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000
FXUS63 KLOT 211144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

//DISCUSSION...UPDATED 12Z...

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. NORTHERLY WINDS WILL
INCREASE TO 10-14KTS IN THE NEXT FEW HOURS AND TURN MORE TO THE
NORTHEAST THIS MORNING AND THIS AFTERNOON. GUSTS INTO THE 16-20KT
RANGE WILL ALSO DEVELOP MID MORNING AND CONTINUE INTO THE
AFTERNOON. WINDS WILL QUICKLY DIMINISH BY EARLY EVENING AND TURN
MORE EAST/NORTHEAST TONIGHT.

LAKE EFFECT RAIN SHOWERS CONTINUE TO MOVE SOUTH INTO NORTHWEST
INDIANA AND WILL AFFECT GYY AT TIMES THIS MORNING. AS THE WINDS
TURN MORE NORTHEAST...THESE SHOWERS MAY MOVE FAR ENOUGH INLAND TO
REACH ORD/MDW. HOWEVER...HAVE MAINTAINED A DRY FORECAST GIVEN THE
EXPECTED SHORT DURATION AND ISOLATED COVERAGE.

4-5KFT VFR CIGS WILL LOWER TO MVFR MID/LATE MORNING...WITH MVFR
CIGS ACROSS EASTERN WI AND SPREADING SOUTH. TIMING AND DURATION
WILL LIKELY NEED TO BE ADJUSTED WITH MORNING UPDATES. CMS

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS. CMS

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

* WEDNESDAY NIGHT...DRY/VFR.
* THURSDAY...CHANCE OF SHRA. SOUTH WINDS.
* FRIDAY AND SATURDAY...DRY/VFR. WEST/SOUTHWEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.
* MONDAY...SLIGHT CHANCE OF SHRA. GUSTY SOUTHWEST WINDS.

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 211144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

//DISCUSSION...UPDATED 12Z...

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. NORTHERLY WINDS WILL
INCREASE TO 10-14KTS IN THE NEXT FEW HOURS AND TURN MORE TO THE
NORTHEAST THIS MORNING AND THIS AFTERNOON. GUSTS INTO THE 16-20KT
RANGE WILL ALSO DEVELOP MID MORNING AND CONTINUE INTO THE
AFTERNOON. WINDS WILL QUICKLY DIMINISH BY EARLY EVENING AND TURN
MORE EAST/NORTHEAST TONIGHT.

LAKE EFFECT RAIN SHOWERS CONTINUE TO MOVE SOUTH INTO NORTHWEST
INDIANA AND WILL AFFECT GYY AT TIMES THIS MORNING. AS THE WINDS
TURN MORE NORTHEAST...THESE SHOWERS MAY MOVE FAR ENOUGH INLAND TO
REACH ORD/MDW. HOWEVER...HAVE MAINTAINED A DRY FORECAST GIVEN THE
EXPECTED SHORT DURATION AND ISOLATED COVERAGE.

4-5KFT VFR CIGS WILL LOWER TO MVFR MID/LATE MORNING...WITH MVFR
CIGS ACROSS EASTERN WI AND SPREADING SOUTH. TIMING AND DURATION
WILL LIKELY NEED TO BE ADJUSTED WITH MORNING UPDATES. CMS

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS. CMS

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

* WEDNESDAY NIGHT...DRY/VFR.
* THURSDAY...CHANCE OF SHRA. SOUTH WINDS.
* FRIDAY AND SATURDAY...DRY/VFR. WEST/SOUTHWEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.
* MONDAY...SLIGHT CHANCE OF SHRA. GUSTY SOUTHWEST WINDS.

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 211144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

//DISCUSSION...UPDATED 12Z...

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. NORTHERLY WINDS WILL
INCREASE TO 10-14KTS IN THE NEXT FEW HOURS AND TURN MORE TO THE
NORTHEAST THIS MORNING AND THIS AFTERNOON. GUSTS INTO THE 16-20KT
RANGE WILL ALSO DEVELOP MID MORNING AND CONTINUE INTO THE
AFTERNOON. WINDS WILL QUICKLY DIMINISH BY EARLY EVENING AND TURN
MORE EAST/NORTHEAST TONIGHT.

LAKE EFFECT RAIN SHOWERS CONTINUE TO MOVE SOUTH INTO NORTHWEST
INDIANA AND WILL AFFECT GYY AT TIMES THIS MORNING. AS THE WINDS
TURN MORE NORTHEAST...THESE SHOWERS MAY MOVE FAR ENOUGH INLAND TO
REACH ORD/MDW. HOWEVER...HAVE MAINTAINED A DRY FORECAST GIVEN THE
EXPECTED SHORT DURATION AND ISOLATED COVERAGE.

4-5KFT VFR CIGS WILL LOWER TO MVFR MID/LATE MORNING...WITH MVFR
CIGS ACROSS EASTERN WI AND SPREADING SOUTH. TIMING AND DURATION
WILL LIKELY NEED TO BE ADJUSTED WITH MORNING UPDATES. CMS

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS. CMS

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

* WEDNESDAY NIGHT...DRY/VFR.
* THURSDAY...CHANCE OF SHRA. SOUTH WINDS.
* FRIDAY AND SATURDAY...DRY/VFR. WEST/SOUTHWEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.
* MONDAY...SLIGHT CHANCE OF SHRA. GUSTY SOUTHWEST WINDS.

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 211144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

//DISCUSSION...UPDATED 12Z...

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. NORTHERLY WINDS WILL
INCREASE TO 10-14KTS IN THE NEXT FEW HOURS AND TURN MORE TO THE
NORTHEAST THIS MORNING AND THIS AFTERNOON. GUSTS INTO THE 16-20KT
RANGE WILL ALSO DEVELOP MID MORNING AND CONTINUE INTO THE
AFTERNOON. WINDS WILL QUICKLY DIMINISH BY EARLY EVENING AND TURN
MORE EAST/NORTHEAST TONIGHT.

LAKE EFFECT RAIN SHOWERS CONTINUE TO MOVE SOUTH INTO NORTHWEST
INDIANA AND WILL AFFECT GYY AT TIMES THIS MORNING. AS THE WINDS
TURN MORE NORTHEAST...THESE SHOWERS MAY MOVE FAR ENOUGH INLAND TO
REACH ORD/MDW. HOWEVER...HAVE MAINTAINED A DRY FORECAST GIVEN THE
EXPECTED SHORT DURATION AND ISOLATED COVERAGE.

4-5KFT VFR CIGS WILL LOWER TO MVFR MID/LATE MORNING...WITH MVFR
CIGS ACROSS EASTERN WI AND SPREADING SOUTH. TIMING AND DURATION
WILL LIKELY NEED TO BE ADJUSTED WITH MORNING UPDATES. CMS

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS. CMS

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

* WEDNESDAY NIGHT...DRY/VFR.
* THURSDAY...CHANCE OF SHRA. SOUTH WINDS.
* FRIDAY AND SATURDAY...DRY/VFR. WEST/SOUTHWEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.
* MONDAY...SLIGHT CHANCE OF SHRA. GUSTY SOUTHWEST WINDS.

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 211144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

//DISCUSSION...UPDATED 12Z...

NO SIGNIFICANT CHANGES TO PREVIOUS FORECAST. NORTHERLY WINDS WILL
INCREASE TO 10-14KTS IN THE NEXT FEW HOURS AND TURN MORE TO THE
NORTHEAST THIS MORNING AND THIS AFTERNOON. GUSTS INTO THE 16-20KT
RANGE WILL ALSO DEVELOP MID MORNING AND CONTINUE INTO THE
AFTERNOON. WINDS WILL QUICKLY DIMINISH BY EARLY EVENING AND TURN
MORE EAST/NORTHEAST TONIGHT.

LAKE EFFECT RAIN SHOWERS CONTINUE TO MOVE SOUTH INTO NORTHWEST
INDIANA AND WILL AFFECT GYY AT TIMES THIS MORNING. AS THE WINDS
TURN MORE NORTHEAST...THESE SHOWERS MAY MOVE FAR ENOUGH INLAND TO
REACH ORD/MDW. HOWEVER...HAVE MAINTAINED A DRY FORECAST GIVEN THE
EXPECTED SHORT DURATION AND ISOLATED COVERAGE.

4-5KFT VFR CIGS WILL LOWER TO MVFR MID/LATE MORNING...WITH MVFR
CIGS ACROSS EASTERN WI AND SPREADING SOUTH. TIMING AND DURATION
WILL LIKELY NEED TO BE ADJUSTED WITH MORNING UPDATES. CMS

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS. CMS

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

* WEDNESDAY NIGHT...DRY/VFR.
* THURSDAY...CHANCE OF SHRA. SOUTH WINDS.
* FRIDAY AND SATURDAY...DRY/VFR. WEST/SOUTHWEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.
* MONDAY...SLIGHT CHANCE OF SHRA. GUSTY SOUTHWEST WINDS.

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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




  [top]

000
FXUS63 KILX 211142
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
642 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.

&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 642 AM CDT TUE OCT 21 2014

Aside from some patchy MVFR fog early this morning and late
tonight, VFR conditions should prevail through the bulk of the 12Z
TAF valid time across the central Illinois terminals. This quiet
weather will be courtesy of a large ridge of high pressure. The
high will also support winds being on the light side, from a
northerly direction today and trending more easterly tonight.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak







000
FXUS63 KILX 211142
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
642 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.

&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 642 AM CDT TUE OCT 21 2014

Aside from some patchy MVFR fog early this morning and late
tonight, VFR conditions should prevail through the bulk of the 12Z
TAF valid time across the central Illinois terminals. This quiet
weather will be courtesy of a large ridge of high pressure. The
high will also support winds being on the light side, from a
northerly direction today and trending more easterly tonight.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak








000
FXUS63 KILX 211142
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
642 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.

&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 642 AM CDT TUE OCT 21 2014

Aside from some patchy MVFR fog early this morning and late
tonight, VFR conditions should prevail through the bulk of the 12Z
TAF valid time across the central Illinois terminals. This quiet
weather will be courtesy of a large ridge of high pressure. The
high will also support winds being on the light side, from a
northerly direction today and trending more easterly tonight.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak







000
FXUS63 KILX 211142
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
642 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.

&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 642 AM CDT TUE OCT 21 2014

Aside from some patchy MVFR fog early this morning and late
tonight, VFR conditions should prevail through the bulk of the 12Z
TAF valid time across the central Illinois terminals. This quiet
weather will be courtesy of a large ridge of high pressure. The
high will also support winds being on the light side, from a
northerly direction today and trending more easterly tonight.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak








000
FXUS63 KLOT 210903
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
403 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210758
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
258 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210758
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
258 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210758
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
258 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210758
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
258 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

258 AM...LOW PRESSURE NEAR LAKE ONTARIO WILL MOVE OFF THE MID
ATLANTIC COAST WEDNESDAY MORNING THEN DEEPEN AGAIN AS IT MOVES
NORTHEAST ALONG THE NEW ENGLAND COAST WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. HIGH PRESSURE OVER ONTARIO WILL STRENGTHEN AS IT
MOVES INTO QUEBEC TONIGHT AND WEDNESDAY...WITH A TRAILING WEAKER
RIDGE BUILDING ACROSS THE WESTERN LAKES TODAY AND CROSSING LAKE
MICHIGAN TONIGHT. NORTH WINDS ARE STILL EXPECTED TO INCREASE TO
30 KT WITH A TIGHT GRADIENT BETWEEN THE APPROACHING RIDGE AND THE
DEPARTING LOW BUT SPEEDS WILL PROBABLY DIMINISH A LITTLE FASTER
THAN PREVIOUSLY INDICATED LATE THIS AFTERNOON INTO THIS EVENING.
THE RIDGE WILL BECOME STATIONARY OVER THE EASTERN LAKES WEDNESDAY
NIGHT AND THURSDAY AS IT WEAKENS. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210740
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
240 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.


&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.


&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Shimon






000
FXUS63 KILX 210740
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
240 AM CDT Tue Oct 21 2014

.SHORT TERM...(Today)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Quiet but cool weather is expected across central and southeast
Illinois today as upper/surface ridging build into the area. Main
forecast concern today revolves around how much cloud cover may
still impact eastern portions of the forecast area which are most
under the influence of the departing mean upper wave/general
cyclonic flow. One more short wave is evident on water vapor imagery
diving due south toward the region from Lake Superior, a feature
that is helping to slow the departure of the cloud shield north and
just east of most of the forecast area. The model consensus suggests
that this wave will not dig too much and that it should not result
in the low clouds spreading across more of the area than they
already are. At this point, only far northeast portion of
forecast area has cloud cover, and this is where it is likely to
remain for much of the day. High temperatures today will be
several degrees cooler than yesterday, but lighter winds and full
sun (in most areas) should still allow for a pleasant fall day.


&&

.LONG TERM...(Tonight through Monday)
ISSUED AT 238 AM CDT TUE OCT 21 2014

Main forecast concern remains with the frontal boundary on Thursday.
A shortwave currently entering northwest Nevada is expected to move
into the Plains states Wednesday afternoon, and across Illinois
Thursday evening. This evening`s model runs have been fairly uniform
in spreading showers further east than before, perhaps as early as
mid morning northwest of the Illinois River. Have introduced 30-40%
PoP`s along and west of I-55 by afternoon. The ECMWF and Canadian
models do bring the precipitation nearly to the Indiana border by
late afternoon, but the forecast soundings in that area remain
rather dry in the lower levels most of the day. Will have to keep an
eye on this though. Have lingered the rain across the northeast
quarter of the forecast area into Thursday evening, but rapid drying
from the top down will quickly diminish the rain as the wave moves
away.

As we get into late week into early next week, the main story will
be with the warm temperatures. Upper level ridging is expected to
build across the central U.S. this weekend, with 850 mb temperatures
progged to rise to around 17C by Sunday evening. This should be
enough to get highs into the lower 70s most areas this weekend and
into Monday.


&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.


&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Shimon







000
FXUS63 KLOT 210718
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
218 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM WEDNESDAY.

&&

$$

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 210718
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
218 AM CDT TUE OCT 21 2014

.DISCUSSION...
218 AM CDT

BELOW AVERAGE TEMPERATURES THE NEXT COUPLE OF DAYS WILL GRADUALLY
GIVE WAY TO A BOUT OF INDIAN SUMMER OVER THE WEEKEND.

WATER VAPOR IMAGERY SHOWS AN AMPLIFYING UPPER TROUGH OVER THE
EASTERN CONUS THIS MORNING WITH LAST EVENING`S UPPER AIR ANALYSIS
SHOWING A POCKET OF SUB-FREEZING 850MB TEMPS ADVECTING SOUTH INTO
THE WESTERN GREAT LAKES REGION. THE CHILLY AIR MOVING OVER THE
RELATIVELY MILDER LAKE WATER IS CURRENTLY RESULTING IN A MARGINAL
LAKE EFFECT SHOWER SET-UP WITH SCATTERED LIGHT SHOWERS OR SPRINKLES
SHOWING UP OVER SOUTHERN LM INTO NW IN. LOW LEVEL FLOW WILL VEER TO
MORE NORTHEASTERLY DIRECTION TODAY AND SEND SOME OF THE LAKE EFFECT
CLOUDINESS AND POTENTIALLY SPRINKLES/LIGHT SHOWERS INTO EXTREME NE
IL THIS MORNING. RELATIVELY LOW INVERSION HEIGHTS AND SOMEWHAT WEAK
INSTABILITY MAKE THE CHANCES OF MEASURABLE PRECIP LOW AND HAVE KEPT
POPS IN THE LOWER END OF THE CHANCE CATEGORY. CLOUDINESS SHOULD BE
MOST PREVALENT TODAY NEAR THE LAKE WITH BETTER INCREASINGLY SUNNY
SKIES WELL INLAND. CLOUD COVER SHOULD KEEP HIGHS STRUGGLING INTO THE
LOWER 50S IN NE IL WHILE MID OR EVEN UPPER 50S ARE POSSIBLE OUT
TOWARD MENDOTA AND FAR SOUTHWESTERN CWA WHERE MORE SUN CAN BE
EXPECTED.

