000
FXUS63 KIWX 241743
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
143 PM EDT FRI MAY 24 2013

.SYNOPSIS...
ISSUED AT 140 PM EDT THU MAY 23 2013

HIGH PRESSURE WILL CONTINUE TO BUILD SOUTHEAST FROM CANADA ACROSS
THE GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT... CAUSING FAIR
WEATHER ACROSS THE REGION... WITH UNSEASONABLY COOL TEMPERATURES.

&&

.UPDATE...
ISSUED AT 119 PM EDT FRI MAY 24 2013

HAVE LOWERED HIGHS FOR ALL LOCATIONS WITH DEPTH OF CAA ACROSS THE
AREA WINNING OUT OVER STRONG LATE MAY SUNSHINE. LAKE BREEZE WAS
WORKING INLAND AND WILL BRING TEMPS TO A HALT ALONG AND BEHIND.
SKIES GENERALLY CLEAR ACROSS MOST AREAS WITH EXCEPTION OF SOME
POCKETS OF CU WITH THE LAKE BREEZE AND FURTHER SE.



&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM EDT FRI MAY 24 2013

COOL HIGH PRESSURE OVER THE UPR GRTLKS WILL MOVE VERY SLOWLY E-SE
THROUGH THIS PERIOD AS LOW PRESSURE CLOSES OFF AND DEEPENS ALONG THE
NEW ENGLAND COAST. EXTENSIVE POST FRONTAL STRATO CU DECK WAS MOVG
SLOWLY SOUTH BUT STILL LINGERING OVER SE 1/2 OF THE CWA AT 07Z
WITH SOME NEW DEVELOPMENT OVER NW INDIANA AND SE MI DOWNWIND OF
LAKE HURON. EXPECT SOME CLOUD COVER WILL LINGER OVER MAINLY SE
PORTION OF CWA PAST DAWN... BUT SUBSIDENCE/DRYING SHOULD CONT
DIMINISHING CLOUD COVER TREND WITH SUNNY SKIES MOST OF THE DAY.
COMBINATION OF LOW LEVEL THERMAL TROF MOVG EAST OF THE CWA TODAY
ALONG WITH NEARLY FULL SUNSHINE SHOULD RESULT IN A DECENT WARMUP.
LITTLE CHANGE MADE TO PREVIOUS FCST WITH HIGHS STILL EXPECTED TO
EXCEED CONSENSUS MOS BY A FEW DEGREES.

SHRTWV LIFTING NE INTO THE NRN PLAINS TODAY/TNGT SHOULD RESULT IN
SOME TSTMS DEVELOPING AT NOSE OF LLJ WHICH WILL ADVECT E-SE TOWARD
THE GRTLKS/OH VALLEY. CONVECTION NOT EXPECTED TO REACH OUR
AREA... BUT SOME CIRRUS FROM THE UPSTREAM CONVECTION WILL LIKELY
OVERSPREAD THE CWA TONIGHT. THIS SHOULD LIMIT TEMPERATURE DROP IN
OUR CWA DESPITE A DRY AIRMASS AND LIGHT WINDS. LEANED TOWARD
WARMER GUIDANCE WITH LOWS FCST WELL BLO NORMAL IN THE U30S/L40S.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM EDT FRI MAY 24 2013

TRANQUIL WEATHER EXPECTED FOR THE BULK OF THIS FORECAST PERIOD AS
EXPANSIVE LONGWAVE RIDGE BUILDS OVER THE GREAT LAKES. PRECIP CHANCES
WILL DEPEND ON RATHER VEXING SMALL-SCALE VORTICITY MAXIMA ROTATING
THROUGH THE EASTERN EDGE OF THIS RIDGE OVER THE WEEKEND AND THE
EVENTUAL PASSAGE OF A LOW LEVEL WARM FRONT EARLY NEXT WEEK. LATEST
00Z NCEP MODELS CONTINUE TO BE AWFULLY BULLISH IN THE EASTWARD PUSH
OF LOW LEVEL THETA-E ADVECTION COMPARED TO THEIR EC AND GEM
COUNTERPARTS. NAM AND GFS SEEM TO BE SUFFERING FROM CONVECTIVE
FEEDBACK ISSUES ASSOCIATED WITH THUNDERSTORMS FIRING ON THE NOSE OF
A 35KT LLJ OVER THE CENTRAL PLAINS. THE DOWNSTREAM PROPAGATION OF
THESE CONVECTIVELY INDUCED WAVES IS GENERATING POCKETS OF QPF FOR
OUR CWA SATURDAY AND SUNDAY. REMAIN VERY SKEPTICAL OF THIS IDEA AND
STILL PREFER THE DRIER ECMWF/GEM SOLUTION. STEERING LAYER FLOW LOOKS
TO KEEP CONVECTION SOUTHWEST OF OUR CWA AND STRENGTH OF RIDGING
ALOFT COMBINED WITH OVERALL BLOCKY NATURE OF HEMISPHERIC PATTERN
FAVORS A SLOWER EASTWARD PROGRESSION OF THE LOW LEVEL BAROCLINIC
ZONE. WARM FRONT WILL EVENTUALLY MAKE ITS WAY EAST BUT SHOWERS
SHOULD HOLD OFF UNTIL AT LEAST MONDAY. BY THAT POINT...PACIFIC JET
ENERGY SHOULD FORCE SOME EASTERN PROGRESSION OF STUBBORN CENTRAL
CONUS RIDGE WHILE PIECES OF THE WESTERN CONUS TROUGH EJECT NORTHEAST
AND ATTEMPT TO DAMPEN THE RIDGE SOMEWHAT. CURRENT THINKING IS
TUESDAY WILL BE THE BEST CHANCE FOR PRECIP BUT WILL LIKELY BE FAIRLY
SCATTERED GIVEN LACK OF ANY GOOD UPPER LEVEL SUPPORT. MIDLEVEL RIDGE
LOOKS TO EXPAND AGAIN BY MIDWEEK WITH SOUTHERN GREAT LAKES IN A
STRONGLY CAPPED AND DRY WARM SECTOR.

