCERTAIN THOUGH.

LOW PRESSURE WILL DEVELOP OVER THE SOUTHERN PLAINS SATURDAY NIGHT
AND TURN NORTH AND DEEPEN AS IT REACHES NORTHERN IL SUNDAY
AFTERNOON INTO SUNDAY EVENING. THE LOW CONTINUES TO DEEPEN TO AS
LOW AS 973MB BY MONDAY MORNING OVER NORTHEAST WI AS SHOWN BY THE
12Z GFS/ECMWF. WHILE PLENTY WARM ENOUGH FOR NO WINTER PRECIP
CONCERNS AS IT MOVES ACROSS THE AREA...THE TRACK WILL BE IMPORTANT
REGARDING WHERE THE HEAVIEST RAINS FALL. PRECIPITABLE WATER VALUES
REACH INTO THE 1.0 TO 1.2 INCH RANGE BY SUNDAY AFTERNOON ALONG
WITH EVENT TOTAL QPF FROM THE MODELS IN THE 1 TO 2 INCH RANGE OVER
PARTS OF THE REGION...ESPECIALLY TO THE WEST AND SOUTHWEST. TOO
EARLY FOR SPECIFIC RAINFALL AMOUNTS...BUT GIVEN THE AMOUNT OF
MOISTURE TO WORK WITH...HEAVY RAINFALL WILL BE A POSSIBILITY AND
IF THIS DOES MATERIALIZE...IT WILL BE FALLING ONTO FROZEN OR
PARTIALLY FROZEN GROUND. THUS...AS THIS TIME PERIOD APPROACHES...
HYDRO ISSUES MAY BECOME A CONCERN.

AFTER THE LOW PASSES...FORECAST SOUNDINGS SUGGEST VERY STRONG
WINDS AND GUSTS MAY DEVELOP SUNDAY NIGHT AND CONTINUE MONDAY AND
MONDAY NIGHT. AS COLDER AIR SPREADS ACROSS THE REGION SUNDAY NIGHT
INTO MONDAY...LINGERING LIGHT RAIN WILL MIX WITH THEN CHANGE TO
LIGHT SNOW. WHILE THE DETAILS ARE STILL SEVERAL DAYS AWAY...THERE
DOES APPEAR TO BE SOME POTENTIAL FOR LIGHT SNOW OR SNOW SHOWERS BY
MONDAY AFTERNOON INTO MONDAY EVENING. COLD AND BELOW NORMAL TEMPS
WILL THEN CONTINUE THROUGH MID WEEK. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 192055
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CST Wed Nov 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.


&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFs and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.


&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Barnes







000
FXUS63 KILX 192055
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CST Wed Nov 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.


&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFs and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.


&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Barnes







000
FXUS63 KILX 192055
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CST Wed Nov 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.


&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFs and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.


&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Barnes







000
FXUS63 KILX 192055
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
255 PM CST Wed Nov 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 254 PM CST WED NOV 19 2014

Breezy and cold weather will be the rule across central Illinois
tonight.  19z/1pm surface analysis shows cold front exiting into
Indiana, while ridge of high pressure builds into the Plains.
Pressure gradient between these two features will continue to create
W/NW wind gusts of 25 to 35 mph this afternoon.  Gustiness will
begin to subside toward sunset: however, with ridge axis staying
west of Illinois until Thursday, gradient will remain tight enough
to support winds of around 10 mph through the night.  Clouds and a
few flurries will prevail early in the evening, with the big weather
question being how fast skies will clear later tonight.  Widespread
cloud cover is currently evident on satellite imagery from Illinois
northwestward to the US/Canada border: however, several holes in the
overcast have developed upstream across the Dakotas/Minnesota.  All
model guidance suggests clouds will begin to scatter this evening,
with mostly clear conditions expected overnight.  Given current
satellite imagery and continued deep northwesterly flow, think this
is too fast.  Have therefore gone with a slower clearing trend more
in line with the HRRR solution.  End result will be cloudy skies
this evening, followed by gradual clearing overnight.  Due to the
clouds and continued breeze, have gone with the higher end of
numeric guidance for lows tonight, with readings ranging from 14
degrees in Galesburg to around 20 degrees south of I-70.


&&

.LONG TERM...(Thursday through Wednesday)
ISSUED AT 254 PM CST WED NOV 19 2014

Moisture channel satellite imagery and the morning upper air shows
deep upper level trof over eastern US with main jet from central
Canada into the midwest. This upper flow will bring in another surge
of cold air, with cold surface high moving into region during the
day Thursday and Thursday night. With clear skies by Thursday night,
have lowered Friday morning lows some due to light winds and cold
airmass.