LOW CONFIDENCE IN THE EXTENT OF LAKE CLOUDINESS TONIGHT...WHICH
WOULD PLAY A ROLE IN LOW TEMPS. MORE CLOUDS NEAR THE LAKE WOULD
RESULT IN LOWS A COUPLE DEGREES WARMER THAN CURRENTLY FORECAST AND
VICE VERSA IF MAINLY CLEAR. SUNNY SKIES ARE EXPECTED WEDNESDAY AS
TRANSIENT UPPER RIDGE BUILDS INTO THE AREA BETWEEN DEPARTING DEEP
UPPER TROUGH/LOW AND THE NEXT STRONG NORTHERN STREAM SHORTWAVE
SLATED TO ARRIVE IN OUR AREA LATER THURSDAY. NOT LOOKING FOR MUCH OF
A CHANCE OF SUBSTANTIAL WARMING WEDNESDAY WITH A STILL SOMEWHAT COOL
EASTERLY LOW LEVEL FLOW AND ONLY WEAK LOW LEVEL WARM AIR ADVECTION.

BY THURSDAY SHOWER CHANCES WILL BE ON THE INCREASE AS SHARP NORTHERN
STREAM TROUGH TRACKS SOUTHEAST INTO THE WESTERN LAKES. LACK OF
RETURN FLOW SHOULD RESULT IN LIMITED MOISTURE FOR THE SYSTEM...BUT
FAIRLY STRONG FORCING SHOULD ALLOW FOR A PERIOD OF SHOWERS ACROSS
THE CWA THURSDAY AFTERNOON OR EVENING. NOT MUCH COOLING BEHIND THIS
SYSTEM FRIDAY...THEN A FAST MOVING WEAK CANADIAN COLD FRONT SHOULD
BRING A BRIEF COOL DOWN SATURDAY BEFORE MORE SUBSTANTIAL WARM AIR
ADVECTION SUNDAY INTO MONDAY LIKELY SENDS TEMPERATURES NEAR IF NOT
INTO THE 70S ACROSS THE CWA. MEDIUM RANGE MODELS DO SHOW A
PROGRESSIVE LONG WAVE TROUGH MOVING ACROSS THE CONUS BY EARLY NEXT
WEEK WITH COLD FRONT LIKELY TO ARRIVE LATER MONDAY OR TUESDAY
BRINGING AN END TO OUR BRIEF BUT POTENTIALLY IMPRESSIVE WARM UP.

IZZI

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM WEDNESDAY.

&&

$$

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 210529
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1229 AM CDT TUE OCT 21 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210529
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1229 AM CDT TUE OCT 21 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTH/NORTHEAST WINDS 10-14 KTS AND GUSTY MID MORNING THRU LATE
  AFTERNOON.
* SLIGHT CHANCE FOR SHRA MID MORNING THRU MID AFTERNOON.
* POSSIBLE MVFR CIGS MID MORNING THRU MID AFTERNOON. CMS

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

A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE WESTERN LAKES AND
NORTHERN IL LATE THIS AFTERNOON INTO TONIGHT. NORTHERLY WINDS
AROUND/JUST UNDER 10KTS BEFORE SUNRISE WILL TURN MORE TO THE
NORTHEAST MID/LATE MORNING AND INCREASE IN SPEED TO 10-14KTS WITH
HIGHER GUSTS IN THE UPPER TEEN RANGE LIKELY. SPEEDS/GUSTS SHOULD
QUICKLY DIMINISH BY EARLY EVENING AS THE HIGH CONTINUES BUILDING
SOUTHEAST.

COLDER AIR SPREADING SOUTH WILL AID LAKE EFFECT RAIN SHOWER
DEVELOPMENT EARLY THIS MORNING WHICH WILL AFFECT NORTHWEST INDIANA
AND GYY...BUT AS WINDS TURN NORTHEAST...MAY MOVE WEST TOWARD ORD
AND MDW. CONFIDENCE REGARDING HOW WIDESPREAD THE SHOWERS BECOME IS
FAIRLY LOW...AND THUS JUST NOT CONFIDENT ENOUGH ON COVERAGE TO
INCLUDE AT ORD OR MDW. TRENDS WILL NEED TO BE MONITORED THRU THE
MORNING.

VFR CIGS 4-5KFT EXTEND WELL NORTH INTO WI WITH MVFR OVER THE UPPER
PENINSULA AND FAR NORTHEAST WI. AS THE COLDER AIR ARRIVES...IT
WILL LIKELY PUSH CIGS INTO HIGH MVFR...BUT CONFIDENCE ALSO REMAINS
LOW FOR DURATION OF MVFR CIGS. CMS

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

* HIGH FOR WIND SPEEDS/GUSTS/DIRECTIONS THRU THE PERIOD.
* LOW FOR SHRA MID MORNING THRU MID AFTERNOON.
* MEDIUM FOR MVFR CIGS...LOW FOR TIMING/DURATION. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM WEDNESDAY.

&&

$$

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 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210438
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1138 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1138 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours. The only
clouds of note will be VFR clouds at 6K FT streaming across NE
Illinois. Based on forecast soundings and satellite trends, it
appears those clouds will likely affect our area northeast of a
line from Peoria to Mattoon, including BMI and CMI. A BKN deck
may develop from time to time near BMI/CMI during the first 6-8
hours of the TAF period. Those clouds may linger as long as late
Tuesday afternoon just east of Champaign, but will not affect
aviation flight categories at all.

High pressure advancing into IL behind a cold front has already
produced light and variable winds, with a general direction from
the north. After sunrise tomorrow, wind direction should become
NNE around 8-10kt. After sunset, winds will become easterly and
diminish to 6kt or less.

&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KLOT 210310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR TUESDAY MORNING WITH ISOLATED SHOWERS
  POSSIBLE...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

//DISCUSSION...UPDATED 03Z...

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE NIGHT AND SHOULD BECOME
MVFR TUESDAY MORNING. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED
TO DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING
WHICH WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TUESDAY MORNING
  PERSISTING THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN
  TIMING OF LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM WEDNESDAY.

&&

$$

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 210310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR TUESDAY MORNING WITH ISOLATED SHOWERS
  POSSIBLE...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

//DISCUSSION...UPDATED 03Z...

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE NIGHT AND SHOULD BECOME
MVFR TUESDAY MORNING. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED
TO DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING
WHICH WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TUESDAY MORNING
  PERSISTING THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN
  TIMING OF LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM WEDNESDAY.

&&

$$

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 210310
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1010 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR TUESDAY MORNING WITH ISOLATED SHOWERS
  POSSIBLE...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

//DISCUSSION...UPDATED 03Z...

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE NIGHT AND SHOULD BECOME
MVFR TUESDAY MORNING. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED
TO DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING
WHICH WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TUESDAY MORNING
  PERSISTING THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN
  TIMING OF LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM WEDNESDAY.

&&

$$

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 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210205
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
905 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 900 PM CDT MON OCT 20 2014

A cold front will continue to depart to the southeast of Illinois,
as high pressure begins to build into IL from the west. However, a
broad area of cloud cover upstream in eastern Wisconsin and NE
Illinois will continue to stream to the SE and affect our forecast
area mainly northeast of a line from Peoria to Paris. The
additional cloud cover could keep low temps slightly warmer in the
NE areas. Western areas will have more favorable radiational
cooling conditions under clear skies and light winds in the face
of advancing high pressure. That should allow low temps to dip
toward 40 degrees in a few locations west and north of Lincoln.

Clouds should clear out of eastern areas Tuesday morning, for a
mostly sunny day and highs in the upper 50s to low 60s.

Only minor adjustments were needed to low temps and sky
conditions, so no formal product updates will be needed this evening.

&&

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KILX 210004
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
704 PM CDT Mon Oct 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.

&&

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

$$

SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon







000
FXUS63 KILX 210004
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
704 PM CDT Mon Oct 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.

&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 700 PM CDT MON OCT 20 2014

VFR conditions are expected over the next 24 hours, with mostly
clear skies. There remains some concern about the mass of clouds
in eastern Wisc pushing south-southeast into NE Illinois tonight
and coming close to affecting BMI and CMI. Even if a BKN deck
does develop near BMI/CMI later tonight in that airmass, the
clouds should still be VFR around 4k FT. Those clouds should
depart to the east Tues morning.

Winds will start out NW at 5-9kt this evening, then become
variable as high pressure from MN to KS gradually builds eastward.
After sunrise tomorrow, wind direction should become NNE around
8-10kt.

&&

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

$$

SHORT TERM...HJS
LONG TERM...25
AVIATION...Shimon






000
FXUS63 KLOT 202352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
652 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* VARIABLE NORTH TO NORTHEAST WINDS UNDER 10 KT BECOMING STEADIER
  FROM THE NORTH-NORTHWEST EARLY THIS EVENING.

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR OVERNIGHT WITH ISOLATED SHOWERS POSSIBLE BY
  MORNING...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

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

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE EVENING AND SHOULD BECOME
MVFR TONIGHT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO
DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING WHICH
WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TONIGHT PERSISTING
  THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN TIMING OF
  LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
652 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* VARIABLE NORTH TO NORTHEAST WINDS UNDER 10 KT BECOMING STEADIER
  FROM THE NORTH-NORTHWEST EARLY THIS EVENING.

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR OVERNIGHT WITH ISOLATED SHOWERS POSSIBLE BY
  MORNING...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

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

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE EVENING AND SHOULD BECOME
MVFR TONIGHT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO
DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING WHICH
WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TONIGHT PERSISTING
  THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN TIMING OF
  LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
652 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* VARIABLE NORTH TO NORTHEAST WINDS UNDER 10 KT BECOMING STEADIER
  FROM THE NORTH-NORTHWEST EARLY THIS EVENING.

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR OVERNIGHT WITH ISOLATED SHOWERS POSSIBLE BY
  MORNING...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

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

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE EVENING AND SHOULD BECOME
MVFR TONIGHT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO
DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING WHICH
WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TONIGHT PERSISTING
  THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN TIMING OF
  LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202352
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
652 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* VARIABLE NORTH TO NORTHEAST WINDS UNDER 10 KT BECOMING STEADIER
  FROM THE NORTH-NORTHWEST EARLY THIS EVENING.

* NORTH-NORTHEAST WINDS GREATER THAN 10 KT WITH GUSTS OF 17-20 KT
  TUESDAY.

* CIGS LOWER TO MVFR OVERNIGHT WITH ISOLATED SHOWERS POSSIBLE BY
  MORNING...ESPECIALLY AT MDW.

* MVFR CIGS PERSIST THROUGH MUCH OF THE DAY THEN SCATTER LATE
  AFTERNOON OR EARLY TUESDAY EVENING.

MDB

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

RESIDUAL LAKE INFLUENCE CONTINUES TO PRODUCE NORTHEAST WINDS AT
ORD/MDW/GYY. EXPECT THE LAKE IMPACT TO FADE IN THE NEXT HOUR OR
TWO ALLOWING WINDS TO TURN MORE STEADILY TO THE NORTH/NORTH-
NORTHWEST. CIGS WILL LOWER THROUGH THE EVENING AND SHOULD BECOME
MVFR TONIGHT. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO
DEVELOP OVER LAKE MICHIGAN LATE TONIGHT AND TUESDAY MORNING WHICH
WILL LIKELY IMPACT GYY AT TIMES. THE ILLINOIS SHORELINE WILL
PROBABLY ALSO SEE SOME SPOTTY SHOWERS WHICH MAY REACH ORD/MDW WITH
MDW HAVING THE GREATER POTENTIAL.

STEADY NORTH-NORTHEAST WINDS WILL SET UP TUESDAY MORNING WITH
GUSTS INTO THE 15-20 KT RANGE WHICH WILL EASE OUT TOWARDS RFD IN
THE AFTERNOON...THEN ELSEWHERE WITH SUNSET. MVFR CIGS LOOK TO
PERSIST THROUGH MUCH OF THE DAY WITH THE EXCEPTION BEING RFD WHICH
SHOULD SEE LESS COVERAGE BUT MAY VARY BETWEEN SCT AND BKN. DO NOT
HAVE A GREAT DEAL OF CONFIDENCE IN HOW LONG MVFR PERSISTS INTO THE
AFTERNOON OR EVENING BUT SUSPECT THERE WILL BE AT LEAST SOME
SCATTERING LATER IN THE DAY.

MDB

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

* HIGH CONFIDENCE IN WIND FORECAST THROUGH TUESDAY.

* HIGH CONFIDENCE IN CIGS LOWERING TO MVFR TONIGHT PERSISTING
  THROUGH TUESDAY AFTERNOON BUT LOW CONFIDENCE IN TIMING OF
  LIFTING/SCATTERING TO VFR TUESDAY AFTERNOON/EVENING.

* MEDIUM CONFIDENCE IN SHRA OCCURRING AT MDW AND LOW CONFIDENCE IN
  OCCURRENCE AT ORD.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...

* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

MDB

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202206
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHEAST WINDS AROUND 10 KT BECOMING NORTH LESS THAN 10 KT
  EARLY THIS EVENING. NORTHEAST WINDS 10+KT TUESDAY.

* VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS POSSIBLE LATE TONIGHT/TUESDAY
  MORNING.

MDB

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE BOUNDARY IS WEST OF ORD/MDW AND SOUTH OF GYY. WINDS
AT THESE TERMINALS WILL CONTINUE TO BE NORTHEASTERLY RIGHT AROUND
10 KT WITH GUSTS LIKELY TO HAVE ENDED. EXPECT A GRADUAL TREND BACK
TO A 360-010 WIND OVER THE NEXT 1-2 HRS WITH SPEEDS CONSISTENTLY
UNDER 10 KT BY 01Z IF NOT 00Z.

MDB

FROM 18Z...

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* HIGH CONFIDENCE IN WIND TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE IN SHOWERS IMPACTING THE TERMINALS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202206
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHEAST WINDS AROUND 10 KT BECOMING NORTH LESS THAN 10 KT
  EARLY THIS EVENING. NORTHEAST WINDS 10+KT TUESDAY.

* VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS POSSIBLE LATE TONIGHT/TUESDAY
  MORNING.

MDB

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE BOUNDARY IS WEST OF ORD/MDW AND SOUTH OF GYY. WINDS
AT THESE TERMINALS WILL CONTINUE TO BE NORTHEASTERLY RIGHT AROUND
10 KT WITH GUSTS LIKELY TO HAVE ENDED. EXPECT A GRADUAL TREND BACK
TO A 360-010 WIND OVER THE NEXT 1-2 HRS WITH SPEEDS CONSISTENTLY
UNDER 10 KT BY 01Z IF NOT 00Z.