AS FOR TEMPERATURES...LACK OF ANY STRONG THERMAL ADVECTIONS WILL
LEAD TO TEMPS ON SAT AND SUN THAT ARE VERY SIMILAR TO THOSE EXPECTED
TODAY. INCREASING CLOUDS WILL LIKELY OFFSET THE GRADUAL MODERATION
OF AMBIENT AIRMASS AND HIGHS IN THE MID TO UPPER 60S STILL LOOK GOOD
BASED ON LATEST GUIDANCE. INCREASINGLY LIMITED RADIATIVE LOSSES WILL
RESULT IN OVERNIGHT LOWS A TOUCH WARMER...GENERALLY MID TO UPPER
40S. MONDAY WILL BE A BIT OF A TRANSITIONAL DAY BEFORE WARM FRONT
LIFTS NORTHEAST ON TUESDAY. GOOD SOUTHWEST FLOW/WAA AND DRY
SUBSIDENT AIRMASS SHOULD ALLOW FOR TEMPS WELL INTO THE 80S BY
MIDWEEK. CONTINUED EARLIER NOTED TREND OF UPWARD ADJUSTMENT TO
CONSENSUS BLENDS BASED ON 850MB TEMPS APPROACHING THE UPPER TEENS
ONCE AGAIN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 119 PM EDT FRI MAY 24 2013

GENERALLY CLEAR SKIES PREVAIL AT BOTH TAF SITES...WITH TREND
EXPECTED TO CONTINUE THROUGH THE PERIOD. LAKE BREEZE HAS WORKED
WELL INLAND AND CLOUD BAND ASSOCIATED WITH THIS WERE PASSING OVER
KSBN AT THIS TIME. DEPARTURE OF BAND WAS ALREADY UNDERWAY SO WILL
NOT ADD TO TAFS GIVEN COVERAGE/TIMING AND CLOUD HGT ABOVE 3000 FT. WINDS
WILL DIMINISH OVERNIGHT AND REMAIN ON THE LIGHTER SIDE ON
SATURDAY. NOT OVERLY IMPRESSED WITH CIRRUS SETUP FOR TONIGHT
PREVIOUSLY INHERITED. WILL PUSH BACK TIMING OF THE CLOUDS TO
CLOSER TO MIDNIGHT AS CONVECTION FIRES TO THE NW AND CIRRUS SHIELD DRIFTS
THIS WAY LATER.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT UNTIL 7 PM CDT THIS EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

UPDATE...FISHER
SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...AGD
AVIATION...FISHER


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 241053
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
653 AM EDT FRI MAY 24 2013

.SYNOPSIS...
ISSUED AT 322 AM EDT THU MAY 23 2013

HIGH PRESSURE WILL CONTINUE TO BUILD SOUTHEAST FROM CANADA ACROSS
THE GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT... CAUSING FAIR
WEATHER ACROSS THE REGION... WITH UNSEASONABLY COOL TEMPERATURES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM EDT FRI MAY 24 2013

COOL HIGH PRESSURE OVER THE UPR GRTLKS WILL MOVE VERY SLOWLY E-SE
THROUGH THIS PERIOD AS LOW PRESSURE CLOSES OFF AND DEEPENS ALONG THE
NEW ENGLAND COAST. EXTENSIVE POST FRONTAL STRATO CU DECK WAS MOVG
SLOWLY SOUTH BUT STILL LINGERING OVER SE 1/2 OF THE CWA AT 07Z
WITH SOME NEW DEVELOPMENT OVER NW INDIANA AND SE MI DOWNWIND OF
LAKE HURON. EXPECT SOME CLOUD COVER WILL LINGER OVER MAINLY SE
PORTION OF CWA PAST DAWN... BUT SUBSIDENCE/DRYING SHOULD CONT
DIMINISHING CLOUD COVER TREND WITH SUNNY SKIES MOST OF THE DAY.
COMBINATION OF LOW LEVEL THERMAL TROF MOVG EAST OF THE CWA TODAY
ALONG WITH NEARLY FULL SUNSHINE SHOULD RESULT IN A DECENT WARMUP.
LITTLE CHANGE MADE TO PREVIOUS FCST WITH HIGHS STILL EXPECTED TO
EXCEED CONSENSUS MOS BY A FEW DEGREES.

SHRTWV LIFTING NE INTO THE NRN PLAINS TODAY/TNGT SHOULD RESULT IN
SOME TSTMS DEVELOPING AT NOSE OF LLJ WHICH WILL ADVECT E-SE TOWARD
THE GRTLKS/OH VALLEY. CONVECTION NOT EXPECTED TO REACH OUR
AREA... BUT SOME CIRRUS FROM THE UPSTREAM CONVECTION WILL LIKELY
OVERSPREAD THE CWA TONIGHT. THIS SHOULD LIMIT TEMPERATURE DROP IN
OUR CWA DESPITE A DRY AIRMASS AND LIGHT WINDS. LEANED TOWARD
WARMER GUIDANCE WITH LOWS FCST WELL BLO NORMAL IN THE U30S/L40S.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM EDT FRI MAY 24 2013

TRANQUIL WEATHER EXPECTED FOR THE BULK OF THIS FORECAST PERIOD AS
EXPANSIVE LONGWAVE RIDGE BUILDS OVER THE GREAT LAKES. PRECIP CHANCES
WILL DEPEND ON RATHER VEXING SMALL-SCALE VORTICITY MAXIMA ROTATING
THROUGH THE EASTERN EDGE OF THIS RIDGE OVER THE WEEKEND AND THE
EVENTUAL PASSAGE OF A LOW LEVEL WARM FRONT EARLY NEXT WEEK. LATEST
00Z NCEP MODELS CONTINUE TO BE AWFULLY BULLISH IN THE EASTWARD PUSH
OF LOW LEVEL THETA-E ADVECTION COMPARED TO THEIR EC AND GEM
COUNTERPARTS. NAM AND GFS SEEM TO BE SUFFERING FROM CONVECTIVE
FEEDBACK ISSUES ASSOCIATED WITH THUNDERSTORMS FIRING ON THE NOSE OF
A 35KT LLJ OVER THE CENTRAL PLAINS. THE DOWNSTREAM PROPAGATION OF
THESE CONVECTIVELY INDUCED WAVES IS GENERATING POCKETS OF QPF FOR
OUR CWA SATURDAY AND SUNDAY. REMAIN VERY SKEPTICAL OF THIS IDEA AND
STILL PREFER THE DRIER ECMWF/GEM SOLUTION. STEERING LAYER FLOW LOOKS
TO KEEP CONVECTION SOUTHWEST OF OUR CWA AND STRENGTH OF RIDGING
ALOFT COMBINED WITH OVERALL BLOCKY NATURE OF HEMISPHERIC PATTERN
FAVORS A SLOWER EASTWARD PROGRESSION OF THE LOW LEVEL BAROCLINIC
ZONE. WARM FRONT WILL EVENTUALLY MAKE ITS WAY EAST BUT SHOWERS
SHOULD HOLD OFF UNTIL AT LEAST MONDAY. BY THAT POINT...PACIFIC JET
ENERGY SHOULD FORCE SOME EASTERN PROGRESSION OF STUBBORN CENTRAL
CONUS RIDGE WHILE PIECES OF THE WESTERN CONUS TROUGH EJECT NORTHEAST
AND ATTEMPT TO DAMPEN THE RIDGE SOMEWHAT. CURRENT THINKING IS
TUESDAY WILL BE THE BEST CHANCE FOR PRECIP BUT WILL LIKELY BE FAIRLY
SCATTERED GIVEN LACK OF ANY GOOD UPPER LEVEL SUPPORT. MIDLEVEL RIDGE
LOOKS TO EXPAND AGAIN BY MIDWEEK WITH SOUTHERN GREAT LAKES IN A
STRONGLY CAPPED AND DRY WARM SECTOR.