Main precipitation concern is for Friday evening and Friday night,
as overrunning precipitation develops from AR into MO ahead of
digging shortwave in the southwest US. Precipitation will reach
central IL Friday evening, so temperature forecast will be critical,
as warm air aloft will produce precipitation in form of rain.

A detailed look at the model surface temperature forecasts depicts
EUR warmest, GFS, and NAM coolest. Feel the warming temperatures
will be blend of GFs and NAM, as conditions will start off cooler
Friday morning, as lowered morning lows. Feel current forecast grids
a good compromise and so looks like pcpn will start in evening
Friday as light freezing rain, with the freezing line gradually
moving to the northeast overnight. Pcpn amounts still look to be
light, so impacts will be on the light scale.

Saturday pcpn will be rain, as overrunning pcpn continues to develop
and move into the region. Strongest dynamics look to be on Sunday,
as the shortwave system and surface low approach and move through
region.

Models are similar in the movement of system, with low center
tracking just west of the cwa Sunday, with front moving through area
and gusty winds. Vertical stacking of the upper low over Lake MI on
sunday night.

Cool conditions will conditions into midweek, as the upper low
gradually moves off and allows another cool high pressure area into
the midwest.


&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...Barnes
LONG TERM...Goetsch
AVIATION...Barnes







000
FXUS63 KLOT 191951
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
151 PM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 191951
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
151 PM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 191951
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
151 PM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 191951
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
151 PM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 20Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR
  CIGS/VSBY AT TIMES.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 20Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST...BUT THIS FAR SOUTH
VSBYS HAVE STRUGGLED TO GET LOWER THAN 5 SM. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS THIS AFTERNOON.
IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH AND EAST...BUT WE
WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL SUPPORT SOME LIGHT
SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE LIGHT AND NON
ACCUMULATING DUE TO THE GUSTY WEST WINDS WITH LARGELY LOW END VFR
CONDITIONS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 20Z...

* HIGH IN A PERIOD OF NON ACCUMULATING SNOW SHOWERS THIS AFTERNOON
  WITH FLURRIES POSSIBLE INTO THE EVENING. MEDIUM THAT MVFR VSBY
  SHOULD BE LESS FREQUENT THAN VFR.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

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000
FXUS63 KLOT 191935
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
135 PM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 18Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS MIDDAY INTO
EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH
AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL
SUPPORT SOME LIGHT SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE
LIGHT AND NON ACCUMULATING WITH NO SIGNFICIANT VSBY
REDUCTION...BUT THERE COULD BE A BRIEF DUSTING WITH ANY OF THE
HEAVIER SNOW SHOWERS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH IN A PERIOD OF LIGHT AND GENERALLY NON ACCUMULATING SNOW
  SHOWERS THIS AFTERNOON. MEDIUM ON HOW LONG VISIBLITIES WILL BE
  REDUCED TO MVFR AND LOW ON WHETHER CIGS WILL DROP BELOW 2000 FT.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
134 PM CST

A VERY ACTIVE PATTERN CONTINUES FOR LAKE MICHIGAN.  HAVE MADE NO
CHANGES TO THE GOING GALE WARNING OR SMALL CRAFT ADVISORY AS
FORECAST CONDITIONS REMAIN ON TRACK.