MDB

FROM 18Z...

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* HIGH CONFIDENCE IN WIND TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE IN SHOWERS IMPACTING THE TERMINALS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202206
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHEAST WINDS AROUND 10 KT BECOMING NORTH LESS THAN 10 KT
  EARLY THIS EVENING. NORTHEAST WINDS 10+KT TUESDAY.

* VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS POSSIBLE LATE TONIGHT/TUESDAY
  MORNING.

MDB

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE BOUNDARY IS WEST OF ORD/MDW AND SOUTH OF GYY. WINDS
AT THESE TERMINALS WILL CONTINUE TO BE NORTHEASTERLY RIGHT AROUND
10 KT WITH GUSTS LIKELY TO HAVE ENDED. EXPECT A GRADUAL TREND BACK
TO A 360-010 WIND OVER THE NEXT 1-2 HRS WITH SPEEDS CONSISTENTLY
UNDER 10 KT BY 01Z IF NOT 00Z.

MDB

FROM 18Z...

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* HIGH CONFIDENCE IN WIND TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE IN SHOWERS IMPACTING THE TERMINALS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202206
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHEAST WINDS AROUND 10 KT BECOMING NORTH LESS THAN 10 KT
  EARLY THIS EVENING. NORTHEAST WINDS 10+KT TUESDAY.

* VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS POSSIBLE LATE TONIGHT/TUESDAY
  MORNING.

MDB

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE BOUNDARY IS WEST OF ORD/MDW AND SOUTH OF GYY. WINDS
AT THESE TERMINALS WILL CONTINUE TO BE NORTHEASTERLY RIGHT AROUND
10 KT WITH GUSTS LIKELY TO HAVE ENDED. EXPECT A GRADUAL TREND BACK
TO A 360-010 WIND OVER THE NEXT 1-2 HRS WITH SPEEDS CONSISTENTLY
UNDER 10 KT BY 01Z IF NOT 00Z.

MDB

FROM 18Z...

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* HIGH CONFIDENCE IN WIND TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE IN SHOWERS IMPACTING THE TERMINALS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202206
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
505 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACK EDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHEAST WINDS AROUND 10 KT BECOMING NORTH LESS THAN 10 KT
  EARLY THIS EVENING. NORTHEAST WINDS 10+KT TUESDAY.

* VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS POSSIBLE LATE TONIGHT/TUESDAY
  MORNING.

MDB

//DISCUSSION...UPDATED 22Z...

LAKE BREEZE BOUNDARY IS WEST OF ORD/MDW AND SOUTH OF GYY. WINDS
AT THESE TERMINALS WILL CONTINUE TO BE NORTHEASTERLY RIGHT AROUND
10 KT WITH GUSTS LIKELY TO HAVE ENDED. EXPECT A GRADUAL TREND BACK
TO A 360-010 WIND OVER THE NEXT 1-2 HRS WITH SPEEDS CONSISTENTLY
UNDER 10 KT BY 01Z IF NOT 00Z.

MDB

FROM 18Z...

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* HIGH CONFIDENCE IN WIND TRENDS.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE IN SHOWERS IMPACTING THE TERMINALS.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202001
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
301 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON WITH VARYING LAKE BREEZE...THEN BECOMING NORTHEAST
  WITH SPEEDS AT OR ABOVE 10 KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202001
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
301 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON WITH VARYING LAKE BREEZE...THEN BECOMING NORTHEAST
  WITH SPEEDS AT OR ABOVE 10 KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202001
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
301 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON WITH VARYING LAKE BREEZE...THEN BECOMING NORTHEAST
  WITH SPEEDS AT OR ABOVE 10 KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 202001
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
301 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.

BEACHLER

&&

.AVIATION...

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

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON WITH VARYING LAKE BREEZE...THEN BECOMING NORTHEAST
  WITH SPEEDS AT OR ABOVE 10 KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

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

* MEDIUM CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.


BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT MON OCT 20 2014

.DISCUSSION...
249 PM CDT

TONIGHT...
UPPER LEVEL WAVE CONTINUES TO ROTATE OVER NORTHEAST ONTARIO...WITH A
A COUPLE WEAK LOBES OF VORTICITY ROTATING AROUND THE BACKEDGE OF
THIS SYSTEM...PUSHING SOUTH INTO THE NORTHERN GREAT LAKES. VISIBLE
IMAGERY SHOWS CONSIDERABLE CLOUD COVER ACROSS MICHIGAN...STRETCHING
WEST ACROSS THE LAKE AND BEGINNING TO SLIDE INTO FAR NORTHEAST IL.
GUIDANCE SUGGESTS A FEW LIGHT SHOWERS WILL ACCOMPANY THIS WAVE AS IT
PUSHES SOUTHEAST ACROSS WISCONSIN AND PERHAPS INTO FAR NORTHEAST IL
LATE THIS EVE...BEFORE SHIFTING EAST INTO FAR NORTHWEST IN BY
DAYBREAK TUE. OTHERWISE EXPECT CLOUDS TO THICKEN THIS EVE ACROSS THE
CWFA...PERHAPS LESS CLOUD COVER ACROSS THE FAR WEST/SOUTHWEST
PORTIONS OF THE FORECAST AREA. WITH THE CLOUD COVER TONIGHT...THIS
SHOULD KEEP TEMPS GENERALLY AROUND 40 TO THE LOW 40S TONIGHT.

TUESDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL BEGIN TO PUSH EAST...WITH A HIGH AMPLITUDE
RIDGE BEGINNING TO BUILD INTO THE REGION FROM THE CENTRAL PLAINS.
THIS WILL BRING A BROAD SFC RIDGE TO THE AREA STRETCHING FROM
CENTRAL CANADA SOUTH TO THE WESTERN GULF. GUIDANCE THEN CONTINUES TO
MAINTAIN THIS FEATURE THROUGH THUR MORNING...HOWEVER THERE IS A WEAK
WAVE SLIDING EAST ACROSS THE CENTRAL CONUS WED NGT THAT IS PROGGED
TO LIFT NORTHEAST OF THE CWFA THUR AFTN/EVE. THIS SYSTEM COULD BRING
SOME LIGHT PRECIP TO THE AREA...BUT AT THIS TIME HAVE ONLY GONE WITH
SLIGHT CHANCE OF POPS GIVEN THE MOISTURE AVAILABILITY APPEARS TO BE
MINIMAL. TEMPS WILL GENERALLY BE IN THE UPR 50S TO LOW 60S...WITH
OVERNIGHT LOWS IN THE MID 30S TO MID 40S.

FRIDAY THROUGH MONDAY...
ENSEMBLES CONTINUE TO FEATURE A TROUGH PERSISTING ALONG THE FAR
SOUTHWEST CONUS...ALLOWING RIDGING TO DOMINATE THE CENTRAL CONUS
LATE IN THE WEEK INTO THE WEEKEND. THIS WILL LIKELY CONTINUE THE DRY
PATTERN FOR THE REGION. IN ADDITION IT APPEARS TEMPS WILL BE ABLE TO
STEADILY MODERATE...PERHAPS REACHING THE UPR 60S TO ARND 70.

ENSEMBLES DO SUGGEST THAT TOWARDS THE SECOND HALF OF THE WEEKEND THE
RIDGE WILL BEGIN TO DRIFT EAST...WITH A TROUGH DIGGING INTO THE
CENTRAL CONUS AND PERHAPS BRINGING UNSETTLED WEATHER BACK INTO THE
REGION EARLY NEXT WEEK.


BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

250 PM...LOW PRESSURE CONTINUES TO INFLUENCE THE REGION CENTERED
OVER NORTHERN LAKE HURON LATE THIS AFTERNOON AND IS EXPECTED TO
SLOWLY DRIFT EAST OVERNIGHT. THIS LOW WILL THEN REACH LAKE ONTARIO
AROUND DAYBREAK TUE. THE BACK EDGE OF THIS LOW CONTINUES TO
FEATURE A TIGHTENING PRESSURE GRADIENT...WHICH HAS PRODUCED GUSTY
WINDS JUST BEGINNING TO SLIDE OVER THE NORTHERN PORTIONS OF THE
LAKE. THESE GUSTY WINDS WILL EVENTUALLY SLIDE SOUTH THIS
EVENING...AND EXPECT NORTH GUSTS UP TO 30 KTS. HIGH PRESSURE OVER
ONTARIO WILL BEGIN TO BUILD SOUTH OVERNIGHT...THEN STRETCH FROM
ONTARIO SOUTH TO THE WESTERN GULF OF MEXICO BY TUE NGT. THIS WILL
BRING MUCH LIGHTER WINDS TO THE LAKE BY WED.

BEACHLER

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201942
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
242 PM CDT Mon Oct 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.


&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.


&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1237 PM CDT MON OCT 20 2014

Northwesterly flow today with clear skies becoming more northerly
by morning. Light and somewhat variable in the overnight. Some
moisture in the low levels may develop into some sct clouds...with
more bkn deck to the north and northeast. Some concern that the
shortwave over the upper Midwest would dive into the region and
threaten ILX terminals with a more bkn deck. NAM is the only one
showing enough moisture to cover CMI and BMI...other models drier,
including the HRRR. For now, will maintain the SCT mention, though
later issuances may require a bkn deck for CMI and BMI.


&&

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

$$

SHORT TERM...HJS
LONG TERM...25
AVIATION...HJS






000
FXUS63 KILX 201942
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
242 PM CDT Mon Oct 20 2014

.SHORT TERM...(Tonight)
ISSUED AT 242 PM CDT MON OCT 20 2014

Weak low pressure over the Great Lakes this afternoon with a weak
boundary trailing out behind it through Central and Southeastern
Illinois.  Forecast for the overnight rather quiet with
northwesterly flow continuing, though the winds may be variable at
times, becoming light after sunset.  Dry air filtering into the CWA
as the overnight cools should keep the RH just sub saturation.  This
in concert with winds at or above 5kt or so...fog issues are not
expected.  However, another wave making its way into the larger
scale trof from nrn MN is keeping a lobe of lower clouds a bit
further out to the west.  This particular area is expected to dive
southeast in the overnight hours...while the rest of the system
pulls out to the east on the synoptic scale.  The NAM is keeping the
llvls far more significant and brushing ILX northeast with the edge
of the more substantial cloud cover.  Remaining models not really
holding onto as much.  Sat imagery also shows a slow erosion of the
western edge of the clouds...as well as the HRRR supporting the
clouds staying to the north and northeast.  It may be close, but
leaving the overnight mostly clear and lows dipping into the low to
mid 40s.


&&

.LONG TERM...(Tuesday through Monday)
ISSUED AT 242 PM CDT MON OCT 20 2014

As the 500 mb wave cuts off over the eastern Great Lakes tomorrow,
the northeast CWA will be on the southwest fringe of better
moist/cyclonic flow, and will be close to strato-cu deck.  Most
high-res models keep thicker cloud cover to our east and will
continue to trend forecast that way.  Regardless, highs will be
several degrees below normal, ranging from the mid 50s northeast to
low 60 in the south/southwest.

Wednesday and Thursday...Surface and and upper level ridging shift across
the Midwest ahead of the next upper level weakness moving into the
northern Plains.  This will provide clear/dry and seasonably cool
weather.  As the next system shifts into the upper Midwest, showers
should overspread Iowa and Missouri early Thursday.  However as the
dynamics with this feature shift east of the Mississippi River it
will encounter increasingly dry air and surface/upper ridging.  As a
result most of the shower activity is expected to decay during the
afternoon/evening as it shifts through the northern half of the
CWA.  Slight chance pops will cover this possibility.

Friday through Monday...Medium range guidance/ensembles show good
agreement that a pronounced warming trend will affect the region.
This will result from troughs affecting the west and east coasts,
allowing upper ridging to build across the central U.S., and drawing
up a thermal ridge from the southern Plains, pushing 850 mb temps to
+12-16 C this weekend.  Friday will see some moderation with
readings returning near to slightly above normal.  In a rarity for
early fall, highs on Saturday and Sunday are progged to be 10-15
degrees above normal without strong winds aiding in low level warm
advection, due to high pressure in the vicinity.  If the GFS is
correct, southerly flow will increase later Sunday in tightening
gradient ahead of the next low pressure complex in the Plains.  As
this system shifts east it will bring the next chance of rain to the
region for early next week. Considerable uncertainty exists at
that range, with the 12z ECMWF depicting a much weaker system.


&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1237 PM CDT MON OCT 20 2014

Northwesterly flow today with clear skies becoming more northerly
by morning. Light and somewhat variable in the overnight. Some
moisture in the low levels may develop into some sct clouds...with
more bkn deck to the north and northeast. Some concern that the
shortwave over the upper Midwest would dive into the region and
threaten ILX terminals with a more bkn deck. NAM is the only one
showing enough moisture to cover CMI and BMI...other models drier,
including the HRRR. For now, will maintain the SCT mention, though
later issuances may require a bkn deck for CMI and BMI.


&&

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

$$

SHORT TERM...HJS
LONG TERM...25
AVIATION...HJS







000
FXUS63 KLOT 201813
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
113 PM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201813
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
113 PM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201813
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
113 PM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201813
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
113 PM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* NORTHWEST WINDS/GUSTS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...THEN BECOMING NORTHEAST WITH SPEEDS AT OR ABOVE 10
  KT TUESDAY MORNING.

* DEVELOPING VFR CEILINGS BECOMING MVFR EARLY TUESDAY MORNING.

* PERIODIC/ISOLATED LIGHT SHOWERS.

RODRIGUEZ

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

MOSTLY CLEAR SKIES STILL PRESENT ACROSS THE TERMINALS EARLY THIS
AFTERNOON...WHILE NORTHWEST WINDS CONTINUE TO SLOWLY INCREASE.
DEVELOPING DIURNAL STRATOCU WILL SPREAD OVER THE AREA OVER THE
NEXT 1-2 HOURS AND ALTHOUGH THERE MAY BE A BRIEF PERIOD OF HIGH
END MVFR CEILINGS...DO THINK THAT VFR CEILINGS WILL PREVAIL THIS
AFTERNOON. NORTHWEST WINDS/GUSTS WILL STEADILY INCREASE OVER THE
NEXT COUPLE OF HOURS WITH A POSSIBILITY REMAINING FOR WINDS TO
BRIEFLY GO MORE NORTHERLY. THIS SHOULD ALSO BE BRIEF WITH A
NORTHWEST WIND LIKELY FAVORED. WITH VFR CEILINGS REMAINING
OVERHEAD TONIGHT...THE NORTHWEST WINDS WILL DIMINISH BEFORE
QUICKLY INCREASING ABOVE 10 KT OUT OF THE NORTHEAST EARLY TUESDAY
MORNING. AS THIS OCCURS...ANTICIPATE ALREADY PRESENT MVFR CEILINGS
OVER THE LAKE TO MOVE WEST ACROSS THE TERMINALS...EXCEPT RFD.
THERE WILL ALSO BE A PERIOD OF SCATTERED LIGHT SHOWERS TO SPILL
OFF THE LAKE DURING THIS TIME...BUT WITH MDW/GYY THE LIKELY
LOCATIONS TO OBSERVE THIS PRECIP.

RODRIGUEZ


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.

* HIGH CONFIDENCE WITH VFR CEILINGS...MEDIUM CONFIDENCE WITH MVFR
  CEILINGS.