AS FOR TEMPERATURES...LACK OF ANY STRONG THERMAL ADVECTIONS WILL
LEAD TO TEMPS ON SAT AND SUN THAT ARE VERY SIMILAR TO THOSE EXPECTED
TODAY. INCREASING CLOUDS WILL LIKELY OFFSET THE GRADUAL MODERATION
OF AMBIENT AIRMASS AND HIGHS IN THE MID TO UPPER 60S STILL LOOK GOOD
BASED ON LATEST GUIDANCE. INCREASINGLY LIMITED RADIATIVE LOSSES WILL
RESULT IN OVERNIGHT LOWS A TOUCH WARMER...GENERALLY MID TO UPPER
40S. MONDAY WILL BE A BIT OF A TRANSITIONAL DAY BEFORE WARM FRONT
LIFTS NORTHEAST ON TUESDAY. GOOD SOUTHWEST FLOW/WAA AND DRY
SUBSIDENT AIRMASS SHOULD ALLOW FOR TEMPS WELL INTO THE 80S BY
MIDWEEK. CONTINUED EARLIER NOTED TREND OF UPWARD ADJUSTMENT TO
CONSENSUS BLENDS BASED ON 850MB TEMPS APPROACHING THE UPPER TEENS
ONCE AGAIN.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 649 AM EDT FRI MAY 24 2013

BACK EDGE OF POST FRONTAL STRATO CU MOVG THROUGH FWA EARLY THIS
MORNING WITH JUST PATCHY LOW CLOUDS UPSTREAM. LOW LEVELS WILL
CONTINUE TO DRY OUT TODAY AS HIGH PRESSURE BUILDS IN... SO LITTLE
IF ANY DIURNAL CU EXPECTED. CIRRUS OVER THE NRN PLAINS/ROCKIES
WILL MOVE SE IN NW FLOW ALOFT AND PRBLY BE ENHANCED TONIGHT BY
CONVECTIVE DEVELOPMENT AT THE NOSE OF THE LLJ OVER THE
NRN PLAINS/UPR MIDWEST... THESE HIGH CLOUDS SHOULD OVERSPREAD NRN
INDIANA TONIGHT. LIGHT NORTHERLY WINDS EXPECTED ACROSS NRN
INDIANA TODAY AS RIDGE AXIS REMAINS WEST OF THE AREA. WINDS SHOULD
BECOME NEARLY CALM TONIGHT AS THE HIGH PRESSURE CENTER MOVES
SLOWLY THROUGH THE AREA.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...AGD
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 240736
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
336 AM EDT FRI MAY 24 2013

.SYNOPSIS...
ISSUED AT 322 AM EDT THU MAY 23 2013

HIGH PRESSURE WILL CONTINUE TO BUILD SOUTHEAST FROM CANADA ACROSS
THE GREAT LAKES AND OHIO VALLEY TODAY AND TONIGHT... CAUSING FAIR
WEATHER ACROSS THE REGION... WITH UNSEASONABLY COOL TEMPERATURES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM EDT FRI MAY 24 2013

COOL HIGH PRESSURE OVER THE UPR GRTLKS WILL MOVE VERY SLOWLY E-SE
THROUGH THIS PERIOD AS LOW PRESSURE CLOSES OFF AND DEEPENS ALONG THE
NEW ENGLAND COAST. EXTENSIVE POST FRONTAL STRATO CU DECK WAS MOVG
SLOWLY SOUTH BUT STILL LINGERING OVER SE 1/2 OF THE CWA AT 07Z
WITH SOME NEW DEVELOPMENT OVER NW INDIANA AND SE MI DOWNWIND OF
LAKE HURON. EXPECT SOME CLOUD COVER WILL LINGER OVER MAINLY SE
PORTION OF CWA PAST DAWN... BUT SUBSIDENCE/DRYING SHOULD CONT
DIMINISHING CLOUD COVER TREND WITH SUNNY SKIES MOST OF THE DAY.
COMBINATION OF LOW LEVEL THERMAL TROF MOVG EAST OF THE CWA TODAY
ALONG WITH NEARLY FULL SUNSHINE SHOULD RESULT IN A DECENT WARMUP.
LITTLE CHANGE MADE TO PREVIOUS FCST WITH HIGHS STILL EXPECTED TO
EXCEED CONSENSUS MOS BY A FEW DEGREES.