A SURFACE TROUGH CROSSING LAKE MICHIGAN TODAY HAD BROUGHT A BRIEF
LULL TO THE WINDS EARLIER TODAY...BUT FOLLOWING THE PASSAGE OF THIS
TROUGH...WINDS HAVE SHIFTED FROM SWLY TO WLY EARLY THIS AFTERNOON
AND ARE RAMPING BACK UP TO PREVAILING WEST GALES.  A SERIES OF MID
LEVEL IMPULSES ROTATING AROUND THE PERIPHERY OF A DEEP UPPER LOW
CENTERED OVER THE HUDSON BAY AREA WILL CONTINUE THE INFLUX OF
UNSEASONABLY COLD AIR INTO THE GREAT LAKES REGION.  THESE IMPULSES
WILL ALLOW SURFACE LOW PRESSURE TO DEEPEN OVER THE UPPER GREAT LAKES
TONIGHT AS HIGH PRESSURE BUILDS ACROSS THE CENTRAL PLAINS.  THE SFC
LOW WILL CONTINUE TO LIFT OUT TO THE NORTHEAST THROUGH ERN QUEBEC
AND INTO NOVA SCOTIA THURSDAY AND THURSDAY NIGHT AS THE HIGH
PRESSURE BUILDS ACROSS THE MIDDLE MISSISSIPPI VALLEY.  THE PRESSURE
GRADIENT OVER THE LAKE WILL GRADUALLY WEAKEN ...BUT WITH THE CENTER
OF THE HIGH SLIDING SOUTH OF THE LAKE...BRISK WEST TO NORTHWEST
WINDS WILL PERSIST THROUGH THURSDAY...THOUGH WITH A WEAKENING
GRADIENT...WINDS SHOULD DROP BELOW GALE FORCE BY LATE THURSDAY
MORNING.  THE RIDGE AXIS SHOULD CROSS THE LAKE THURSDAY NIGHT AND
FRIDAY MORNING...ALLOWING WINDS TO DECREASE FURTHER...AND ANTICIPATE
THAT THE SMALL CRAFT ADVISORY CONDITIONS FOR THE NEARSHORE WATERS
SHOULD STILL COME TO THE END DURING THE DAY ON FRIDAY...AS RESIDUAL
WAVE ACTION SUBSIDES...THOUGH THE ADVISORY CRITERIA WAVES SHOULD
OUTLAST THE ADVISORY CRITERIA WINDS.  THE PERIOD FOR THE POTENTIAL
FOR HAZARDOUS CONDITIONS OVER THE LAKE WILL BE RELATIVELY BRIEF.  AS
THE SFC HIGH MOVES OFF THE SOUTH ATLANTIC COAST OVER THE WEEKEND...A
TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE WESTERN
PLAINS...SETTING UP STRENGTHENING...MORE SOUTHERLY WINDS SATURDAY
NIGHT AND SUNDAY.  BY EARLY NEXT WEEK...THE LONGER RANGE MODELS ARE
INDICATING THAT TWO LOW PRESSURE SYSTEM WILL EVENTUALLY
DEVELOP...ONE OVER THE SOUTHERN CANADIAN PRAIRIES AND ANOTHER OVER
THE RED RIVER VALLEY.  THE FORECAST MODELS ARE SHOWING THAT THE TWO
SYSTEM SHOULD EVENTUALLY MERGE SOMEWHERE OVER THE UPPER MIDWEST AND
DEEPEN OVER THE GREAT LAKES REGION...POSSIBLY BRINGING ANOTHER
PERIOD OVER GALES TO THE LAKE...POSSIBLY AS EARLY AS MONDAY AND THEN
CONTINUING THROUGH THE MIDDLE OF NEXT WEEK.  HOWEVER THERE IS SOME
DISAGREEMENT AMONG THE MODELS AS THE EXACTLY WHERE THE CONSOLIDATED
LOW WILL DEVELOP AND HOW DEEP IT WILL BECOME...SO WILL GO WITH A
RELATIVELY CONSERVATIVE FORECAST FOR NOW...BUT ANTICIPATE THAT THE
FORECAST WINDS IN THE LATTER PORTIONS OF THE PERIOD WILL INCREASE
WITH LATER UPDATES.

KREIN

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 AM THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
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WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KILX 191810
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1210 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes







000
FXUS63 KILX 191810
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1210 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1209 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearing
trend after dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes






000
FXUS63 KILX 191801
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1201 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1201 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearign
trend afetr dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes






000
FXUS63 KILX 191801
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1201 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1201 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearign
trend afetr dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes






000
FXUS63 KILX 191801
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1201 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1201 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearign
trend afetr dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes






000
FXUS63 KILX 191801
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1201 PM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 1201 PM CST WED NOV 19 2014

Cold front has pushed east of the central Illinois terminals late
this morning, resulting in strong W/NW winds across the board.
Based on 12z forecast soundings and the latest upstream
observations, wind gusts will generally remain in the 25 to 30kt
range before gradually subsiding toward sunset. Even though winds
will drop off tonight, pressure gradient will remain tight enough
to support sustained winds of around 10kt through the entire
night. 17z/11am satellite imagery shows low cloud cover spilling
into central Illinois behind the departing front, with the leading
edge currently approaching the I-57 corridor. A narrow band of
MVFR ceilings are noted across the Illinois River Valley, but
these should gradually rise to VFR over the next couple of hours.
Have therefore included MVFR conditions at KPIA/KBMI/KSPI through
20/21z. After that, the big question will be how fast skies clear
tonight. Due to ample upstream cloud cover within the
northwesterly flow pattern, have trended toward the more
pessimistic HRRR solution. End result will be a slow clearign
trend afetr dark, with ceilings scattering out at KSPI by 03z and
further northeast at KCMI by around 06z.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Barnes






000
FXUS63 KLOT 191748
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1148 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 18Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS MIDDAY INTO
EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH
AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL
SUPPORT SOME LIGHT SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE
LIGHT AND NON ACCUMULATING WITH NO SIGNFICIANT VSBY
REDUCTION...BUT THERE COULD BE A BRIEF DUSTING WITH ANY OF THE
HEAVIER SNOW SHOWERS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH IN A PERIOD OF LIGHT AND GENERALLY NON ACCUMULATING SNOW
  SHOWERS THIS AFTERNOON. MEDIUM ON HOW LONG VISIBLITIES WILL BE
  REDUCED TO MVFR AND LOW ON WHETHER CIGS WILL DROP BELOW 2000 FT.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 191748
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1148 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 18Z...