* MEDIUM CONFIDENCE WITH LIGHT SHOWERS.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201740
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1240 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 1029 AM CDT MON OCT 20 2014
Weak low pressure over the Great Lakes with the trof axis/weak boundary reaching
back across ILX this morning. Very narrow line of showers
developing with some assist from the low level jet this morning
over east central Illinois along the Indiana border. Northwesterly
flow dominating the state today with plenty of sunshine warming
temps up to near climate normals. Some minor tweaks to sct cloud
cover through the afternoon... but no large scale changes to the
forecast anticipated at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1237 PM CDT MON OCT 20 2014

Northwesterly flow today with clear skies becoming more northerly
by morning. Light and somewhat variable in the overnight. Some
moisture in the low levels may develop into some sct clouds...with
more bkn deck to the north and northeast. Some concern that the
shortwave over the upper Midwest would dive into the region and
threaten ILX terminals with a more bkn deck. NAM is the only one
showing enough moisture to cover CMI and BMI...other models drier,
including the HRRR. For now, will maintain the SCT mention, though
later issuances may require a bkn deck for CMI and BMI.

&&

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

$$

UPDATE...HJS
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...HJS






000
FXUS63 KILX 201740
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1240 PM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 1029 AM CDT MON OCT 20 2014
Weak low pressure over the Great Lakes with the trof axis/weak boundary reaching
back across ILX this morning. Very narrow line of showers
developing with some assist from the low level jet this morning
over east central Illinois along the Indiana border. Northwesterly
flow dominating the state today with plenty of sunshine warming
temps up to near climate normals. Some minor tweaks to sct cloud
cover through the afternoon... but no large scale changes to the
forecast anticipated at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1237 PM CDT MON OCT 20 2014

Northwesterly flow today with clear skies becoming more northerly
by morning. Light and somewhat variable in the overnight. Some
moisture in the low levels may develop into some sct clouds...with
more bkn deck to the north and northeast. Some concern that the
shortwave over the upper Midwest would dive into the region and
threaten ILX terminals with a more bkn deck. NAM is the only one
showing enough moisture to cover CMI and BMI...other models drier,
including the HRRR. For now, will maintain the SCT mention, though
later issuances may require a bkn deck for CMI and BMI.

&&

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

$$

UPDATE...HJS
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...HJS







000
FXUS63 KLOT 201622
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1122 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* NORTHWEST WINDS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...WITH GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201622
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1122 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* NORTHWEST WINDS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...WITH GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201622
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1122 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* NORTHWEST WINDS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...WITH GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201622
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1122 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* NORTHWEST WINDS BRIEFLY BECOMING MORE NORTHERLY THIS
  AFTERNOON...WITH GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 16Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201536
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1036 AM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 1029 AM CDT MON OCT 20 2014
Weak low pressure over the Great Lakes with the trof axis/weak boundary reaching
back across ILX this morning. Very narrow line of showers
developing with some assist from the low level jet this morning
over east central Illinois along the Indiana border. Northwesterly
flow dominating the state today with plenty of sunshine warming
temps up to near climate normals. Some minor tweaks to sct cloud
cover through the afternoon... but no large scale changes to the
forecast anticipated at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 656 AM CDT MON OCT 20 2014

VFR conditions expected to prevail through the 12Z TAF valid time
across the central Illinois terminals. A cold front will swing
through the area this morning, with winds shifting from southwest
to northwest. Minimal cloud cover is expected overall, but will
need to keep an eye on clouds dropping south out of the upper
Great Lakes and central Canada. Most guidance has these low clouds
staying north/east of the terminals, but it will likely be a close
call, especially at KCMI.


&&

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

$$

UPDATE...HJS
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak






000
FXUS63 KILX 201536
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1036 AM CDT Mon Oct 20 2014

.UPDATE...
ISSUED AT 1029 AM CDT MON OCT 20 2014
Weak low pressure over the Great Lakes with the trof axis/weak boundary reaching
back across ILX this morning. Very narrow line of showers
developing with some assist from the low level jet this morning
over east central Illinois along the Indiana border. Northwesterly
flow dominating the state today with plenty of sunshine warming
temps up to near climate normals. Some minor tweaks to sct cloud
cover through the afternoon... but no large scale changes to the
forecast anticipated at this time.

&&

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 656 AM CDT MON OCT 20 2014

VFR conditions expected to prevail through the 12Z TAF valid time
across the central Illinois terminals. A cold front will swing
through the area this morning, with winds shifting from southwest
to northwest. Minimal cloud cover is expected overall, but will
need to keep an eye on clouds dropping south out of the upper
Great Lakes and central Canada. Most guidance has these low clouds
staying north/east of the terminals, but it will likely be a close
call, especially at KCMI.


&&

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

$$

UPDATE...HJS
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak







000
FXUS63 KLOT 201415
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
915 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* WESTERLY WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON AND THEN NORTH/NORTHEAST LATE THIS AFTERNOON...WITH
  GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201415
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
915 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* WESTERLY WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON AND THEN NORTH/NORTHEAST LATE THIS AFTERNOON...WITH
  GUSTS DEVELOPING BY MIDDAY.

* POSSIBLE MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 14Z...

* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION THROUGH EARLY
  AFTERNOON...THEN MEDIUM CONFIDENCE WITH DIRECTION LATER THIS
  AFTERNOON.

* MEDIUM CONFIDENCE WITH MVFR CIGS TODAY AND EVENING.

RODRIGUEZ

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201201
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
701 AM CDT Mon Oct 20 2014

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 656 AM CDT MON OCT 20 2014

VFR conditions expected to prevail through the 12Z TAF valid time
across the central Illinois terminals. A cold front will swing
through the area this morning, with winds shifting from southwest
to northwest. Minimal cloud cover is expected overall, but will
need to keep an eye on clouds dropping south out of the upper
Great Lakes and central Canada. Most guidance has these low clouds
staying north/east of the terminals, but it will likely be a close
call, especially at KCMI.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak







000
FXUS63 KILX 201201
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
701 AM CDT Mon Oct 20 2014

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.

&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
ISSUED AT 656 AM CDT MON OCT 20 2014

VFR conditions expected to prevail through the 12Z TAF valid time
across the central Illinois terminals. A cold front will swing
through the area this morning, with winds shifting from southwest
to northwest. Minimal cloud cover is expected overall, but will
need to keep an eye on clouds dropping south out of the upper
Great Lakes and central Canada. Most guidance has these low clouds
staying north/east of the terminals, but it will likely be a close
call, especially at KCMI.

&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak






000
FXUS63 KLOT 201144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* WEST/SOUTHWEST WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON...THEN NORTH/NORTHEAST LATE THIS AFTERNOON.
* POSSIBLE MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING.
* LOW FOR MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* WEST/SOUTHWEST WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON...THEN NORTH/NORTHEAST LATE THIS AFTERNOON.
* POSSIBLE MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING.
* LOW FOR MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* WEST/SOUTHWEST WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON...THEN NORTH/NORTHEAST LATE THIS AFTERNOON.
* POSSIBLE MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING.
* LOW FOR MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201144
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
644 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

//PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 12Z...

* WEST/SOUTHWEST WINDS BECOMING NORTHWEST LATE MORNING/EARLY THIS
  AFTERNOON...THEN NORTH/NORTHEAST LATE THIS AFTERNOON.
* POSSIBLE MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//DISCUSSION...UPDATED 12Z...

LINE OF SHRA/TSRA DEVELOPED OVER FAR NORTHEAST IL IN THE PAST HOUR
OR SO AHEAD OF AN UPPER LEVEL WAVE. THIS ACTIVITY WILL CONTINUE TO
MOVE EAST...AFFECTING GYY SHORTLY. THE SURFACE COLD FRONT WILL
MOVE ACROSS THE TERMINALS THIS MORNING SHIFTING WEST/SOUTHWEST
WINDS TO THE NORTHWEST. WINDS WILL CONTINUE TO SLOWLY TURN MORE
NORTH/NORTHWEST BY MID/LATE AFTERNOON. THE GRADIENT IS THEN
EXPECTED TO WEAKEN ENOUGH FOR WIND DIRECTIONS TO SHIFT TO THE
NORTH/NORTHEAST EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING
WITH PREVAILING SPEEDS AT THAT TIME LIKELY UNDER 10KTS. WINDS WILL
TURN BACK TO THE NORTH/NORTHWEST OVERNIGHT.

LOW VFR/HIGH MVFR CIGS ACROSS NORTHERN WI WILL MOVE SOUTH THIS
MORNING REACHING THE TERMINALS LATE THIS MORNING OR EARLY THIS
AFTERNOON. CONFIDENCE REGARDING SPECIFIC CIG HEIGHTS IS FAIRLY LOW
WITH CIGS POSSIBLE DIPPING INTO HIGH MVFR FROM MID AFTERNOON INTO
THE EVENING HOURS.

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING.
* LOW FOR MVFR CIGS THIS AFTERNOON AND EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...

* TUESDAY NIGHT...DRY/VFR.
* WEDNESDAY...DRY/VFR. EAST/NORTHEAST WINDS.
* THURSDAY...DRY/VFR. SOUTH WINDS.
* FRIDAY...DRY/VFR. SOUTHWEST WINDS.
* SATURDAY...DRY/VFR. WEST WINDS.
* SUNDAY...DRY/VFR. SOUTH WINDS.

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201058 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
558 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

&&

.PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201058 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
558 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

&&

.PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201058 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
558 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

&&

.PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 201058 AAA
AFDLOT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
558 AM CDT MON OCT 20 2014

.DISCUSSION...
557 AM CDT

WE ARE SEEING SCATTERED SHOWERS SPARK NEAR CHICAGO AS OF 555 AM
AHEAD OF THE UPPER DISTURBANCE MENTIONED IN THE PREVIOUS
DISCUSSION. THIS DISTURBANCE HAS A POCKET OF STEEP LAPSE RATES
ALOFT /500MB-750MB/ OF 8C/KM AND GREATER AND THAT IS AIDING SOME
OF THESE SHOWER UPDRAFTS. THIS IS INDICATED BY A COUPLE LIGHTNING
STRIKES OVER LAKE MI AND THE OBSERVERS AT ORD AND MDW REPORTING
INTRA-CLOUD AND CLOUD-TO-AIR LIGHTNING. THE GOOD NEWS IS THIS
UPPER WAVE AND ITS FORCING IS MOVING ABOUT 35-40 MPH SO NOT
EXPECTING THESE TO STICK AROUND THE CHICAGO AREA AFTER 7 AM.
CONTINUE THE SHOWER CHANCES THIS MORNING AS IS IN NORTHWEST
INDIANA AND HAVE ADDED A SLIGHT CHANCE OF THUNDER FOR AREAS NEAR
THE I-80/I-90 CORRIDOR.

MTF

&&

.PREV DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200909
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
409 AM CDT MON OCT 20 2014

.DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200909
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
409 AM CDT MON OCT 20 2014

.DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOMING WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

* HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
  TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200819
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
319 AM CDT MON OCT 20 2014

.DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200819
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
319 AM CDT MON OCT 20 2014

.DISCUSSION...
319 AM CDT

A QUIET WEATHER PATTERN WILL REMAIN IN PLACE IN TERMS OF LACK OF
PRECIPITATION CHANCES AND ANY HIGH IMPACT WEATHER THROUGH NEXT
WEEKEND...THOUGH STILL SEVERAL LITTLE INTERESTS TO TACKLE. THESE
INCLUDED HOW WIDESPREAD CLOUDS WILL REACH LATER TODAY THROUGH
TUESDAY AS WELL AS LAKE EFFECT SHOWER POTENTIAL DURING THAT TIME.
THEN LOOKING AT WHEN AND HOW QUICKLY OF A WARM-UP OCCURS LATE IN
THE WEEK INTO THE WEEKEND.

TODAY THROUGH TUESDAY...
THE CONTINUED AMPLIFIED BUT PROGRESSIVE FLOW OVER CANADA AND THE
NORTHERN CONUS CONTINUES FOR A LITTLE LONGER WITH A PACIFIC/CLIPPER
HYBRID SYSTEM MOVING SOUTHEASTWARD FROM THE CENTRAL GREAT LAKES.
AROUND THIS A WELL-DEFINED SHORT WAVE ON GOES WATER VAPOR IMAGERY IS
MOVING INTO NORTHERN IL EARLY THIS MORNING. THIS IS FAIRLY MOISTURE
STARVED BUT CANNOT RULE OUT A FEW SHOWERS THIS MORNING MAINLY IN
NORTHWEST INDIANA. THIS SHORT WAVE ALSO BEGINS TO BREAK DOWN THE
LOW-LEVEL THERMAL RIDGE OVER THE AREA...WITH CLOUDS LIKELY TO
ADVECT/DEVELOP SOUTHWARD INTO THE FORECAST AREA THIS AFTERNOON. IN
ADDITION...TEMPERATURES MAY ALSO PEAK EARLY IN THE AFTERNOON AND
THEN EXPERIENCE A SLOW DROP. TEMPERATURES SHOULD STILL PEAK AROUND
CLIMATOLOGICAL NORMAL /60 TO 65/ WITH THE MORNING SUN. THE CYCLONIC
FLOW OVER THE REGION AND RAPIDLY COOLING 850-925MB TEMPERATURES LOOK
TO SUPPORT CLOUDS OVER MUCH OF THE AREA BY EARLY THIS EVENING AND
UPSTREAM OBSERVATIONAL TRENDS SUPPORT THIS. HAVE GONE WELL ABOVE
MOST GUIDANCE IN SKY COVER FROM LATE TODAY ALL THE WAY THROUGH
TUESDAY MORNING AS HIGH-RESOLUTION MODEL CONDENSATE /SUCH AS THE
4KM SPC WRF/ SEEMS TO WORK BETTER IN SUCH A PATTERN WITH THIN BUT
PROBABLY BROKEN-OVERCAST CLOUD COVER. THE CLOUDS AND NORTH-
NORTHEAST WINDS ON TUESDAY MORNING SHOULD LIMIT WARMING BY QUITE A
BIT WITH SOME LOCATIONS POSSIBLY NOT REACHING 50.

AS THE COOLER AIR AT OR AROUND 0C AT 850MB EXPANDS SOUTHWARD DOWN
THE LAKE LATER TODAY FORESEE DEEPENING LAKE EFFECT CLOUDS AND
SOME SHOWERS DEVELOPING. THESE SHOWERS LOOK TO BE NOT PARTICULARLY
CONCENTRATED WITH LIMITED CONVERGENCE AND MAINLY LIGHT IN
INTENSITY WITH LAKE-INDUCED EQUILIBRIUM LEVELS FORECAST BY THE
NAM OF AROUND 5000 FT. THE BOUNDARY LAYER FLOW FETCH SHOULD FAVOR
NORTHWEST INDIANA FOR THESE SHOWERS TONIGHT INTO EARLY
TUESDAY...THOUGH SOME VEERING TOWARD THE IL/IN STATE LINE AND EVEN
POTENTIALLY CHICAGO TUESDAY MORNING COULD SUPPORT SOME LIGHT
SHOWER ACTIVITY TUESDAY MORNING IN THOSE PLACES. THE HOPWRF-TS
SUPPORTS SUCH A GENERAL EVOLUTION WITH ITS RECENTLY ADDED EXTENDED
HIGH-RES OUTPUT.