SHRTWV LIFTING NE INTO THE NRN PLAINS TODAY/TNGT SHOULD RESULT IN
SOME TSTMS DEVELOPING AT NOSE OF LLJ WHICH WILL ADVECT E-SE TOWARD
THE GRTLKS/OH VALLEY. CONVECTION NOT EXPECTED TO REACH OUR
AREA... BUT SOME CIRRUS FROM THE UPSTREAM CONVECTION WILL LIKELY
OVERSPREAD THE CWA TONIGHT. THIS SHOULD LIMIT TEMPERATURE DROP IN
OUR CWA DESPITE A DRY AIRMASS AND LIGHT WINDS. LEANED TOWARD
WARMER GUIDANCE WITH LOWS FCST WELL BLO NORMAL IN THE U30S/L40S.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 322 AM EDT FRI MAY 24 2013

TRANQUIL WEATHER EXPECTED FOR THE BULK OF THIS FORECAST PERIOD AS
EXPANSIVE LONGWAVE RIDGE BUILDS OVER THE GREAT LAKES. PRECIP CHANCES
WILL DEPEND ON RATHER VEXING SMALL-SCALE VORTICITY MAXIMA ROTATING
THROUGH THE EASTERN EDGE OF THIS RIDGE OVER THE WEEKEND AND THE
EVENTUAL PASSAGE OF A LOW LEVEL WARM FRONT EARLY NEXT WEEK. LATEST
00Z NCEP MODELS CONTINUE TO BE AWFULLY BULLISH IN THE EASTWARD PUSH
OF LOW LEVEL THETA-E ADVECTION COMPARED TO THEIR EC AND GEM
COUNTERPARTS. NAM AND GFS SEEM TO BE SUFFERING FROM CONVECTIVE
FEEDBACK ISSUES ASSOCIATED WITH THUNDERSTORMS FIRING ON THE NOSE OF
A 35KT LLJ OVER THE CENTRAL PLAINS. THE DOWNSTREAM PROPAGATION OF
THESE CONVECTIVELY INDUCED WAVES IS GENERATING POCKETS OF QPF FOR
OUR CWA SATURDAY AND SUNDAY. REMAIN VERY SKEPTICAL OF THIS IDEA AND
STILL PREFER THE DRIER ECMWF/GEM SOLUTION. STEERING LAYER FLOW LOOKS
TO KEEP CONVECTION SOUTHWEST OF OUR CWA AND STRENGTH OF RIDGING
ALOFT COMBINED WITH OVERALL BLOCKY NATURE OF HEMISPHERIC PATTERN
FAVORS A SLOWER EASTWARD PROGRESSION OF THE LOW LEVEL BAROCLINIC
ZONE. WARM FRONT WILL EVENTUALLY MAKE ITS WAY EAST BUT SHOWERS
SHOULD HOLD OFF UNTIL AT LEAST MONDAY. BY THAT POINT...PACIFIC JET
ENERGY SHOULD FORCE SOME EASTERN PROGRESSION OF STUBBORN CENTRAL
CONUS RIDGE WHILE PIECES OF THE WESTERN CONUS TROUGH EJECT NORTHEAST
AND ATTEMPT TO DAMPEN THE RIDGE SOMEWHAT. CURRENT THINKING IS
TUESDAY WILL BE THE BEST CHANCE FOR PRECIP BUT WILL LIKELY BE FAIRLY
SCATTERED GIVEN LACK OF ANY GOOD UPPER LEVEL SUPPORT. MIDLEVEL RIDGE
LOOKS TO EXPAND AGAIN BY MIDWEEK WITH SOUTHERN GREAT LAKES IN A
STRONGLY CAPPED AND DRY WARM SECTOR.

AS FOR TEMPERATURES...LACK OF ANY STRONG THERMAL ADVECTIONS WILL
LEAD TO TEMPS ON SAT AND SUN THAT ARE VERY SIMILAR TO THOSE EXPECTED
TODAY. INCREASING CLOUDS WILL LIKELY OFFSET THE GRADUAL MODERATION
OF AMBIENT AIRMASS AND HIGHS IN THE MID TO UPPER 60S STILL LOOK GOOD
BASED ON LATEST GUIDANCE. INCREASINGLY LIMITED RADIATIVE LOSSES WILL
RESULT IN OVERNIGHT LOWS A TOUCH WARMER...GENERALLY MID TO UPPER
40S. MONDAY WILL BE A BIT OF A TRANSITIONAL DAY BEFORE WARM FRONT
LIFTS NORTHEAST ON TUESDAY. GOOD SOUTHWEST FLOW/WAA AND DRY
SUBSIDENT AIRMASS SHOULD ALLOW FOR TEMPS WELL INTO THE 80S BY
MIDWEEK. CONTINUED EARLIER NOTED TREND OF UPWARD ADJUSTMENT TO
CONSENSUS BLENDS BASED ON 850MB TEMPS APPROACHING THE UPPER TEENS
ONCE AGAIN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 109 AM EDT FRI MAY 24 2013

BACK EDGE OF POST FRONTAL STRATO CU APCHG NERN INDIANA ATTM. THUS
EXPECT MVFR CONDITIONS AT FWA TO PERSIST A FEW MORE HOURS WHILE
SBN REMAINS ON EDGE OF THE DECK WITH PREDOMINANTLY SCT LOW CLOUDS
THROUGH DAWN. HIGH PRESSURE AND ASSOCIATED DRY AIRMASS MOVG INTO
THE AREA SHOULD RESULT IN VFR CONDITIONS WITH MOSTLY CLEAR SKIES
AND LIGHT NORTH WINDS TODAY. WINDS WILL BECOME CALM TONIGHT WITH
HIGH PRESSURE MOVG THROUGH THE AREA. VFR CONDITIONS WILL CONT
TONIGHT WITH INCREASING CIRRUS FROM THE W-NW EXPECTED OVERNIGHT AS
BLOWOFF FROM WAA TSTMS OVER THE NRN PLAINS/UPR MIDWEST IS ADVECTED
INTO OUR AREA VIA NW FLOW ALOFT.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...AGD
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 240520
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
120 AM EDT FRI MAY 24 2013

.SYNOPSIS...
ISSUED AT 443 PM EDT THU MAY 23 2013

HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
TONIGHT... AND REMAIN OVER THE AREA THROUGH THE WEEKEND. THIS
WILL BRING BELOW NORMAL TEMPERATURES AND GENERALLY CLEAR SKIES
OVER THE NEXT FEW DAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

SURFACE COLD FRONT MOVED THROUGH THE FORECAST AREA
THIS MORNING WHICH BROUGHT A ROUND OF LIGHT RAIN THROUGH MOST OF THE
AREA. RAIN SHOWERS AND DRIZZLE HAVE CONTINUED DREARY CONDITIONS
THROUGH THE DAY DUE TO CVA AHEAD OF A S/W TROUGH DIGGING INTO THE
LOWER GREAT LAKES. THESE CONDITIONS WERE EXACERBATED IN OUR
NORTHWESTERN AREAS WHERE AN EXTENSIVE MARINE LAYER HAS ADVECTED AS
FAR INLAND AS ELKHART AND KOSCIUSKO COUNTIES WITH DRIZZLE AND SUB
1KFT CEILINGS OBSERVED. CONDITIONS WILL QUICKLY IMPROVE ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS SUBSIDENCE BEHIND THE SHARP
TROUGH AXIS...EVIDENT ON WATER VAPOR CROSSING LAKE MICHIGAN
NOW...USHERS IN MOSTLY CLEAR SKIES OVERNIGHT.