SNOW SHOWERS IN SOUTHWEST WISCONSIN HAVE A HISTORY OF 2-5SM
VISIBILITY FOR A 2-3 HOUR PERIOD AT MOST. THE FORCING ASSOCIATED
WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS MIDDAY INTO
EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT PROGRESSES SOUTH
AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW LEVELS WHICH WILL
SUPPORT SOME LIGHT SNOW SHOWERS. MUCH OF THIS ACTIVITY WILL BE
LIGHT AND NON ACCUMULATING WITH NO SIGNFICIANT VSBY
REDUCTION...BUT THERE COULD BE A BRIEF DUSTING WITH ANY OF THE
HEAVIER SNOW SHOWERS.

CIGS TREND BACK TO VFR TONIGHT WITH SOME CLEARING POSSIBLE. WINDS
REMAIN WESTERLY THROUGH THE PERIOD...STRONGEST THIS
AFTERNOON.

KMD

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* HIGH IN A PERIOD OF LIGHT AND GENERALLY NON ACCUMULATING SNOW
  SHOWERS THIS AFTERNOON. MEDIUM ON HOW LONG VISIBLITIES WILL BE
  REDUCED TO MVFR AND LOW ON WHETHER CIGS WILL DROP BELOW 2000 FT.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH FOR WIND TRENDS.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 191630
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1030 AM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191630
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1030 AM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191630
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1030 AM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191630
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1030 AM CST Wed Nov 19 2014

.UPDATE...
ISSUED AT 1030 AM CST WED NOV 19 2014

16z/10am surface analysis shows cold front quickly pushing toward
the I-57 corridor. Strong southwesterly flow ahead of the boundary
has helped boost temperatures into the middle to upper 30s across
the eastern half of the KILX CWA, while readings remain in the
upper 20s/lower 30s behind the front across the Illinois River
Valley. High temperatures for the day have already been achieved
across the west, but may climb a few more degrees into the lower
40s across the far SE before readings drop back into the 30s this
afternoon after FROPA. Once front passes, northwesterly winds will
increase markedly. Given several ob sites across Iowa showing wind
gusts to between 30 and 35mph, have increased gusts across the
western CWA accordingly. Large area of low clouds and flurries
noted on upstream satellite imagery across Iowa will spill into
central Illinois this afternoon. Latest surface obs show flurries
as close as KCID and a weather observer north of Galesburg noted a
few flurries as well. Have updated sky, temp, and weather grids to
better reflect current and expected trends.

&&

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Barnes
SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KLOT 191607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1007 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 14Z...

MORNING SNOW SHOULD LARGELY REMAIN VFR WITH MODERATE SNOWS
CONFINED TO FAR NORTHEAST ILLINOIS. THERE IS A BAND OF SNOW
SHOWERS BACK IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA THAT HAS A
HISTORY OF 3-5SM VISIBILITY FOR A 2-3 HOUR PERIOD. THE FORCING
ASSOCIATED WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS
MIDDAY INTO EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT
PROGRESSES SOUTH AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW
LEVELS WHICH WILL SUPPORT SOME LIGHT SNOW SHOWERS. HAVE ATTEMPTED
TO TIME THESE IN FOR THE MOST LIKELY PERIOD OF LOWER MVFR
CONDITIONS.  KMD

PREVIOUS DISCUSSION FROM 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* HIGH CONFIDENCE IN A PERIOD OF SNOW SHOWERS WITH MVFR VSBY
  ...MEDIUM-HIGH ON TIMING.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 191607
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1007 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 14Z...

MORNING SNOW SHOULD LARGELY REMAIN VFR WITH MODERATE SNOWS
CONFINED TO FAR NORTHEAST ILLINOIS. THERE IS A BAND OF SNOW
SHOWERS BACK IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA THAT HAS A
HISTORY OF 3-5SM VISIBILITY FOR A 2-3 HOUR PERIOD. THE FORCING
ASSOCIATED WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS
MIDDAY INTO EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT
PROGRESSES SOUTH AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW
LEVELS WHICH WILL SUPPORT SOME LIGHT SNOW SHOWERS. HAVE ATTEMPTED
TO TIME THESE IN FOR THE MOST LIKELY PERIOD OF LOWER MVFR
CONDITIONS.  KMD

PREVIOUS DISCUSSION FROM 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* HIGH CONFIDENCE IN A PERIOD OF SNOW SHOWERS WITH MVFR VSBY
  ...MEDIUM-HIGH ON TIMING.

* HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 191352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
752 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* FLURRIES THIS MORNING.

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 14Z...