TUESDAY NIGHT THROUGH THURSDAY...
SURFACE HIGH PRESSURE WILL BUILD OVER THE AREA FROM THE NORTH DURING
THIS TIME AS THE OVERALL UPPER PATTERN SLOWS THANKS TO AMPLIFICATION
OF A TROUGH ALONG THE WEST COAST OF NORTH AMERICA. OVERALL BENIGN
WEATHER LOOKS TO BE THE RULE WITH TEMPS SLIGHTLY BELOW NORMAL THOUGH
GRADUALLY MODIFYING. MODEL GUIDANCE DOES INDICATE AN ELONGATED SHORT
WAVE TO MOVE INTO THE UPPER MISSISSIPPI VALLEY DURING OR AROUND
THURSDAY NIGHT THOUGH THIS WILL BE MOVING INTO AN UNFAVORABLE
UPPER LEVEL AND MOISTURE SUPPORTIVE PATTERN. SO CONTINUE THE DRY
FORECAST.

FRIDAY INTO NEXT WEEKEND...
THE ONLY CHANGE WITH THIS PORTION OF THE FORECAST WAS TO INCREASE
TEMPERATURES...MAINLY ON SATURDAY. IF CLOUD COVER CAN REMAIN LIMITED
WITH THE PATTERN FORECAST...THE 850MB-925MB TEMPERATURES WOULD
SUPPORT TEMPERATURES POTENTIALLY IN THE 70S WITH A THERMAL RIDGE
STEERED IN FROM THE WEST-SOUTHWEST.

MTF

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200809
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
309 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200809
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
309 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200809
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
309 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200809
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
309 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...

309 AM...LOW PRESSURE OVER THE UPPER PENINSULA OF MICHIGAN WILL
MOVE SOUTHEAST TODAY AND TONIGHT REACHING THE MID ATLANTIC ON
TUESDAY. A TRAILING COLD FRONT WILL MOVE ACROSS LAKE MICHIGAN THIS
MORNING. SOUTHWEST WINDS WILL TURN NORTHWEST THIS MORNING THEN
NORTH THIS EVENING. THE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE
SOUTHERN THIRD OR SO OF THE LAKE...WITH GUSTS TO 30KT POSSIBLE FOR
A FEW MORE HOURS. HIGH PRESSURE WILL BUILD ACROSS ONTARIO TODAY
AND TONIGHT AS IT STRENGTHENS. WHILE THE CENTER OF THIS HIGH WILL
MOVE EAST INTO QUEBEC TUESDAY NIGHT...A RIDGE WILL EXTEND SOUTH
ACROSS THE WESTERN LAKES TONIGHT AND TUESDAY...THEN MOVE ACROSS
THE LAKE WEDNESDAY. THE GRADIENT WILL TIGHTEN BETWEEN THIS
APPROACHING RIDGE AND THE DEPARTING LOW WITH NORTHERLY WINDS
INCREASING TO 30 KT THIS EVENING AND REMAINING THERE UNTIL TUESDAY
AFTERNOON...AS THE RIDGE SLOWLY WORKS EAST. CMS

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 7 AM MONDAY.

     SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...10 PM MONDAY TO 7 AM WEDNESDAY.

&&

$$

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 200729
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
229 AM CDT Mon Oct 20 2014

.SHORT TERM...(Today)
ISSUED AT 229 AM CDT MON OCT 20 2014

Latest surface analysis had low pressure centered over eastern Lake
Superior, with the trailing cold front extending southwest into the
central Plains. This low/front is being driven by a potent short
wave diving southeast across the upper Midwest/western Great Lakes.
However, despite the good forcing these features should provide, the
air mass the system is moving through is very dry. In fact, at the
moment, there is little/no cloud cover along the cold front once you
move away from the immediate vicinity of the surface low. There is
respectable WAA/isentropic lift over the southeast 1/3 of Illinois
ahead of the cold front, and this is resulting in a few sprinkles
breaking through from time to time from an AC deck around 10k feet.
This enhanced warm advection regime should shift south/east of the
forecast area by shortly after sunrise. So, do not expect measurable
rainfall ahead of the front today, although a few sprinkles will be
possible south of I-70 into the mid-morning hours.

The cold front should have cleared the forecast area by early
afternoon, with temperatures staying steady or slowly falling in its
wake. A strong low level inversion that is currently in place should
quickly erode in the post frontal cold advection. This may result in
a few hours of gusty northwest winds this afternoon.


&&

.LONG TERM...(Tonight through Sunday)
ISSUED AT 229 AM CDT MON OCT 20 2014

Once the current system passes, the remainder of the week looks to
be fairly quiet. The upper ridge currently along the east slopes of
the Rockies will shift eastward into the Mississippi Valley by mid
week, with dry weather prevailing. The main forecast issue involves
Thursday, as the ridge erodes between an incoming wave from the
northern Plains, and a large upper low that will slowly wobble
through the mid-Atlantic states. The general consensus over the last
few model runs was that the associated shower activity would have
difficulty crossing the Mississippi River into Illinois, but the
latest GFS and ECMWF do bring some diminishing showers across the
north half of the state Thursday afternoon/evening as an upper low
develops and slides into northern Wisconsin. Have kept the forecast
dry for now, but will monitor to see if this is a persistent trend
before introducing into the forecast.

A nice warming trend is on tap toward late week, as thermal ridging
extends east from the central Plains. 850 mb temperatures progged to
rise to around 16C by Saturday afternoon, which would bring surface
temperatures to around 70 degrees in many areas.


&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1157 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. The rest
of the night, a band of AC and cirrus will continue to advance
ESE across the area. PIA should be north of the clouds for the
most part, while BMI/SPI will be on the northern periphery.
DEC/CMI will be closer to some possible sprinkles as the first of
two shortwaves enhances lift across our southeast area. There
remains some potential for cloud heights to approach MVFR for DEC
and CMI late tonight and early tomorrow morning ahead of the
second trough, but the lowest cloud heights in that time frame
should be around 3500-4000 FT. Forecast soundings show an increase
of moisture in the 3.5-5K ft level tomorrow afternoon, so periodic
lower clouds will be possible tomorrow afternoon and evening.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.


&&

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

$$

SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Shimon







000
FXUS63 KLOT 200524
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1224 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM MONDAY.

&&

$$

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 200524
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1224 AM CDT MON OCT 20 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS BECOME WEST THIS MORNING...NORTHWEST THIS
  AFTERNOON THEN NORTH/NORTHEAST LATE THIS AFTERNOON. CMS

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

A COLD FRONT WILL MOVE ACROSS THE TERMINALS LATER THIS MORNING...
SHIFTING SOUTHWESTERLY WINDS TO THE WEST/NORTHWEST BY MID MORNING
AND THEN TO THE NORTHWEST BY EARLY AFTERNOON. SPEEDS 10-12KTS WITH
A FEW HIGHER GUSTS TO START WILL DIMINISH SOME BY SUNRISE THEN
INCREASE AGAIN TO 10-12KTS THIS AFTERNOON. AS THE FRONT CONTINUES
EAST THIS AFTERNOON...THE GRADIENT BECOMES A BIT WEAKER OVER THE
SOUTHERN END OF LAKE MICHIGAN. THIS WILL LIKELY ALLOW WINDS TO
SHIFT TO THE NORTH/NORTHEAST BY LATE AFTERNOON. CONFIDENCE IN
SPEEDS IS A BIT LOWER...WITH PREVAILING SPEEDS LIKELY TO BE JUST
UNDER 10KTS.

MID CLOUDS WILL SHIFT EAST EARLY THIS MORNING WITH LOWER VFR...
3-5KFT CIGS OVER THE NORTHERN LAKES MOVING SOUTH ACROSS THE AREA
LATER THIS MORNING AND CONTINUING INTO THIS EVENING WITH SOME
POTENTIAL FOR HIGH MVFR CIGS...ESPECIALLY SOUTH OF THE LAKE
AFFECTING GYY. CMS

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

HIGH FOR WINDS THRU MID MORNING...THEN MEDIUM FOR DIRECTION AND
TIMING CHANGES THIS AFTERNOON/EVENING. CMS

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 3 AM MONDAY.

&&

$$

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 200457
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1157 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 900 PM CDT SUN OCT 19 2014

A band of mid and high clouds will progress to the ESE across IL
the rest of the evening and just after midnight. The clouds are
associated with a weak shortwave in the 500mb flow. Moisture will
be scarce, so precip will be limited, and mainly confined to areas
southeast of a line from Taylorville to Paris after 08z/2am
tonight. A stronger shortwave arriving with the upper trough axis
tomorrow will help keep slight precip chances in roughly that
same area through 18z/1pm tomorrow. Sprinkles and light showers
will be the main result, with no thunder expected.

As for temps tonight, a continuation of the SW surface winds will
provide slightly warmer conditions, with lows in the upper 40s to
low 50s in most areas. The warm surge will continue through the
morning tomorrow, helping push high temps into the mid to upper
60s, before the cold front passes and winds shift to the WNW and
cooling begins.

Only minor adjustments were needed to the sky and hourly temp
forecasts, so no formal product updates will be needed this eve.

&&

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1157 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. The rest
of the night, a band of AC and cirrus will continue to advance
ESE across the area. PIA should be north of the clouds for the
most part, while BMI/SPI will be on the northern periphery.
DEC/CMI will be closer to some possible sprinkles as the first of
two shortwaves enhances lift across our southeast area. There
remains some potential for cloud heights to approach MVFR for DEC
and CMI late tonight and early tomorrow morning ahead of the
second trough, but the lowest cloud heights in that time frame
should be around 3500-4000 FT. Forecast soundings show an increase
of moisture in the 3.5-5K ft level tomorrow afternoon, so periodic
lower clouds will be possible tomorrow afternoon and evening.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon






000
FXUS63 KILX 200457
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1157 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 900 PM CDT SUN OCT 19 2014

A band of mid and high clouds will progress to the ESE across IL
the rest of the evening and just after midnight. The clouds are
associated with a weak shortwave in the 500mb flow. Moisture will
be scarce, so precip will be limited, and mainly confined to areas
southeast of a line from Taylorville to Paris after 08z/2am
tonight. A stronger shortwave arriving with the upper trough axis
tomorrow will help keep slight precip chances in roughly that
same area through 18z/1pm tomorrow. Sprinkles and light showers
will be the main result, with no thunder expected.

As for temps tonight, a continuation of the SW surface winds will
provide slightly warmer conditions, with lows in the upper 40s to
low 50s in most areas. The warm surge will continue through the
morning tomorrow, helping push high temps into the mid to upper
60s, before the cold front passes and winds shift to the WNW and
cooling begins.

Only minor adjustments were needed to the sky and hourly temp
forecasts, so no formal product updates will be needed this eve.

&&

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1157 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. The rest
of the night, a band of AC and cirrus will continue to advance
ESE across the area. PIA should be north of the clouds for the
most part, while BMI/SPI will be on the northern periphery.
DEC/CMI will be closer to some possible sprinkles as the first of
two shortwaves enhances lift across our southeast area. There
remains some potential for cloud heights to approach MVFR for DEC
and CMI late tonight and early tomorrow morning ahead of the
second trough, but the lowest cloud heights in that time frame
should be around 3500-4000 FT. Forecast soundings show an increase
of moisture in the 3.5-5K ft level tomorrow afternoon, so periodic
lower clouds will be possible tomorrow afternoon and evening.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KLOT 200302
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1002 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE EVENING.

* SOUTHWEST WINDS SHIFT NORTHWEST MONDAY MORNING.

* SCT-BKN LOW END VFR CLOUDS MONDAY.

MDB

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

HIGH PRESSURE IS OFF TO THE EAST WITH LOW PRESSURE MOVING EASTWARD
ACROSS LAKE SUPERIOR WHICH WILL KEEP A STEADY SOUTHWEST WIND IN
PLACE THROUGH THE EVENING. SPEEDS WILL PROBABLY SETTLE SLIGHTLY
EARLY BUT EXPECT THEM TO COME UP A BIT AS THE PRESSURE GRADIENT
TIGHTENS. OCCASIONAL GUSTS ARE ALSO POSSIBLE. A COOL FRONT WILL
CROSS THE AREA MONDAY MORNING AS THE LOW CONTINUES EAST WHICH WILL
TURN WINDS NORTHWESTERLY. THE GRADIENT WILL WEAKEN SO SPEEDS WILL
LIKELY HOVER AROUND 10 KT MONDAY. LOW LEVEL MOISTURE IS FORECAST
TO INCREASE BEHIND THE FRONT...ESPECIALLY MONDAY AFTERNOON. EXPECT
THAT LOWER END VFR CIGS WILL MOVE IN WITH SCT-BKN COVERAGE.

MDB

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

* HIGH CONFIDENCE IN WIND TRENDS.

* MEDIUM CONFIDENCE IN LOWER END VFR CIGS MONDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 200302
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1002 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE EVENING.

* SOUTHWEST WINDS SHIFT NORTHWEST MONDAY MORNING.

* SCT-BKN LOW END VFR CLOUDS MONDAY.

MDB

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

HIGH PRESSURE IS OFF TO THE EAST WITH LOW PRESSURE MOVING EASTWARD
ACROSS LAKE SUPERIOR WHICH WILL KEEP A STEADY SOUTHWEST WIND IN
PLACE THROUGH THE EVENING. SPEEDS WILL PROBABLY SETTLE SLIGHTLY
EARLY BUT EXPECT THEM TO COME UP A BIT AS THE PRESSURE GRADIENT
TIGHTENS. OCCASIONAL GUSTS ARE ALSO POSSIBLE. A COOL FRONT WILL
CROSS THE AREA MONDAY MORNING AS THE LOW CONTINUES EAST WHICH WILL
TURN WINDS NORTHWESTERLY. THE GRADIENT WILL WEAKEN SO SPEEDS WILL
LIKELY HOVER AROUND 10 KT MONDAY. LOW LEVEL MOISTURE IS FORECAST
TO INCREASE BEHIND THE FRONT...ESPECIALLY MONDAY AFTERNOON. EXPECT
THAT LOWER END VFR CIGS WILL MOVE IN WITH SCT-BKN COVERAGE.

MDB

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

* HIGH CONFIDENCE IN WIND TRENDS.

* MEDIUM CONFIDENCE IN LOWER END VFR CIGS MONDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 200207
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
907 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 900 PM CDT SUN OCT 19 2014

A band of mid and high clouds will progress to the ESE across IL
the rest of the evening and just after midnight. The clouds are
associated with a weak shortwave in the 500mb flow. Moisture will
be scarce, so precip will be limited, and mainly confined to areas
southeast of a line from Taylorville to Paris after 08z/2am
tonight. A stronger shortwave arriving with the upper trough axis
tomorrow will help keep slight precip chances in roughly that
same area through 18z/1pm tomorrow. Sprinkles and light showers
will be the main result, with no thunder expected.

As for temps tonight, a continuation of the SW surface winds will
provide slightly warmer conditions, with lows in the upper 40s to
low 50s in most areas. The warm surge will continue through the
morning tomorrow, helping push high temps into the mid to upper
60s, before the cold front passes and winds shift to the WNW and
cooling begins.

Only minor adjustments were needed to the sky and hourly temp
forecasts, so no formal product updates will be needed this eve.