THESE MOSTLY CLEAR SKIES TONIGHT WILL ALLOW TEMPERATURES TO DROP
INTO THE UPPER 30S. HAVE LITTLE CONCERN ABOUT FROST GIVEN SURFACE
WINDS BETWEEN 6 AND 8 KTS OVERNIGHT IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM.

HIGH PRESSURE WILL KEEP SKIES SUNNY ON FRIDAY WHICH WILL HELP
TEMPERATURES RECOVER FOR A NEAR 25 DEGREE DIURNAL SWING. COLD AIR
ADVECTION WILL CEASE NEAR 12Z AND SOME 850MB WARMING WILL OCCUR IN
OUR WESTERN AREAS AS SUBSIDENCE INCREASES WITH THE APPROACHING
RIDGE. MOST MODEL GUIDANCE FOR TOMORROW IS LOWER THAN CURRENT
FORECAST HIGH TEMPERATURES...BUT ELECTED TO MAKE ONLY MINOR
ADJUSTMENTS TO PREVIOUS FORECAST HIGH TEMPERATURES GIVEN
AFOREMENTIONED FULL SUN AND BUILDING RIDGE.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

QUIET WEATHER TO BEGIN THIS PERIOD AS LOW LEVEL RIDGE AXIS EXTENDS
FROM WESTERN GREAT LAKES INTO THE MID MS RIVER VALLEY. MAIN FORECAST
CHALLENGE FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BE RESOLVING
AMPLITUDE OF MID/UPPER LEVEL RIDGING AND THE POSSIBILITY OF EMBEDDED
CONVECTIVELY ENHANCED VORTICITY MAXIMUM PROGRESSING THROUGH THE MEAN
RIDGE. A GREATER CHANCE OF CONVECTION FOR THE SATURDAY/SUNDAY PERIOD
SHOULD REMAIN TO THE WEST OF THE AREA ACROSS THE MID MS RIVER VALLEY
IN BETTER COLOCATION WITH LOW LEVEL MASS CONVERGENCE ASSOCIATED WITH
LOW LEVEL JET. THICKNESS ORIENTATION/PROPAGATION VECTORS MAY SUPPORT
EAST/SOUTHEAST TRACK OF THIS CONVECTION INTO FAR WEST OR SOUTHWEST
PORTIONS OF THE FORECAST AREA IN THE SATURDAY NIGHT-MONDAY PERIOD.
WILL CONTINUE TO PLAY IT CONSERVATIVELY WITH THIS FORECAST WITH MORE
CREDENCE INTO GEM/EC IDEA OF SLOWER EASTWARD PROGRESSION OF LOW
LEVEL THETAE RIDGE AND SLOWER NORTHWARD WARM FRONTAL PUSH. SOME
CONCERN THAT GFS IS OVERDOING CONVECTIVELY ENHANCED VORTICES GIVEN
RECENT BIASES AND SOMEWHAT OVERDONE LOW LEVEL MOISTURE. THUS...WILL
MAINTAIN JUST SOME SLIGHT CHANCE POPS ACROSS THE FAR WEST/SOUTHWEST
DURING THIS PERIOD. WITH LOCAL AREA IN INFLECTION ZONE OF UPPER
LEVEL PATTERN...LOW LEVEL THERMAL ADVECTIONS WILL REMAIN WEAK
THROUGH THE WEEKEND WITH ONLY A SLOW MODERATING TEMPERATURE TREND
INTO THE LOWER 70S BY MONDAY.

MORE AGGRESSIVE WARM FRONTAL PUSH STILL EXPECTED LATE MONDAY INTO
TUESDAY WITH EC PREFERENCE...AND HIGHS TO AROUND 80 POSSIBLE ONCE
AGAIN BY TUESDAY AFTERNOON. MAINTAINED PREVIOUS CHANCE TSRA POPS FOR
TUESDAY/TUESDAY NIGHT AS WARM FRONT LIFTS NORTH THROUGH THE
AREA...WITH FOCUS FOR ADDITIONAL TSRA CHANCES LIKELY SHIFTING NORTH
OF THE AREA TOWARD MIDWEEK AS CAPPING ISSUES ARISE IN WARM SECTOR.
HAVE KEPT WED/THU DRY AT THIS TIME...ALTHOUGH DEPENDING ON WARM
FRONTAL PROGRESSION MAY EVENTUALLY NEED TO ADD A CHANCE ACROSS THE
NORTH. MEDIUM RANGE MODELS IN GENERAL AGREEMENT ON UPPER RIDGE
AMPLIFICATION TOWARD THE END OF THE PERIOD DOWNSTREAM OF NEXT
AMPLIFIED WESTERN CONUS TROUGH. DID NUDGE CR ALLBLEND HIGHS UP A BIT
FOR WED/THU INTO THE LOWER TO MID 80S. SOUTH/SOUTHWEST NEAR SFC FLOW
TRAJECTORIES SHOULD LIMIT LAKE COOLING TO NORTHERN PORTIONS OF
BERRIEN COUNTY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 109 AM EDT FRI MAY 24 2013

BACK EDGE OF POST FRONTAL STRATO CU APCHG NERN INDIANA ATTM. THUS
EXPECT MVFR CONDITIONS AT FWA TO PERSIST A FEW MORE HOURS WHILE
SBN REMAINS ON EDGE OF THE DECK WITH PREDOMINANTLY SCT LOW CLOUDS
THROUGH DAWN. HIGH PRESSURE AND ASSOCIATED DRY AIRMASS MOVG INTO
THE AREA SHOULD RESULT IN VFR CONDITIONS WITH MOSTLY CLEAR SKIES
AND LIGHT NORTH WINDS TODAY. WINDS WILL BECOME CALM TONIGHT WITH
HIGH PRESSURE MOVG THROUGH THE AREA. VFR CONDITIONS WILL CONT
TONIGHT WITH INCREASING CIRRUS FROM THE W-NW EXPECTED OVERNIGHT AS
BLOWOFF FROM WAA TSTMS OVER THE NRN PLAINS/UPR MIDWEST IS ADVECTED
INTO OUR AREA VIA NW FLOW ALOFT.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR LMZ043-
     046.