MORNING SNOW SHOULD LARGELY REMAIN VFR WITH MODERATE SNOWS
CONFINED TO FAR NORTHEAST ILLINOIS. THERE IS A BAND OF SNOW
SHOWERS BACK IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA THAT HAS A
HISTORY OF 3-5SM VISIBILITY FOR A 2-3 HOUR PERIOD. THE FORCING
ASSOCIATED WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS
MIDDAY INTO EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT
PROGRESSES SOUTH AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW
LEVELS WHICH WILL SUPPORT SOME LIGHT SNOW SHOWERS. HAVE ATTEMPTED
TO TIME THESE IN FOR THE MOST LIKELY PERIOD OF LOWER MVFR
CONDITIONS.  KMD


PREVIOUS DISCUSSION FROM 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* MEDIUM-HIGH CONFIDENCE IN A PERIOD OF SNOW SHOWERS WITH MVFR
  VSBY...MEDIUM ON TIMING.

* MEDIUM-HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 191352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
752 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* FLURRIES THIS MORNING.

* LIGHT SNOW SHOWERS MIDDAY INTO EARLY AFTERNOON WITH MVFR CIGS/VSBY.

* CIGS TRENDING TO MVFR THIS AFTERNOON.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25-28 KT THIS AFTN.

KMD

//DISCUSSION...UPDATED 14Z...

MORNING SNOW SHOULD LARGELY REMAIN VFR WITH MODERATE SNOWS
CONFINED TO FAR NORTHEAST ILLINOIS. THERE IS A BAND OF SNOW
SHOWERS BACK IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA THAT HAS A
HISTORY OF 3-5SM VISIBILITY FOR A 2-3 HOUR PERIOD. THE FORCING
ASSOCIATED WITH THIS ACTIVITY COMES THROUGH NORTHERN ILLINOIS
MIDDAY INTO EARLY AFTERNOON. IT DOES WEAKEN SOMEWHAT AS IT
PROGRESSES SOUTH AND EAST...BUT WE WILL HAVE MORE UNSTABLE LOW
LEVELS WHICH WILL SUPPORT SOME LIGHT SNOW SHOWERS. HAVE ATTEMPTED
TO TIME THESE IN FOR THE MOST LIKELY PERIOD OF LOWER MVFR
CONDITIONS.  KMD


PREVIOUS DISCUSSION FROM 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* MEDIUM-HIGH CONFIDENCE IN A PERIOD OF SNOW SHOWERS WITH MVFR
  VSBY...MEDIUM ON TIMING.

* MEDIUM-HIGH FOR PERIODS OF MVFR CIGS THIS AFTERNOON.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KLOT 191155
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
555 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* FLURRIES INTO EARLY THIS AFTN.

* LIGHT SNOW IS POSSIBLE OVER THE NEXT COUPLE OF HOURS.  CIG AND
  VSBY RESTRICTIONS WILL ONLY BE WITH THE HEAVIER PERIODS OF SNOW.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25 KT THIS AFTN.

JEE

//DISCUSSION...UPDATED 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* LOW CONFIDENCE IN PERIOD OF LIGHT SNOW OCCURRING. HIGH
  CONFIDENCE IN LOWER VSBY AND CIGS WITH HEAVIER SNOW.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO





000
FXUS63 KLOT 191155
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
555 AM CST WED NOV 19 2014

.SHORT TERM...
335 AM CST

TODAY THROUGH FRIDAY...

MAIN FOCUS IN NEAR TERM IS WITH CLIPPER-TYPE SYSTEM MOVING THROUGH
THE REGION THIS MORNING...AND THE POTENTIAL FOR SOME LIGHT
ACCUMULATING SNOW MAINLY ACROSS FAR NORTHERN/NORTHEAST IL. OTHER
HIGHLIGHTS...OR LOW LIGHTS AS THE CASE MAY BE...THROUGH FRIDAY ARE
CONTINUED SUB-NORMAL CHILLY TEMPERATURES AND THE POTENTIAL FOR SOME
LIGHT FREEZING RAIN FRIDAY NIGHT INTO EARLY SATURDAY MORNING AHEAD
OF A SYSTEM WHICH WILL BRING RAIN AND WARMER WEATHER OVER THE
WEEKEND.