&&

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KILX 200207
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
907 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 900 PM CDT SUN OCT 19 2014

A band of mid and high clouds will progress to the ESE across IL
the rest of the evening and just after midnight. The clouds are
associated with a weak shortwave in the 500mb flow. Moisture will
be scarce, so precip will be limited, and mainly confined to areas
southeast of a line from Taylorville to Paris after 08z/2am
tonight. A stronger shortwave arriving with the upper trough axis
tomorrow will help keep slight precip chances in roughly that
same area through 18z/1pm tomorrow. Sprinkles and light showers
will be the main result, with no thunder expected.

As for temps tonight, a continuation of the SW surface winds will
provide slightly warmer conditions, with lows in the upper 40s to
low 50s in most areas. The warm surge will continue through the
morning tomorrow, helping push high temps into the mid to upper
60s, before the cold front passes and winds shift to the WNW and
cooling begins.

Only minor adjustments were needed to the sky and hourly temp
forecasts, so no formal product updates will be needed this eve.

&&

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.


&&

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

$$

UPDATE...Shimon
SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon






000
FXUS63 KLOT 200003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
703 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE EVENING.

* SOUTHWEST WINDS SHIFT NORTHWEST MONDAY MORNING.

* SCT-BKN LOW END VFR CLOUDS MONDAY.

MDB

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

HIGH PRESSURE IS OFF TO THE EAST WITH LOW PRESSURE MOVING EASTWARD
ACROSS LAKE SUPERIOR WHICH WILL KEEP A STEADY SOUTHWEST WIND IN
PLACE THROUGH THE EVENING. SPEEDS WILL PROBABLY SETTLE SLIGHTLY
EARLY BUT EXPECT THEM TO COME UP A BIT AS THE PRESSURE GRADIENT
TIGHTENS. OCCASIONAL GUSTS ARE ALSO POSSIBLE. A COOL FRONT WILL
CROSS THE AREA MONDAY MORNING AS THE LOW CONTINUES EAST WHICH WILL
TURN WINDS NORTHWESTERLY. THE GRADIENT WILL WEAKEN SO SPEEDS WILL
LIKELY HOVER AROUND 10 KT MONDAY. LOW LEVEL MOISTURE IS FORECAST
TO INCREASE BEHIND THE FRONT...ESPECIALLY MONDAY AFTERNOON. EXPECT
THAT LOWER END VFR CIGS WILL MOVE IN WITH SCT-BKN COVERAGE.

MDB


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

* HIGH CONFIDENCE IN WIND TRENDS BUT MEDIUM CONFIDENCE IN GUSTS
  CONTINUING THIS EVENING.

* MEDIUM CONFIDENCE IN LOWER END VFR CIGS MONDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 200003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
703 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE EVENING.

* SOUTHWEST WINDS SHIFT NORTHWEST MONDAY MORNING.

* SCT-BKN LOW END VFR CLOUDS MONDAY.

MDB

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

HIGH PRESSURE IS OFF TO THE EAST WITH LOW PRESSURE MOVING EASTWARD
ACROSS LAKE SUPERIOR WHICH WILL KEEP A STEADY SOUTHWEST WIND IN
PLACE THROUGH THE EVENING. SPEEDS WILL PROBABLY SETTLE SLIGHTLY
EARLY BUT EXPECT THEM TO COME UP A BIT AS THE PRESSURE GRADIENT
TIGHTENS. OCCASIONAL GUSTS ARE ALSO POSSIBLE. A COOL FRONT WILL
CROSS THE AREA MONDAY MORNING AS THE LOW CONTINUES EAST WHICH WILL
TURN WINDS NORTHWESTERLY. THE GRADIENT WILL WEAKEN SO SPEEDS WILL
LIKELY HOVER AROUND 10 KT MONDAY. LOW LEVEL MOISTURE IS FORECAST
TO INCREASE BEHIND THE FRONT...ESPECIALLY MONDAY AFTERNOON. EXPECT
THAT LOWER END VFR CIGS WILL MOVE IN WITH SCT-BKN COVERAGE.

MDB


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

* HIGH CONFIDENCE IN WIND TRENDS BUT MEDIUM CONFIDENCE IN GUSTS
  CONTINUING THIS EVENING.

* MEDIUM CONFIDENCE IN LOWER END VFR CIGS MONDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 200003
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
703 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE EVENING.

* SOUTHWEST WINDS SHIFT NORTHWEST MONDAY MORNING.

* SCT-BKN LOW END VFR CLOUDS MONDAY.

MDB

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

HIGH PRESSURE IS OFF TO THE EAST WITH LOW PRESSURE MOVING EASTWARD
ACROSS LAKE SUPERIOR WHICH WILL KEEP A STEADY SOUTHWEST WIND IN
PLACE THROUGH THE EVENING. SPEEDS WILL PROBABLY SETTLE SLIGHTLY
EARLY BUT EXPECT THEM TO COME UP A BIT AS THE PRESSURE GRADIENT
TIGHTENS. OCCASIONAL GUSTS ARE ALSO POSSIBLE. A COOL FRONT WILL
CROSS THE AREA MONDAY MORNING AS THE LOW CONTINUES EAST WHICH WILL
TURN WINDS NORTHWESTERLY. THE GRADIENT WILL WEAKEN SO SPEEDS WILL
LIKELY HOVER AROUND 10 KT MONDAY. LOW LEVEL MOISTURE IS FORECAST
TO INCREASE BEHIND THE FRONT...ESPECIALLY MONDAY AFTERNOON. EXPECT
THAT LOWER END VFR CIGS WILL MOVE IN WITH SCT-BKN COVERAGE.

MDB


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

* HIGH CONFIDENCE IN WIND TRENDS BUT MEDIUM CONFIDENCE IN GUSTS
  CONTINUING THIS EVENING.

* MEDIUM CONFIDENCE IN LOWER END VFR CIGS MONDAY.

MDB

//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...

TUESDAY...VFR. BREEZY NORTHEAST WINDS.

WEDNESDAY...VFR. EAST WINDS.

THURSDAY THROUGH SATURDAY...VFR. LIGHT WEST TO SOUTHWEST WINDS.

MDB

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon






000
FXUS63 KILX 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KILX 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KILX 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KILX 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KILX 192359
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
659 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.

&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 659 PM CDT SUN OCT 19 2014

VFR conditions are expected over the next 24 hours despite a
surface trough forecast to move across the area tomorrow. This
evening, a band of AC and Cirrus will advance across the terminals,
with the lowest clouds around 9K FT. Cloud heights will approach
MVFR later tonight and early tomorrow morning ahead of the trough,
but the lowest cloud heights in that time frame should be around
3500 FT. Forecast soundings show moisture in the 3.5-5K ft level
will linger into the afternoon, so periodic lower clouds will be
possible.

Winds will start out SW from 7-9KT, then become W-NW tomorrow
morning behind the surface trough while increasing to 10-12kt.

&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Shimon







000
FXUS63 KLOT 192210
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
510 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* SOUTHWEST WINDS OCCASIONALLY GUSTING TO AROUND 20 KT THROUGH THE
  EVENING.

MDB

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLINOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE IN WIND TRENDS...MEDIUM CONFIDENCE IN OCCASIONAL
  GUSTS CONTINUING THROUGH THE EVENING.

MDB

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTHERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
     UNTIL 3 AM MONDAY.

&&

$$

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 192030
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 192030
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 192030
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 192030
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
330 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
324 PM CDT

LOW PRESSURE MOVING THROUGH ONTARIO TONIGHT WILL DRAG A COLD
FRONT ACROSS THE LAKE AND TIGHTEN THE PRESSURE GRADIENT THIS
EVENING. GALE FORCE GUSTS ARE POSSIBLE FOR A TIME BUT GENERALLY
WINDS SHOULD STAY BELOW GALE WARNING CRITERIA. A SMALL CRAFT
ADVISORY CONTINUES FOR NEARSHORE WATERS THIS EVENING AND THROUGH
THE EARLY OVERNIGHT HOURS DUE TO STRONG OFFSHORE WINDS...BUT WAVES
SHOULD NOT BE A BIG PROBLEM UNTIL WINDS TURN NORTHWEST AND THEN
NORTH BY LATE MONDAY...INCREASING AGAIN IN A GRADIENT BETWEEN AN
APPROACHING HIGH AND THE SLOWLY DEPARTING LOW. THESE STRONG
NORTERLY WINDS PERSIST THROUGH TUESDAY AFTER WHICH TIME THE RIDGE
MOVES OVER THE LAKE BRINGING FAIRLY QUIET CONDITIONS.

LENNING

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING


KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191955
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
255 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

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

* GUSTY SW WINDS THROUGH THIS EVENING


KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

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

* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191935
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
235 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.


&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.


&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes







000
FXUS63 KILX 191935
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
235 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.


&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.


&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes







000
FXUS63 KILX 191935
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
235 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.


&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.


&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes







000
FXUS63 KILX 191935
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
235 PM CDT Sun Oct 19 2014

.SHORT TERM...(Tonight)
ISSUED AT 234 PM CDT SUN OCT 19 2014

12z KILX upper air sounding showed a very strong subsidence
inversion around 900mb, with a layer of surface-based moisture
trapped beneath it.  Due to a lack of adequate mixing with the much
drier airmass aloft, low clouds have persisted/developed across the
area today.  18z/1pm visible satellite imagery showed these clouds
along/east of the I-55 corridor.  Surface high pressure has shifted
into the Ohio River Valley, so S/SW winds on its back side are
finally beginning to push the clouds off to the east.  Am expecting
the clouds to gradually dissipate/shift eastward over the next
couple of hours, with mostly clear skies across the board by late
afternoon/early evening.

Next upper short-wave to impact the weather across central Illinois
is evident on water vapor imagery over Manitoba.  As this feature
drops southeastward, it will push a weak frontal boundary into the
region late tonight into early Monday morning.  Forecast soundings
remain quite dry ahead of the front and 12z models have therefore
backed way off on precip development.  Lead short-wave will bring
increasing high clouds to central Illinois this evening, then main
wave may bring lower/thicker clouds into the picture overnight.
Given dry soundings and best lift associated with Manitoba wave
skirting by to the N/NE, will only carry slight chance PoPs across
the southeast CWA after midnight.  May see a few sprinkles further
north, but measurable precip is not expected.


&&

.LONG TERM...(Monday through Sunday)
ISSUED AT 234 PM CDT SUN OCT 19 2014

After the short wave and weak frontal boundary, a mid level ridge
and surface high pressure will build into the region with dry
conditions. This will continue into Thur as the CWA remains in a
somewhat anti-cyclonic flow. Models then begin to bring another wave
toward the region Thursday. Models differ on what happens to this
wave as the ridge gets pinched off between the approaching wave and
the large low sitting over the northeastern US. The GFS takes the
energy north while the ECMWF takes it to the north and south. Either
way, central IL will remain dry through the rest of the week. Then
pushing into the weekend, ridging returns with dry weather.

Warmest temps will be tomorrow ahead of the short wave. Then behind
it, slightly cooler temps are expected. Temps will remain below
normal through the rest of the week, and then warm for the weekend.


&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.


&&

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

$$

SHORT TERM...Barnes
LONG TERM...Auten
AVIATION...Barnes







000
FXUS63 KLOT 191853
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
153 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* BRIEF PERIOD OF BROKEN MVFR CIGS THIS AFTERNOON
* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE IN MVFR OCCURRENCE AND DURATION THIS AFTERNOON.
* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191853
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
153 PM CDT SUN OCT 19 2014

.DISCUSSION...
152 PM CDT

TONIGHT...
VISIBLE IMAGERY THIS AFTERNOON INDICATES A THIN CIRRUS SHIELD OVER
THE REGION...WITH SOME ENHANCEMENT TO THE CLOUD COVER ACROSS
WISCONSIN AHEAD OF A FRONTAL BOUNDARY THAT IS PUSHING FROM WEST TO
EAST ACROSS THE WESTERN GREAT LAKES. SFC RIDGE HAS DRIFTED SOUTHEAST
OF THE FORECAST AREA...WHICH HAS ALLOWED LLVL FLOW TO TURN
SOUTHWESTERLY. BETWEEN THE NEXT RIDGE OF HIGH PRESSURE AND THE
DEPARTING RIDGE...WEAK TROUGHING WILL SLIDE EAST ACROSS THE UPPER
MIDWEST/GREAT LAKES. THIS HAS PRODUCED A BUMP IN THE GRADIENT AND
RESULTED IN BREEZY CONDS THIS AFTN FROM A GOOD MIXED LAYER.

GUIDANCE HAS SLOWED THE ARRIVAL OF THE FRONTAL BOUNDARY
SLIGHTLY...BUT THERE REMAINS SOME CONSISTENCY THAT THE
MOISTURE/PRECIP WILL BE DISPLACED TO THE NORTHEAST OF THE FORECAST
AREA THRU THE OVERNIGHT PERIOD. TEMPS TONIGHT WILL BE WARMER THAN
THE PRIOR NGT WITH LOWS GENERALLY IN THE LOW/MID 40S.

MONDAY THROUGH THURSDAY...
500MB TROUGH AXIS WILL CONTINUE TO PIVOT EAST OF THE REGION BY
MIDDAY MON...HOWEVER THERE DOES APPEAR TO BE SOME WRAP AROUND
MOISTURE TRYING TO SLIDE SOUTH ACROSS THE LAKE AND MAY PRODUCE SOME
SPRINKLES/LGT RAIN FOR NORTHWEST IN. HAVE MAINTAINED A DRY FORECAST
FOR NORTHEAST IL...HOWEVER LATE MON EVE A FEW SPOTTY SHOWERS COULD
SNEAK INTO THE CHICAGO METRO AREA INTO TUE MORNING. OTHERWISE EXPECT
THE FAR WESTERN FORECAST AREA TO REMAIN DRY. THEN BROAD
ANTI-CYCLONIC FLOW ARRIVES AND IS EXPECTED TO REMAIN IN PLACE THRU
THE SECOND HALF OF THE WEEK. TEMPS MON WILL LIKELY BE THE WARMEST IN
THE UPR 50S TO LOW 60S...THEN COOLING INTO THE LOW/MID 50S FOR
TUE/WED/THUR. WITH HIGH PRES POISED TO BE OVERHEAD TUE
NGT-WED-NGT...LOWS IN MANY AREAS COULD EASILY DIP INTO THE MID 30S.

FRIDAY THROUGH NEXT WEEKEND...
ENSEMBLES CONTINUE WITH THE RATHER BENIGN PATTERN INTO THE WEEKEND.
TROUGH DIGS INTO THE SOUTHWEST CONUS...BUT IS PROGGED TO WEAKEN BY
SAT/SUN. HIGH AMPLITUDE RIDGING OVER THE CENTRAL CONUS WILL
GRADUALLY WEAKEN LATE IN THE WEEK...HOWEVER CURRENT GUIDANCE
SUGGESTS THE DRY PATTERN WILL PERSIST INTO AT LEAST SAT. TEMPS WILL
STEADILY RETURN TO NEAR SEASONAL CONDS WITH HIGHS ARND 60 TO THE LOW
60S BY THE WEEKEND.

BEACHLER

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* BRIEF PERIOD OF BROKEN MVFR CIGS THIS AFTERNOON
* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD

//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE IN MVFR OCCURRENCE AND DURATION THIS AFTERNOON.
* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191741
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1241 PM CDT SUN OCT 19 2014

.DISCUSSION...

320 AM...FAIRLY QUIET WEATHER EXPECTED THROUGH THE END OF THE WEEK
WITH A CHANCE OF A SHOWER OR SPRINKLES TONIGHT AND THEN LAKE
EFFECT RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.