&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...MARSILI
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 232352
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
752 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 443 PM EDT THU MAY 23 2013

HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST
TONIGHT... AND REMAIN OVER THE AREA THROUGH THE WEEKEND. THIS
WILL BRING BELOW NORMAL TEMPERATURES AND GENERALLY CLEAR SKIES
OVER THE NEXT FEW DAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

SURFACE COLD FRONT MOVED THROUGH THE FORECAST AREA
THIS MORNING WHICH BROUGHT A ROUND OF LIGHT RAIN THROUGH MOST OF THE
AREA. RAIN SHOWERS AND DRIZZLE HAVE CONTINUED DREARY CONDITIONS
THROUGH THE DAY DUE TO CVA AHEAD OF A S/W TROUGH DIGGING INTO THE
LOWER GREAT LAKES. THESE CONDITIONS WERE EXACERBATED IN OUR
NORTHWESTERN AREAS WHERE AN EXTENSIVE MARINE LAYER HAS ADVECTED AS
FAR INLAND AS ELKHART AND KOSCIUSKO COUNTIES WITH DRIZZLE AND SUB
1KFT CEILINGS OBSERVED. CONDITIONS WILL QUICKLY IMPROVE ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS SUBSIDENCE BEHIND THE SHARP
TROUGH AXIS...EVIDENT ON WATER VAPOR CROSSING LAKE MICHIGAN
NOW...USHERS IN MOSTLY CLEAR SKIES OVERNIGHT.

THESE MOSTLY CLEAR SKIES TONIGHT WILL ALLOW TEMPERATURES TO DROP
INTO THE UPPER 30S. HAVE LITTLE CONCERN ABOUT FROST GIVEN SURFACE
WINDS BETWEEN 6 AND 8 KTS OVERNIGHT IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM.

HIGH PRESSURE WILL KEEP SKIES SUNNY ON FRIDAY WHICH WILL HELP
TEMPERATURES RECOVER FOR A NEAR 25 DEGREE DIURNAL SWING. COLD AIR
ADVECTION WILL CEASE NEAR 12Z AND SOME 850MB WARMING WILL OCCUR IN
OUR WESTERN AREAS AS SUBSIDENCE INCREASES WITH THE APPROACHING
RIDGE. MOST MODEL GUIDANCE FOR TOMORROW IS LOWER THAN CURRENT
FORECAST HIGH TEMPERATURES...BUT ELECTED TO MAKE ONLY MINOR
ADJUSTMENTS TO PREVIOUS FORECAST HIGH TEMPERATURES GIVEN
AFOREMENTIONED FULL SUN AND BUILDING RIDGE.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

QUIET WEATHER TO BEGIN THIS PERIOD AS LOW LEVEL RIDGE AXIS EXTENDS
FROM WESTERN GREAT LAKES INTO THE MID MS RIVER VALLEY. MAIN FORECAST
CHALLENGE FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BE RESOLVING
AMPLITUDE OF MID/UPPER LEVEL RIDGING AND THE POSSIBILITY OF EMBEDDED
CONVECTIVELY ENHANCED VORTICITY MAXIMUM PROGRESSING THROUGH THE MEAN
RIDGE. A GREATER CHANCE OF CONVECTION FOR THE SATURDAY/SUNDAY PERIOD
SHOULD REMAIN TO THE WEST OF THE AREA ACROSS THE MID MS RIVER VALLEY
IN BETTER COLOCATION WITH LOW LEVEL MASS CONVERGENCE ASSOCIATED WITH
LOW LEVEL JET. THICKNESS ORIENTATION/PROPAGATION VECTORS MAY SUPPORT
EAST/SOUTHEAST TRACK OF THIS CONVECTION INTO FAR WEST OR SOUTHWEST
PORTIONS OF THE FORECAST AREA IN THE SATURDAY NIGHT-MONDAY PERIOD.
WILL CONTINUE TO PLAY IT CONSERVATIVELY WITH THIS FORECAST WITH MORE
CREDENCE INTO GEM/EC IDEA OF SLOWER EASTWARD PROGRESSION OF LOW
LEVEL THETAE RIDGE AND SLOWER NORTHWARD WARM FRONTAL PUSH. SOME
CONCERN THAT GFS IS OVERDOING CONVECTIVELY ENHANCED VORTICES GIVEN
RECENT BIASES AND SOMEWHAT OVERDONE LOW LEVEL MOISTURE. THUS...WILL
MAINTAIN JUST SOME SLIGHT CHANCE POPS ACROSS THE FAR WEST/SOUTHWEST
DURING THIS PERIOD. WITH LOCAL AREA IN INFLECTION ZONE OF UPPER
LEVEL PATTERN...LOW LEVEL THERMAL ADVECTIONS WILL REMAIN WEAK
THROUGH THE WEEKEND WITH ONLY A SLOW MODERATING TEMPERATURE TREND
INTO THE LOWER 70S BY MONDAY.

MORE AGGRESSIVE WARM FRONTAL PUSH STILL EXPECTED LATE MONDAY INTO
TUESDAY WITH EC PREFERENCE...AND HIGHS TO AROUND 80 POSSIBLE ONCE
AGAIN BY TUESDAY AFTERNOON. MAINTAINED PREVIOUS CHANCE TSRA POPS FOR
TUESDAY/TUESDAY NIGHT AS WARM FRONT LIFTS NORTH THROUGH THE
AREA...WITH FOCUS FOR ADDITIONAL TSRA CHANCES LIKELY SHIFTING NORTH
OF THE AREA TOWARD MIDWEEK AS CAPPING ISSUES ARISE IN WARM SECTOR.
HAVE KEPT WED/THU DRY AT THIS TIME...ALTHOUGH DEPENDING ON WARM
FRONTAL PROGRESSION MAY EVENTUALLY NEED TO ADD A CHANCE ACROSS THE
NORTH. MEDIUM RANGE MODELS IN GENERAL AGREEMENT ON UPPER RIDGE
AMPLIFICATION TOWARD THE END OF THE PERIOD DOWNSTREAM OF NEXT
AMPLIFIED WESTERN CONUS TROUGH. DID NUDGE CR ALLBLEND HIGHS UP A BIT
FOR WED/THU INTO THE LOWER TO MID 80S. SOUTH/SOUTHWEST NEAR SFC FLOW
TRAJECTORIES SHOULD LIMIT LAKE COOLING TO NORTHERN PORTIONS OF
BERRIEN COUNTY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 751 PM EDT THU MAY 23 2013