EARLY MORNING WATER VAPOR IMAGERY DEPICTS A SHORT-WAVE DIGGING
SOUTHEAST ACROSS THE UPPER MISSISSIPPI VALLEY AND APPROACHING WI/IL
AT 0830Z. SURFACE TROUGH REFLECTION WAS OVER SOUTHERN MN/EAST
CENTRAL IA...WITH FAIRLY IMPRESSIVE SURFACE PRESSURE FALLS SPREADING
INTO SOUTHERN WI/IL AND BACKING WINDS TO THE SOUTH AND RAISING
TEMPS. RADAR RETURNS FROM MID-LEVEL CLOUDS HAVE DEVELOPED SOUTHEAST
FROM TWIN CITIES AREA...THOUGH DRY LOW LEVEL AIR SO FAR HAS SLOWED
DEVELOPMENT OF SNOW AT THE SURFACE. TRACK OF SYSTEM...RADAR TRENDS
AND HIGH-RES HRRR GUIDANCE ALL INDICATE BEST POTENTIAL FOR
MEASURABLE SNOW THROUGH THE EARLY MORNING HOURS WILL BE ALONG A
ROUGHLY MSP-MKE CORRIDOR...WITH GENERALLY LIGHT AMOUNTS OF AN INCH
OR LESS EXPECTED ACROSS FAR NORTHEAST IL AND PARTS OF NORTHERN IN.
FORECAST SOUNDINGS INDICATE DRY AIR ARRIVING IN MID-LEVELS BY
MID-LATE MORNING AND LIMITING BEST FORCING FOR SNOW TO A ONLY A FEW
HOURS THIS AM. SURFACE TROUGH PASSES MID-DAY...WITH RENEWED COLD
ADVECTION AND EXTENSIVE UPSTREAM CLOUDINESS SUPPORTING SCATTERED
FLURRIES THIS AFTERNOON AS LOW-LEVEL THERMAL PROFILES COOL AGAIN.
MOISTURE BECOMES VERY SHALLOW TONIGHT AND THURSDAY...DECREASING
POTENTIAL FOR FLURRIES DESPITE ANOTHER DIGGING SHORT WAVE ACROSS THE
WESTERN LAKES. THE MAIN LARGE-SCALE UPPER TROUGH AXIS THEN SHIFTS
EAST THURSDAY NIGHT...ALLOWING SURFACE HIGH PRESSURE TO SPREAD EAST
ACROSS THE AREA BY FRIDAY MORNING.

TEMPERATURES WERE RISING INTO THE 20S WITH THE SOUTH WINDS THIS
MORNING...WITH HIGHS EXPECTED TO TOP OUT IN THE MID 20S TO LOW 30S
TODAY WITH THE MILDEST TEMPS ACROSS THE FAR EAST/SOUTHEAST CWA.
COLDER TEMPS AGAIN TONIGHT AND THURSDAY...WITH THE COLDEST EXPECTED
EARLY FRIDAY MORNING IN THE VICINITY OF THE SURFACE RIDGE AXIS. LOWS
IN THE SINGLE DIGITS TO LOWER TEENS ARE LIKELY FRIDAY MORNING WITH
LIGHT WINDS AND MOSTLY CLEAR SKIES.

MUCH-TOUTED CHANGE IN THE UPPER PATTERN WILL BE UNDERWAY FRIDAY...
AS FLOW DE-AMPLIFIES AND UPPER TROUGH MOVES ACROSS THE SOUTHWESTERN
STATES AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES FRIDAY NIGHT.
ALONG WITH A DISTURBANCE MOVING ACROSS CENTRAL CANADA...THIS WILL
SET UP SOUTHERLY RETURN FLOW INTO THE REGION FRIDAY NIGHT WITH
ASSOCIATED WARM/MOIST ADVECTION. MODELS CONTINUE TO INDICATE
DEVELOPMENT OF SOME LIGHT PRECIP OVERNIGHT...WITH FORECAST SOUNDINGS
INDICATING ELEVATED WARM LAYER TEMPS APPROACHING +5C WHILE SFC TEMPS
ARE BELOW FREEZING. THIS SUPPORTS THE POTENTIAL FOR SOME LIGHT
FREEZING RAIN OR SLEET FRIDAY NIGHT...BEFORE WARM ADVECTION
EVENTUALLY RAISES SURFACE TEMPS ABOVE FREEZING ON SATURDAY. MODELS
HAVE TRENDED A LITTLE SLOWER WITH ARRIVAL OF LIGHT PRECIP...THOUGH
ALSO SOMEWHAT COLDER INITIALLY AT THE SURFACE. WILL CONTINUE TO
MENTION POTENTIAL FOR FREEZING RAIN/SLEET AND WILL HAVE TO MONITOR
TRENDS FOR THE POTENTIAL OF SOME LIGHT ICE ACCUMULATION LATER FRIDAY
NIGHT INTO EARLY SATURDAY.

RATZER

&&

.LONG TERM...
335 AM CST

SATURDAY THROUGH TUESDAY...