LOWER CLOUDS HAVE CLEARED ALL BUT FAR EASTERN CWA...AND WILL BE
CLEARING THERE BEFORE SUNRISE. WITH CALM WINDS AS HIGH PRESSURE
MOVES SOUTHEAST ACROSS THE AREA...TEMPS HAVE DROPPED INTO THE
LOWER TO MID 30S MOST AREAS AND THE FROST ADVISORY AND ITS TIMING
IS ON TRACK. SOME PATCHY/SHALLOW GROUND FOG HAS DEVELOPED AND NOT
EXPECTING THIS TO BECOME WIDESPREAD.

LOW PRESSURE WILL MOVE SOUTHEAST FROM MANITOBA TODAY REACHING THE
NORTHERN LAKES TONIGHT. THE GRADIENT WILL TIGHTEN SOME BETWEEN
THIS LOW AND THE DEPARTING HIGH WITH BREEZY SOUTHWEST WINDS AT
TIMES...MAINLY ACROSS THE NORTHERN CWA. SHOULD BE A FAIR AMOUNT OF
SUNSHINE TO START BUT INCREASING MID/HIGH CLOUDS THIS AFTERNOON
INTO THIS EVENING. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE
ACROSS THE AREA TONIGHT WITH LIMITED FORCING/MOISTURE. BETTER
CHANCES FOR SHOWERS OR SPRINKLES WILL LIKELY REMAIN BOTH NORTH AND
SOUTH OF THE CWA AND REMOVED MENTIONABLE POPS.

AS COLDER AIR SPREADS ACROSS THE REGION MONDAY AFTERNOON INTO
MONDAY NIGHT...LAKE EFFECT RAIN SHOWERS ARE EXPECTED TO DEVELOP
OVER SOUTHERN LAKE MICHIGAN AND AFFECT MAINLY NORTHWEST INDIANA
BUT AS HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES TUESDAY...
ITS POSSIBLE WINDS MAY TURN ENOUGH TO THE NORTHEAST FOR A FEW RAIN
SHOWERS TO REACH EASTERN COOK COUNTY TUESDAY MORNING...BEFORE THE
PRECIP DISSIPATES AS THE HIGH BUILDS SOUTHEAST ACROSS THE REGION.

THIS HIGH WILL MAINTAIN DRY AND QUIET WEATHER WEDNESDAY AND
THURSDAY WITH ANOTHER WAVE MOVING ACROSS THE PLAINS THURSDAY AND
POSSIBLY REACHING THE AREA THURSDAY NIGHT OR FRIDAY BUT MODELS
WEAKEN THIS CONSIDERABLY SHOWING NO PRECIP REACHING THE CWA. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 18Z...

* BRIEF PERIOD OF BROKEN MVFR CIGS THIS AFTERNOON
* GUSTY SW WINDS THROUGH THIS EVENING

KMD

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

WE HAVE SEEN AN EXPANSION OF MVFR CLOUDS FROM THE SOUTH AND WEST
THIS AFTERNOON. AS DAYTIME HEATING CONTINUES THESE CLOUDS ARE
BREAKING UP SOME AS THEY MIGRATE TO THE EAST AND THE BACK EDGE OF
THE BROKEN CLOUDS IS NOW REACHING A LINE FROM KRPJ TO KDKB...THOUGH
THERE WILL LIKELY BE AT LEAST A BRIEF PERIOD THIS AFTERNOON OF
MVFR CIGS FOR THE CHICAGOLAND TERMINALS.

CONCERNS SHIFT TO WIND SPEEDS THIS AFTERNOON AND EVENING AS LOW
PRESSURE SPREADS TO NORTHERN LAKE MICHIGAN AND A MODEST PRESSURE
GRADIENT SETS UP THROUGH NE ILLNOIS AHEAD OF A COLD FRONT. WIND
SPEEDS AT 2000 FT WILL PUSH 40 KT. NORMALLY WE WOULD SEE WINDS
EASE AT THE SURFACE AT NIGHT BUT THINKING THAT WE WILL CONTINUE TO
SEE WIND GUSTS THROUGH THE EVENING...LIKELY EVEN INCREASING OVER
THIS AFTERNOON. IF THEY DON`T SURFACE THEN THERE MAY BE A PERIOD
OF LOW LEVEL WIND SPEED SHEAR. GRADIENT SLACKENS SOME AFTER
MIDNIGHT THEN A COLD FRONT BRINGS A SHIFT TO NW WIND. NAM IS
SUGGESTING A BUNCH OF LOW CLOUDS IN THE MORNING BUT NOT BUYING OFF
ON THAT AT THE MOMENT. KMD

KMD


//ORD AND MDW CONFIDENCE...UPDATED 18Z...

* MEDIUM CONFIDENCE IN MVFR OCCURRENCE AND DURATION THIS AFTERNOON.
* HIGH CONFIDENCE WIND TRENDS...THOUGH LOW-MEDIUM CONFIDENCE ON
  WIND GUST POTENTIAL THIS EVENING.

KMD

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191734
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1234 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.

&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Barnes






000
FXUS63 KILX 191734
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1234 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.

&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Barnes






000
FXUS63 KILX 191734
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1234 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.

&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Barnes






000
FXUS63 KILX 191734
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1234 PM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 1234 PM CDT SUN OCT 19 2014

MVFR ceilings persist at the central Illinois terminals early this
afternoon as low-level moisture remains trapped below a strong
subsidence inversion. Moisture has been very slowly shifting
eastward over the past couple of hours, and latest HRRR continues
this trend through the afternoon. Based on satellite timing tools,
will scatter the ceilings at KSPI by 19z, then further east to KCMI
by around 21z. Once low clouds clear out, quite a bit of high
cirrus clouds will stream across the area this afternoon/evening
in advance of a trough axis currently extending from Minnesota to
Nebraska. Latest satellite and regional obs indicate only mid/high
clouds associated with this boundary: however, as it drops
southeastward later tonight into Monday morning, most models are
showing a marked increase in 1000-850mb RH. Soundings remain
rather dry, so am expecting little more than a few sprinkles early
Monday morning. However, have included low VFR ceilings at all
sites except KPIA and KSPI as the boundary passes. After that,
winds will veer to the W/NW and skies will clear toward midday.

&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Barnes






000
FXUS63 KLOT 191617
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1117 AM CDT SUN OCT 19 2014

.DISCUSSION...

320 AM...FAIRLY QUIET WEATHER EXPECTED THROUGH THE END OF THE WEEK
WITH A CHANCE OF A SHOWER OR SPRINKLES TONIGHT AND THEN LAKE
EFFECT RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.

LOWER CLOUDS HAVE CLEARED ALL BUT FAR EASTERN CWA...AND WILL BE
CLEARING THERE BEFORE SUNRISE. WITH CALM WINDS AS HIGH PRESSURE
MOVES SOUTHEAST ACROSS THE AREA...TEMPS HAVE DROPPED INTO THE
LOWER TO MID 30S MOST AREAS AND THE FROST ADVISORY AND ITS TIMING
IS ON TRACK. SOME PATCHY/SHALLOW GROUND FOG HAS DEVELOPED AND NOT
EXPECTING THIS TO BECOME WIDESPREAD.

LOW PRESSURE WILL MOVE SOUTHEAST FROM MANITOBA TODAY REACHING THE
NORTHERN LAKES TONIGHT. THE GRADIENT WILL TIGHTEN SOME BETWEEN
THIS LOW AND THE DEPARTING HIGH WITH BREEZY SOUTHWEST WINDS AT
TIMES...MAINLY ACROSS THE NORTHERN CWA. SHOULD BE A FAIR AMOUNT OF
SUNSHINE TO START BUT INCREASING MID/HIGH CLOUDS THIS AFTERNOON
INTO THIS EVENING. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE
ACROSS THE AREA TONIGHT WITH LIMITED FORCING/MOISTURE. BETTER
CHANCES FOR SHOWERS OR SPRINKLES WILL LIKELY REMAIN BOTH NORTH AND
SOUTH OF THE CWA AND REMOVED MENTIONABLE POPS.

AS COLDER AIR SPREADS ACROSS THE REGION MONDAY AFTERNOON INTO
MONDAY NIGHT...LAKE EFFECT RAIN SHOWERS ARE EXPECTED TO DEVELOP
OVER SOUTHERN LAKE MICHIGAN AND AFFECT MAINLY NORTHWEST INDIANA
BUT AS HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES TUESDAY...
ITS POSSIBLE WINDS MAY TURN ENOUGH TO THE NORTHEAST FOR A FEW RAIN
SHOWERS TO REACH EASTERN COOK COUNTY TUESDAY MORNING...BEFORE THE
PRECIP DISSIPATES AS THE HIGH BUILDS SOUTHEAST ACROSS THE REGION.

THIS HIGH WILL MAINTAIN DRY AND QUIET WEATHER WEDNESDAY AND
THURSDAY WITH ANOTHER WAVE MOVING ACROSS THE PLAINS THURSDAY AND
POSSIBLY REACHING THE AREA THURSDAY NIGHT OR FRIDAY BUT MODELS
WEAKEN THIS CONSIDERABLY SHOWING NO PRECIP REACHING THE CWA. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* GUSTY SW WINDS THIS AFTERNOON.
* MVFR CIGS THIS AFTERNOON

KMD

//DISCUSSION...UPDATED 16Z...

MVFR CIGS EXPANDING TO THE SOUTH AND WEST...BUT THEY HAVE MADE IT
INTO KRPJ AND KDKB. NAM AND RAP MODELS SUGGEST AT LEAST A PERIOD
OF SCATTERED MVFR CLOUDS...POSSIBLY BROKEN THIS AFTERNOON. WILL
TAKE A CLOSE LOOK AT THIS FOR THE 18Z TAF CYCLE.

KMD

PREVIOUS DISCUSSION FROM 12Z FOLLOWS...

PATCHY GROUND FOG IN RURAL AREAS WILL QUICKLY DISSIPATE EARLY THIS
MORNING WITH SOUTHWEST WINDS DEVELOPING AND GRADUALLY INCREASING.
WILL LIKELY BE SOME AT LEAST SPORIDIC GUSTINESS THIS
AFTERNOON...THOUGH INCREASING CLOUD COVER COULD LIMIT THE DURATION
AND INTENSITY OF THE GUSTS SOME. WINDS AROUND 2000FT AGL INCREASE
TO 35-40KT FOR A TIME THIS EVENING...THOUGH EXPECT ENOUGH MIXING
IN THE LOW LEVEL AND STRONG ENOUGH SFC WINDS TO PRECLUDE A BIG
LLWS PROBLEM. FRONT WILL SHIFT WINDS TO THE NORTHWEST MONDAY
MORNING BUT LITTLE THREAT OF ANY PRECIP EXISTS WITH THE FRONTAL
PASSAGE. OTHER THAN THIS MORNING`S RURAL GROUND FOG LOOK FOR VFR
CONDITIONS THROUGH THE TAF CYCLE.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE WIND TRENDS
* LOW-MEDIUM CONFIDENCE IN MVFR REMAINING SCATTERED AT ORD/MDW

IZZI

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191617
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1117 AM CDT SUN OCT 19 2014

.DISCUSSION...

320 AM...FAIRLY QUIET WEATHER EXPECTED THROUGH THE END OF THE WEEK
WITH A CHANCE OF A SHOWER OR SPRINKLES TONIGHT AND THEN LAKE
EFFECT RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.

LOWER CLOUDS HAVE CLEARED ALL BUT FAR EASTERN CWA...AND WILL BE
CLEARING THERE BEFORE SUNRISE. WITH CALM WINDS AS HIGH PRESSURE
MOVES SOUTHEAST ACROSS THE AREA...TEMPS HAVE DROPPED INTO THE
LOWER TO MID 30S MOST AREAS AND THE FROST ADVISORY AND ITS TIMING
IS ON TRACK. SOME PATCHY/SHALLOW GROUND FOG HAS DEVELOPED AND NOT
EXPECTING THIS TO BECOME WIDESPREAD.

LOW PRESSURE WILL MOVE SOUTHEAST FROM MANITOBA TODAY REACHING THE
NORTHERN LAKES TONIGHT. THE GRADIENT WILL TIGHTEN SOME BETWEEN
THIS LOW AND THE DEPARTING HIGH WITH BREEZY SOUTHWEST WINDS AT
TIMES...MAINLY ACROSS THE NORTHERN CWA. SHOULD BE A FAIR AMOUNT OF
SUNSHINE TO START BUT INCREASING MID/HIGH CLOUDS THIS AFTERNOON
INTO THIS EVENING. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE
ACROSS THE AREA TONIGHT WITH LIMITED FORCING/MOISTURE. BETTER
CHANCES FOR SHOWERS OR SPRINKLES WILL LIKELY REMAIN BOTH NORTH AND
SOUTH OF THE CWA AND REMOVED MENTIONABLE POPS.

AS COLDER AIR SPREADS ACROSS THE REGION MONDAY AFTERNOON INTO
MONDAY NIGHT...LAKE EFFECT RAIN SHOWERS ARE EXPECTED TO DEVELOP
OVER SOUTHERN LAKE MICHIGAN AND AFFECT MAINLY NORTHWEST INDIANA
BUT AS HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES TUESDAY...
ITS POSSIBLE WINDS MAY TURN ENOUGH TO THE NORTHEAST FOR A FEW RAIN
SHOWERS TO REACH EASTERN COOK COUNTY TUESDAY MORNING...BEFORE THE
PRECIP DISSIPATES AS THE HIGH BUILDS SOUTHEAST ACROSS THE REGION.

THIS HIGH WILL MAINTAIN DRY AND QUIET WEATHER WEDNESDAY AND
THURSDAY WITH ANOTHER WAVE MOVING ACROSS THE PLAINS THURSDAY AND
POSSIBLY REACHING THE AREA THURSDAY NIGHT OR FRIDAY BUT MODELS
WEAKEN THIS CONSIDERABLY SHOWING NO PRECIP REACHING THE CWA. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 16Z...

* GUSTY SW WINDS THIS AFTERNOON.
* MVFR CIGS THIS AFTERNOON

KMD

//DISCUSSION...UPDATED 16Z...

MVFR CIGS EXPANDING TO THE SOUTH AND WEST...BUT THEY HAVE MADE IT
INTO KRPJ AND KDKB. NAM AND RAP MODELS SUGGEST AT LEAST A PERIOD
OF SCATTERED MVFR CLOUDS...POSSIBLY BROKEN THIS AFTERNOON. WILL
TAKE A CLOSE LOOK AT THIS FOR THE 18Z TAF CYCLE.

KMD

PREVIOUS DISCUSSION FROM 12Z FOLLOWS...