SLIGHT DELAY IN SCOUR OF STRATOCU DECK ACROSS NORTHERN INDIANA
PER CONTINUED INFLUENCE OF SLIGHT 925MB CYCLONIC FLOW AMID
SATURATED 900-850MB LAYER WITHIN SUBSIDENCE INVERSION. A FEW HOURS
OF FUEL ALTERNATE CONDITIONS AT KSBN THEN TRANSITION TO HIGH END
MVFR...IN LINE WITH KFWA EXPECTED DOMINANT TREND WHERE A DEEPER
MIXED LAYER/LACK OF DOMINANT MARINE LAYER HAS HELPED TO MAINTAIN
BETTER FLIGHT CONDS THROUGH THE DAY. WITH TIME...GRADUAL
TRANSITION TO ANTICYCLONIC LOW LEVEL FLOW AS UPSTREAM SURFACE HIGH
CENTROID NEAR MN ARROWHEAD CONTS TO DROP SEWD INTO YOOP ALONG WITH
PERSISTENT SUBSIDENT/DRY AIR ADVECTION TO ASSUREDLY YIELD
SUBSTANTIAL CLEARING ACROSS NORTHERN IN BY ABOUT 04 UTC.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...MARSILI
AVIATION...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 232045
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
445 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 443 PM EDT THU MAY 23 2013

HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST TONIGHT...AND
REMAIN OVER THE AREA THROUGH THE WEEKEND. THIS WILL BRING BELOW
NORMAL TEMPERATURES AND GENERALLY CLEAR SKIES OVER THE NEXT FEW
DAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

SURFACE COLD FRONT MOVED THROUGH THE FORECAST AREA
THIS MORNING WHICH BROUGHT A ROUND OF LIGHT RAIN THROUGH MOST OF THE
AREA. RAIN SHOWERS AND DRIZZLE HAVE CONTINUED DREARY CONDITIONS
THROUGH THE DAY DUE TO CVA AHEAD OF A S/W TROUGH DIGGING INTO THE
LOWER GREAT LAKES. THESE CONDITIONS WERE EXACERBATED IN OUR
NORTHWESTERN AREAS WHERE AN EXTENSIVE MARINE LAYER HAS ADVECTED AS
FAR INLAND AS ELKHART AND KOSCIUSKO COUNTIES WITH DRIZZLE AND SUB
1KFT CEILINGS OBSERVED. CONDITIONS WILL QUICKLY IMPROVE ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS SUBSIDENCE BEHIND THE SHARP
TROUGH AXIS...EVIDENT ON WATER VAPOR CROSSING LAKE MICHIGAN
NOW...USHERS IN MOSTLY CLEAR SKIES OVERNIGHT.

THESE MOSTLY CLEAR SKIES TONIGHT WILL ALLOW TEMPERATURES TO DROP
INTO THE UPPER 30S. HAVE LITTLE CONCERN ABOUT FROST GIVEN SURFACE
WINDS BETWEEN 6 AND 8 KTS OVERNIGHT IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM.

HIGH PRESSURE WILL KEEP SKIES SUNNY ON FRIDAY WHICH WILL HELP
TEMPERATURES RECOVER FOR A NEAR 25 DEGREE DIURNAL SWING. COLD AIR
ADVECTION WILL CEASE NEAR 12Z AND SOME 850MB WARMING WILL OCCUR IN
OUR WESTERN AREAS AS SUBSIDENCE INCREASES WITH THE APPROACHING
RIDGE. MOST MODEL GUIDANCE FOR TOMORROW IS LOWER THAN CURRENT
FORECAST HIGH TEMPERATURES...BUT ELECTED TO MAKE ONLY MINOR
ADJUSTMENTS TO PREVIOUS FORECAST HIGH TEMPERATURES GIVEN
AFOREMENTIONED FULL SUN AND BUILDING RIDGE.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

QUIET WEATHER TO BEGIN THIS PERIOD AS LOW LEVEL RIDGE AXIS EXTENDS
FROM WESTERN GREAT LAKES INTO THE MID MS RIVER VALLEY. MAIN FORECAST
CHALLENGE FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BE RESOLVING
AMPLITUDE OF MID/UPPER LEVEL RIDGING AND THE POSSIBILITY OF EMBEDDED
CONVECTIVELY ENHANCED VORTICITY MAXIMUM PROGRESSING THROUGH THE MEAN
RIDGE. A GREATER CHANCE OF CONVECTION FOR THE SATURDAY/SUNDAY PERIOD
SHOULD REMAIN TO THE WEST OF THE AREA ACROSS THE MID MS RIVER VALLEY
IN BETTER COLOCATION WITH LOW LEVEL MASS CONVERGENCE ASSOCIATED WITH
LOW LEVEL JET. THICKNESS ORIENTATION/PROPAGATION VECTORS MAY SUPPORT
EAST/SOUTHEAST TRACK OF THIS CONVECTION INTO FAR WEST OR SOUTHWEST
PORTIONS OF THE FORECAST AREA IN THE SATURDAY NIGHT-MONDAY PERIOD.
WILL CONTINUE TO PLAY IT CONSERVATIVELY WITH THIS FORECAST WITH MORE
CREDENCE INTO GEM/EC IDEA OF SLOWER EASTWARD PROGRESSION OF LOW
LEVEL THETAE RIDGE AND SLOWER NORTHWARD WARM FRONTAL PUSH. SOME
CONCERN THAT GFS IS OVERDOING CONVECTIVELY ENHANCED VORTICES GIVEN
RECENT BIASES AND SOMEWHAT OVERDONE LOW LEVEL MOISTURE. THUS...WILL
MAINTAIN JUST SOME SLIGHT CHANCE POPS ACROSS THE FAR WEST/SOUTHWEST
DURING THIS PERIOD. WITH LOCAL AREA IN INFLECTION ZONE OF UPPER
LEVEL PATTERN...LOW LEVEL THERMAL ADVECTIONS WILL REMAIN WEAK
THROUGH THE WEEKEND WITH ONLY A SLOW MODERATING TEMPERATURE TREND
INTO THE LOWER 70S BY MONDAY.