LONGER RANGE MODEL SOLUTIONS CONTINUE TO LIFT SOUTHWESTERN TROUGH
TOWARD THE AREA OVER THE WEEKEND...WITH LOW LEVELS QUICKLY WARMING
ABOVE FREEZING SATURDAY MORNING AND CHANGING ANY MIXED PRECIP OVER
TO RAIN. 00Z GFS/ECMWF HAVE COME INTO BETTER AGREEMENT IN TIMING THE
NEGATIVELY-TILTED SOUTHWESTERN SHORT WAVE AND DEEPENING SURFACE LOW
TO LIFT ACROSS THE FORECAST AREA SUNDAY AFTERNOON/EVENING...WITH
TEMPS RISING INTO THE BALMY 45-50 RANGE. SOME DIFFERENCES REMAIN
WITH THE DETAILS OF PHASING THIS SYSTEM WITH A NORTHERN STREAM
DEVELOPING CLOSED UPPER LOW OVER THE REGION SUNDAY NIGHT INTO
MONDAY...THOUGH REASONABLY SIMILAR IN THE IDEA OF MILD WITH
RAIN/SHOWERS EVENTUALLY GIVING WAY TO LIGHTER RAIN/SNOW TRANSITION
MONDAY-MONDAY NIGHT AND TO LINGERING SNOW SHOWERS TUESDAY AS WE
SHIFT BACK TO A DEEP EASTERN CONUS UPPER TROUGH AND COLDER WEATHER
EARLY NEXT WEEK.

RATZER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* FLURRIES INTO EARLY THIS AFTN.

* LIGHT SNOW IS POSSIBLE OVER THE NEXT COUPLE OF HOURS.  CIG AND
  VSBY RESTRICTIONS WILL ONLY BE WITH THE HEAVIER PERIODS OF SNOW.

* GUSTY WEST WINDS RETURN LATE THIS MORNING WITH PEAK GUSTS ARND
  25 KT THIS AFTN.

JEE

//DISCUSSION...UPDATED 12Z...

RADAR SHOWS DECENT REFLECTIVY ACROSS NORTHERN IL AND NW INDIANA
BUT DRY LOW LEVELS ARE IMPEDING SNOW FROM REACHING THE SURFACE.
AS SUCH BACKED OF SNOW FOR THIS MORNING AND EXPECTING MOSTLY
FLURRIES THROUGH THE EARLY AFTERNOON. MAY SEE A BRIEF HEAVIER SNOW
SHOWER THAT BRINGS DOWN VSBY AND CIGS...BUT NOT OVERLY CONFIDENT.
OUTSIDE OF THE HEAVIER SNOW...CIGS AND VSBY WILL BE VFR. SSE WINDS
BCM WEST BY MID MORNING AND GUST TO ARND 25 KT THIS AFTN. GUSTY
CONDITIONS REMAIN OVERNIGHT WITH GUSTS SLOWLY DIMINISHING OVERNIGHT.

JEE


//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN WINDS AND CIG FCST.

* LOW CONFIDENCE IN PERIOD OF LIGHT SNOW OCCURRING. HIGH
  CONFIDENCE IN LOWER VSBY AND CIGS WITH HEAVIER SNOW.

* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.

JEE

//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...

THURSDAY NIGHT...VFR.

FRIDAY...CHANCE OF A WINTRY MIX OVERNIGHT. IFR LIKELY OVERNIGHT.

SATURDAY...WINTRY MIX BCMG RAIN. IFR LIKELY.

SUNDAY...RAIN AND IFR LIKELY.

MONDAY...CHC -RASN BCMG -SN. MVFR TO IFR CIGS.

TUESDAY...VFR.

JEE

&&

.MARINE...
210 AM CST

HEADLINES...DID NOT MAKE ANY CHANGES TO THE SMALL CRAFT ADVISORY BUT
DID UPGRADE THE OPEN WATER GALE WATCH TO A WARNING. MAY SEE WINDS
DIMINISH TO BELOW GALES FASTER THAN THE WARNING WOULD INDICATE...BUT
HAVE LIMITED CONFIDENCE IN HOW LONG GALES WILL LAST SO LEFT THE END
TIME AS IS.

A TROUGH OF LOW PRESSURE MOVES OVER THE LAKE THIS AFTERNOON WITH
WEST WINDS BECOMING SOUTH OVER THE NEXT FEW HOURS. WINDS RETURN TO
WEST BEHIND THE TROUGH THIS AFTERNOON AND INCREASE TO GALES BY THE
LATE AFTERNOON. GALES CONTINUE OVERNIGHT INTO THURSDAY MORNING...BUT
THEY MAY COME DOWN BELOW GALE FORCE SOONER THAN THE WARNING
INDICATES.  NW WINDS TO 30 KT BECOME WEST 10-20 KT BY FRIDAY
MORNING. HIGH PRESSURE PASSES SOUTH OF THE LAKE LATE THURSDAY NIGHT
AND FRIDAY MORNING WITH LIGHT WINDS BECOMING SOUTH TO SOUTHWEST TO
20 KT BY FRIDAY EVENING. WINDS INCREASE TO 30 KT FRIDAY NIGHT AS THE
GRADIENT TIGHTENS BETWEEN THE DEPARTING HIGH AND A LOW OVER NORTHERN
QUEBEC.  SOUTH WINDS PERSIST THROUGH SATURDAY NIGHT BEFORE BECOMING
SOUTHEAST SUNDAY AHEAD OF THE NEXT LOW. GUIDANCE DIFFERS ON STRONG
THE LOW WILL BE AND ITS EXACT PATH BUT GUIDANCE MEMBERS DO AGREE
THAT THE LAKE WILL MOVE OVER THE LAKE AT SOME POINT SUNDAY NIGHT.