PATCHY GROUND FOG IN RURAL AREAS WILL QUICKLY DISSIPATE EARLY THIS
MORNING WITH SOUTHWEST WINDS DEVELOPING AND GRADUALLY INCREASING.
WILL LIKELY BE SOME AT LEAST SPORIDIC GUSTINESS THIS
AFTERNOON...THOUGH INCREASING CLOUD COVER COULD LIMIT THE DURATION
AND INTENSITY OF THE GUSTS SOME. WINDS AROUND 2000FT AGL INCREASE
TO 35-40KT FOR A TIME THIS EVENING...THOUGH EXPECT ENOUGH MIXING
IN THE LOW LEVEL AND STRONG ENOUGH SFC WINDS TO PRECLUDE A BIG
LLWS PROBLEM. FRONT WILL SHIFT WINDS TO THE NORTHWEST MONDAY
MORNING BUT LITTLE THREAT OF ANY PRECIP EXISTS WITH THE FRONTAL
PASSAGE. OTHER THAN THIS MORNING`S RURAL GROUND FOG LOOK FOR VFR
CONDITIONS THROUGH THE TAF CYCLE.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE WIND TRENDS
* LOW-MEDIUM CONFIDENCE IN MVFR REMAINING SCATTERED AT ORD/MDW

IZZI

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191456
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
956 AM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 654 AM CDT SUN OCT 19 2014

Aside from some patchy MVFR/IFR conditions early this morning,
predominantly VFR conditions are expected across the central
Illinois terminals through the 12Z TAF valid time. Light/variable
winds to start the day will increase in speed and shift to the
southwest as a ridge of high pressure pushes east of the area. A
disturbance will move across the area late tonight. While a light
shower can`t be ruled out, the chances are too low to include in
the TAFS at this time.


&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak






000
FXUS63 KILX 191456
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
956 AM CDT Sun Oct 19 2014

.UPDATE...
ISSUED AT 956 AM CDT SUN OCT 19 2014

Persistent area of clouds that failed to completely clear out of
central Illinois last night remains in place across parts of the
area this morning. 1430z visible satellite imagery shows cloud
cover along/east of a Peoria to Springfield line. These low clouds
are beginning to advance to the E/NE as S/SW winds develop on the
back-side of departing high pressure. As winds increase, the
forward speed of the clouds will as well, so am expecting them to
depart the CWA into Indiana by early afternoon. After that, mostly
sunny skies with only a few high/thin cirrus clouds can be
anticipated for the balance of the day. Due to the sunshine and
southwesterly winds, afternoon high temperatures will be quite a
bit warmer than previous days, with readings reaching the upper
50s and lower 60s. Made some adjustments to hourly sky grids to
better time the expected clearing and tweaked hourly temps.
Forecast update has already been issued.

&&

.SHORT TERM...(Today)
ISSUED AT 305 AM CDT SUN OCT 19 2014

Pesky low clouds continue to linger across the southern 2/3 or so of
the forecast area early this morning. This fact is holding surface
temperatures and dew points up considerably, and mitigating the
frost threat. However, temperatures have fallen to frosty level
across northern portion of the forecast area where skies have
cleared. HRRR and RAP models both suggest clouds should linger for
at least a few more hours across much of the southern CWA, something
that is hard to argue with looking at recent satellite trends. So,
plan to drop Frost Advisory from the southern half of the forecast
area.

Otherwise, quiet weather is on tap for the forecast area today, with
weak short wave ridging drifting overhead, and the associated
surface ridge pushing off to the east. Low level return flow on the
back side of the surface ridge will help push temperatures back into
the 60s today across much of the forecast area. However, the tricky
cloud cover forecast would likely impact how warm we ultimately get.
While most of the synoptic models suggest a mostly sunny day can be
expected, the high resolution HRRR & RAP, suggest at least the first
half of the day may trend closer to mostly cloudy. The high res
models have a better handle on what is occurring at the moment, so
I`m reluctant to disregard their solutions.

&&

.LONG TERM...(Tonight through Saturday)
ISSUED AT 305 AM CDT SUN OCT 19 2014

A fast moving wave currently across North Dakota is expected to drop
into the Great Lakes on Monday. The main low will stay well to our
northeast, with the trailing cold front sweeping through the
forecast area through early Monday afternoon. The threat of showers
with this feature is mainly across the southeast half of the
forecast area late evening through the overnight hours, with the GFS
and ECMWF both in decent agreement, while the NAM persists with a
dry forecast. Soundings do not show much moisture, so any showers
that occur will be fairly light. Have lingered some 30% PoP`s in the
far southeast CWA into early Monday morning, although have limited
this to areas south of I-70.

Otherwise, largely quiet week on tap for the area, as skinny ridge
builds toward the Mississippi Valley mid week with development of a
large cutoff low over the eastern states. As the eastern low slowly
drifts east late week, a deep shortwave across the Plains will
eventually split with a piece of energy forming a secondary cutoff
low over the lower Mississippi Valley. As this occurs, the threat of
rain east of the river will evaporate quickly Thursday evening with
the moisture being drawn toward this southern low.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 654 AM CDT SUN OCT 19 2014

Aside from some patchy MVFR/IFR conditions early this morning,
predominantly VFR conditions are expected across the central
Illinois terminals through the 12Z TAF valid time. Light/variable
winds to start the day will increase in speed and shift to the
southwest as a ridge of high pressure pushes east of the area. A
disturbance will move across the area late tonight. While a light
shower can`t be ruled out, the chances are too low to include in
the TAFS at this time.


&&

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

$$

UPDATE...Barnes
SHORT TERM...Bak
LONG TERM...Geelhart
AVIATION...Bak







000
FXUS63 KLOT 191442
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
942 AM CDT SUN OCT 19 2014

.DISCUSSION...

320 AM...FAIRLY QUIET WEATHER EXPECTED THROUGH THE END OF THE WEEK
WITH A CHANCE OF A SHOWER OR SPRINKLES TONIGHT AND THEN LAKE
EFFECT RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.

LOWER CLOUDS HAVE CLEARED ALL BUT FAR EASTERN CWA...AND WILL BE
CLEARING THERE BEFORE SUNRISE. WITH CALM WINDS AS HIGH PRESSURE
MOVES SOUTHEAST ACROSS THE AREA...TEMPS HAVE DROPPED INTO THE
LOWER TO MID 30S MOST AREAS AND THE FROST ADVISORY AND ITS TIMING
IS ON TRACK. SOME PATCHY/SHALLOW GROUND FOG HAS DEVELOPED AND NOT
EXPECTING THIS TO BECOME WIDESPREAD.

LOW PRESSURE WILL MOVE SOUTHEAST FROM MANITOBA TODAY REACHING THE
NORTHERN LAKES TONIGHT. THE GRADIENT WILL TIGHTEN SOME BETWEEN
THIS LOW AND THE DEPARTING HIGH WITH BREEZY SOUTHWEST WINDS AT
TIMES...MAINLY ACROSS THE NORTHERN CWA. SHOULD BE A FAIR AMOUNT OF
SUNSHINE TO START BUT INCREASING MID/HIGH CLOUDS THIS AFTERNOON
INTO THIS EVENING. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE
ACROSS THE AREA TONIGHT WITH LIMITED FORCING/MOISTURE. BETTER
CHANCES FOR SHOWERS OR SPRINKLES WILL LIKELY REMAIN BOTH NORTH AND
SOUTH OF THE CWA AND REMOVED MENTIONABLE POPS.

AS COLDER AIR SPREADS ACROSS THE REGION MONDAY AFTERNOON INTO
MONDAY NIGHT...LAKE EFFECT RAIN SHOWERS ARE EXPECTED TO DEVELOP
OVER SOUTHERN LAKE MICHIGAN AND AFFECT MAINLY NORTHWEST INDIANA
BUT AS HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES TUESDAY...
ITS POSSIBLE WINDS MAY TURN ENOUGH TO THE NORTHEAST FOR A FEW RAIN
SHOWERS TO REACH EASTERN COOK COUNTY TUESDAY MORNING...BEFORE THE
PRECIP DISSIPATES AS THE HIGH BUILDS SOUTHEAST ACROSS THE REGION.

THIS HIGH WILL MAINTAIN DRY AND QUIET WEATHER WEDNESDAY AND
THURSDAY WITH ANOTHER WAVE MOVING ACROSS THE PLAINS THURSDAY AND
POSSIBLY REACHING THE AREA THURSDAY NIGHT OR FRIDAY BUT MODELS
WEAKEN THIS CONSIDERABLY SHOWING NO PRECIP REACHING THE CWA. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* GUSTY SW WINDS THIS AFTERNOON.

KMD

//DISCUSSION...UPDATED 12Z...

PATCHY GROUND FOG IN RURAL AREAS WILL QUICKLY DISSIPATE EARLY THIS
MORNING WITH SOUTHWEST WINDS DEVELOPING AND GRADUALLY INCREASING.
WILL LIKELY BE SOME AT LEAST SPORIDIC GUSTINESS THIS
AFTERNOON...THOUGH INCREASING CLOUD COVER COULD LIMIT THE DURATION
AND INTENSITY OF THE GUSTS SOME. WINDS AROUND 2000FT AGL INCREASE
TO 35-40KT FOR A TIME THIS EVENING...THOUGH EXPECT ENOUGH MIXING
IN THE LOW LEVEL AND STRONG ENOUGH SFC WINDS TO PRECLUDE A BIG
LLWS PROBLEM. FRONT WILL SHIFT WINDS TO THE NORTHWEST MONDAY
MORNING BUT LITTLE THREAT OF ANY PRECIP EXISTS WITH THE FRONTAL
PASSAGE. OTHER THAN THIS MORNING`S RURAL GROUND FOG LOOK FOR VFR
CONDITIONS THROUGH THE TAF CYCLE.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS

IZZI

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
     ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
     ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 10 AM SUNDAY.

IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 10 AM
     SUNDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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 191442
AFDLOT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
942 AM CDT SUN OCT 19 2014

.DISCUSSION...

320 AM...FAIRLY QUIET WEATHER EXPECTED THROUGH THE END OF THE WEEK
WITH A CHANCE OF A SHOWER OR SPRINKLES TONIGHT AND THEN LAKE
EFFECT RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.

LOWER CLOUDS HAVE CLEARED ALL BUT FAR EASTERN CWA...AND WILL BE
CLEARING THERE BEFORE SUNRISE. WITH CALM WINDS AS HIGH PRESSURE
MOVES SOUTHEAST ACROSS THE AREA...TEMPS HAVE DROPPED INTO THE
LOWER TO MID 30S MOST AREAS AND THE FROST ADVISORY AND ITS TIMING
IS ON TRACK. SOME PATCHY/SHALLOW GROUND FOG HAS DEVELOPED AND NOT
EXPECTING THIS TO BECOME WIDESPREAD.

LOW PRESSURE WILL MOVE SOUTHEAST FROM MANITOBA TODAY REACHING THE
NORTHERN LAKES TONIGHT. THE GRADIENT WILL TIGHTEN SOME BETWEEN
THIS LOW AND THE DEPARTING HIGH WITH BREEZY SOUTHWEST WINDS AT
TIMES...MAINLY ACROSS THE NORTHERN CWA. SHOULD BE A FAIR AMOUNT OF
SUNSHINE TO START BUT INCREASING MID/HIGH CLOUDS THIS AFTERNOON
INTO THIS EVENING. A TRAILING COLD FRONT FROM THIS LOW WILL MOVE
ACROSS THE AREA TONIGHT WITH LIMITED FORCING/MOISTURE. BETTER
CHANCES FOR SHOWERS OR SPRINKLES WILL LIKELY REMAIN BOTH NORTH AND
SOUTH OF THE CWA AND REMOVED MENTIONABLE POPS.

AS COLDER AIR SPREADS ACROSS THE REGION MONDAY AFTERNOON INTO
MONDAY NIGHT...LAKE EFFECT RAIN SHOWERS ARE EXPECTED TO DEVELOP
OVER SOUTHERN LAKE MICHIGAN AND AFFECT MAINLY NORTHWEST INDIANA
BUT AS HIGH PRESSURE BUILDS ACROSS THE WESTERN LAKES TUESDAY...
ITS POSSIBLE WINDS MAY TURN ENOUGH TO THE NORTHEAST FOR A FEW RAIN
SHOWERS TO REACH EASTERN COOK COUNTY TUESDAY MORNING...BEFORE THE
PRECIP DISSIPATES AS THE HIGH BUILDS SOUTHEAST ACROSS THE REGION.

THIS HIGH WILL MAINTAIN DRY AND QUIET WEATHER WEDNESDAY AND
THURSDAY WITH ANOTHER WAVE MOVING ACROSS THE PLAINS THURSDAY AND
POSSIBLY REACHING THE AREA THURSDAY NIGHT OR FRIDAY BUT MODELS
WEAKEN THIS CONSIDERABLY SHOWING NO PRECIP REACHING THE CWA. CMS

&&

.AVIATION...

//ORD AND MDW CONCERNS...UPDATED 14Z...

* GUSTY SW WINDS THIS AFTERNOON.

KMD

//DISCUSSION...UPDATED 12Z...

PATCHY GROUND FOG IN RURAL AREAS WILL QUICKLY DISSIPATE EARLY THIS
MORNING WITH SOUTHWEST WINDS DEVELOPING AND GRADUALLY INCREASING.
WILL LIKELY BE SOME AT LEAST SPORIDIC GUSTINESS THIS
AFTERNOON...THOUGH INCREASING CLOUD COVER COULD LIMIT THE DURATION
AND INTENSITY OF THE GUSTS SOME. WINDS AROUND 2000FT AGL INCREASE
TO 35-40KT FOR A TIME THIS EVENING...THOUGH EXPECT ENOUGH MIXING
IN THE LOW LEVEL AND STRONG ENOUGH SFC WINDS TO PRECLUDE A BIG
LLWS PROBLEM. FRONT WILL SHIFT WINDS TO THE NORTHWEST MONDAY
MORNING BUT LITTLE THREAT OF ANY PRECIP EXISTS WITH THE FRONTAL
PASSAGE. OTHER THAN THIS MORNING`S RURAL GROUND FOG LOOK FOR VFR
CONDITIONS THROUGH THE TAF CYCLE.

IZZI

//ORD AND MDW CONFIDENCE...UPDATED 12Z...

* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS

IZZI

//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...

MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE.

WEDNESDAY THROUGH SATURDAY...VFR.

IZZI

&&

.MARINE...
209 AM CDT

A FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST INTO THE GREAT
LAKES REGION TONIGHT. SOUTHWEST WINDS WILL BEGIN TO RAMP UP TODAY IN
ADVANCE OF THIS SYSTEM WITH A PERIOD OF NEAR GALE FORCE SOUTHWEST
WINDS EXPECTED OVER NORTHERN PORTIONS OF THE LAKE THIS AFTERNOON
TRANSLATING SOUTH TO SOUTHERN LAKE MICHIGAN THIS EVENING. THE
DURATION OF GALE FORCE GUSTS THIS AFTERNOON INTO THIS EVENING LOOKS
TO BE SHORT IN MOST LOCATIONS WITH A DURATION PROBABLY ONLY A
COUPLE-FEW HOURS. GIVEN THE SHORT DURATION AND MARGINAL SET-UP HAVE
OPTED TO HOLD OFF ON GALE HEADLINES AND JUST INCLUDE A FEW GUSTS TO
GALES IN THE GLF/GRIDS. A PERIOD OF FRESH NORTHERLY WINDS IS
EXPECTED LATE MONDAY THOUGH TUESDAY AS LOW MOVES MORE SLOWLY
EASTWARD AND HIGH PRESSURE BUILDS IN FROM THE NORTH. BY MIDWEEK
WINDS/WAVES SHOULD SUBSIDE ON THE LAKE WITH FAIRLY LIGHT WINDS
EXPECTED THE REMAINDER OF THE WEEK.

IZZI

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
     ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
     ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 10 AM SUNDAY.

IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 10 AM
     SUNDAY.

LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
     LMZ745...7 PM SUNDAY TO 3 AM MONDAY.

&&

$$

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






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