JEE

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
     LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM WEDNESDAY TO 9 AM
     THURSDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 2 PM FRIDAY.

&&

$$

VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO






000
FXUS63 KILX 191121
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
521 AM CST Wed Nov 19 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191121
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
521 AM CST Wed Nov 19 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191121
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
521 AM CST Wed Nov 19 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







000
FXUS63 KILX 191121
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
521 AM CST Wed Nov 19 2014

.SHORT TERM...(Today)
ISSUED AT 349 AM CST WED NOV 19 2014

Very broad 500mb trof dominating the country this morning, with a
small sfc trof/weak front approaching the region.  This morning at
least, with a ridge axis slipping to the southeast, southerly flow
is warming up the temps as the morning goes on...now into the 20s
from the teens earlier tonight.  Short term forecast is rather
benign, though some small chances for snow showers across mainly the
northern portions of the state earlier.  Chance for flurries will
lessen as the day progresses in the wake of the sfc boundary and
have kept the mention only in the north for now, based on satellite
imagery and obs to the NW. Temps will reach very near their max T
early in the NW as the front moves through with more westerly winds
and cooler air by mid day.

&&

.LONG TERM...(Tonight through Tuesday)
ISSUED AT 349 AM CST WED NOV 19 2014

Deep cyclonic flow will keep the temps below normal through the end
of the week, though more southerly winds will begin to set up late
Friday in advance of a developing system to the SW. The main issue
in the forecast is the advancement of the rain while the sfc remains
below zero.  Too dry upstairs to support snow, and threat for fzra
is increasing with the precip preceding the warm up at the sfc after
the sun sets Friday evening.  So much struggle in the last few runs
with timing, and sfc and 850 temps that the detail is still lacking,
and forecast has remained somewhat conservative.  However, growing
concern that the cold air will be slow to erode after 06z early
Saturday has resulted in an extension of the fzra mention
overnight.  So far, little accumulation is showing in the qpf...with
temps struggling near freezing that night in Central Illinois...as
far south as Decatur through midnight...lingering into the early
morning hours. Models still lacking in timing and now the pop spread
is mainly from a messy ECMWF that is lingering precip in the wake of
the exiting system into Tuesday, which was removed from the
forecast.  Best chances for the weekend is in the high chance/likely
category for precip, though the temperature profile for now is still
indicating rain Saturday through Sunday.  With timing issues, am
keeping the likely mention to a minimum with the exception of the
Saturday night/Sunday...which is at least consistent with 24 hrs
ago.  That being said, a gap between the precip with the warm
frontal development and the core of the storm is developing which
may provide a break within that time frame. GFS and ECMWF still
showing some differences...and although the GFS is far more succinct
with the back end of the storm,  has still maintained the double
barrel look to the low center, elongating to the NW. The ECMWF is
becoming increasingly slow and with a lack of kicker wave...cannot
completely buy into either solution.  Either way...the weekend looks
wet, although struggling into the 50s will give Central Illinois a
break from the cold for Sunday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 515 AM CST WED NOV 19 2014

A frontal system will track across the area this morning bringing
gusty southwest winds...which will shift more into a westerly
direction after FROPA (btwn 15z-18z). Not much in the way of
precip associated with the front this morning with the main
weather concern being the stratocumulus clouds tracking southeast
across central Iowa behind the fast moving cold front. Based on
the present movement over Iowa, it appears the low VFR with areas
of MVFR cigs (ranging from 2500-3500 feet) will arrive at PIA and
SPI btwn 14z and 15z and by 17z over at CMI. Forecast soundings
indicate as the colder air moves in, we may see the cloud bases
lower a bit which may take it down to MVFR for a time this
afternoon. Soundings also showing the clouds holding at least
thru 03z before high pressure builds in from the west which should
bring about a gradual clearing trend overnight. South to southwest
winds gusting as high as 23 kts ahead of the front will become
more westerly later this morning into the afternoon hours at 15 to
22 kts with a few gusts up to 30 kts at times before diminishing
this evening from the west.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...HJS
LONG TERM...HJS
AVIATION...Smith







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