MORE AGGRESSIVE WARM FRONTAL PUSH STILL EXPECTED LATE MONDAY INTO
TUESDAY WITH EC PREFERENCE...AND HIGHS TO AROUND 80 POSSIBLE ONCE
AGAIN BY TUESDAY AFTERNOON. MAINTAINED PREVIOUS CHANCE TSRA POPS FOR
TUESDAY/TUESDAY NIGHT AS WARM FRONT LIFTS NORTH THROUGH THE
AREA...WITH FOCUS FOR ADDITIONAL TSRA CHANCES LIKELY SHIFTING NORTH
OF THE AREA TOWARD MIDWEEK AS CAPPING ISSUES ARISE IN WARM SECTOR.
HAVE KEPT WED/THU DRY AT THIS TIME...ALTHOUGH DEPENDING ON WARM
FRONTAL PROGRESSION MAY EVENTUALLY NEED TO ADD A CHANCE ACROSS THE
NORTH. MEDIUM RANGE MODELS IN GENERAL AGREEMENT ON UPPER RIDGE
AMPLIFICATION TOWARD THE END OF THE PERIOD DOWNSTREAM OF NEXT
AMPLIFIED WESTERN CONUS TROUGH. DID NUDGE CR ALLBLEND HIGHS UP A BIT
FOR WED/THU INTO THE LOWER TO MID 80S. SOUTH/SOUTHWEST NEAR SFC FLOW
TRAJECTORIES SHOULD LIMIT LAKE COOLING TO NORTHERN PORTIONS OF
BERRIEN COUNTY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU MAY 23 2013

IFR CONDITIONS AT SOUTH BEND EXPECTED TO CONTINUE FOR A
COUPLE MORE HOURS BEFORE SUBSIDENCE BEHIND THE APPROACHING SHORTWAVE
IMPROVES FLYING CONDITIONS TO MVFR AND EVENTUALLY VFR. KFWA SHOULD
REMAIN MVFR AS LOWER CIGS HAVE STAYED EAST OF THE TERMINAL THUS FAR.
THERE IS A SMALL CHANCE FOR IFR CIGS TO MOVE INTO THE TERMINAL OVER
THE NEXT FEW HOURS...BUT GIVEN LOW CONFIDENCE...HAVE ELECTED TO OMIT
ANY MENTION IN THE TAF.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...KG
SHORT TERM...BENTLEY
LONG TERM...MARSILI
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 232002
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
402 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 121 PM EDT THU MAY 23 2013

RAIN CHANCES WILL CONTINUE THROUGH THURSDAY AFTERNOON AS A COLD
FRONT PUSHES SOUTH OF THE AREA. HIGH PRESSURE WILL BUILD INTO THE
AREA FROM THE NORTHWEST THURSDAY EVENING...WHICH WILL BRING MAINLY
DRY CONDITIONS AND BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

SURFACE COLD FRONT MOVED THROUGH THE FORECAST AREA
THIS MORNING WHICH BROUGHT A ROUND OF LIGHT RAIN THROUGH MOST OF THE
AREA. RAIN SHOWERS AND DRIZZLE HAVE CONTINUED DREARY CONDITIONS
THROUGH THE DAY DUE TO CVA AHEAD OF A S/W TROUGH DIGGING INTO THE
LOWER GREAT LAKES. THESE CONDITIONS WERE EXACERBATED IN OUR
NORTHWESTERN AREAS WHERE AN EXTENSIVE MARINE LAYER HAS ADVECTED AS
FAR INLAND AS ELKHART AND KOSCIUSKO COUNTIES WITH DRIZZLE AND SUB
1KFT CEILINGS OBSERVED. CONDITIONS WILL QUICKLY IMPROVE ACROSS THE
AREA FROM NORTHWEST TO SOUTHEAST AS SUBSIDENCE BEHIND THE SHARP
TROUGH AXIS...EVIDENT ON WATER VAPOR CROSSING LAKE MICHIGAN
NOW...USHERS IN MOSTLY CLEAR SKIES OVERNIGHT.

THESE MOSTLY CLEAR SKIES TONIGHT WILL ALLOW TEMPERATURES TO DROP
INTO THE UPPER 30S. HAVE LITTLE CONCERN ABOUT FROST GIVEN SURFACE
WINDS BETWEEN 6 AND 8 KTS OVERNIGHT IN THE WAKE OF THE DEPARTING LOW
PRESSURE SYSTEM.

HIGH PRESSURE WILL KEEP SKIES SUNNY ON FRIDAY WHICH WILL HELP
TEMPERATURES RECOVER FOR A NEAR 25 DEGREE DIURNAL SWING. COLD AIR
ADVECTION WILL CEASE NEAR 12Z AND SOME 850MB WARMING WILL OCCUR IN
OUR WESTERN AREAS AS SUBSIDENCE INCREASES WITH THE APPROACHING
RIDGE. MOST MODEL GUIDANCE FOR TOMORROW IS LOWER THAN CURRENT
FORECAST HIGH TEMPERATURES...BUT ELECTED TO MAKE ONLY MINOR
ADJUSTMENTS TO PREVIOUS FORECAST HIGH TEMPERATURES GIVEN
AFOREMENTIONED FULL SUN AND BUILDING RIDGE.

&&

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 PM EDT THU MAY 23 2013

QUIET WEATHER TO BEGIN THIS PERIOD AS LOW LEVEL RIDGE AXIS EXTENDS
FROM WESTERN GREAT LAKES INTO THE MID MS RIVER VALLEY. MAIN FORECAST
CHALLENGE FOR THE WEEKEND INTO EARLY NEXT WEEK WILL BE RESOLVING
AMPLITUDE OF MID/UPPER LEVEL RIDGING AND THE POSSIBILITY OF EMBEDDED
CONVECTIVELY ENHANCED VORTICITY MAXIMUM PROGRESSING THROUGH THE MEAN
RIDGE. A GREATER CHANCE OF CONVECTION FOR THE SATURDAY/SUNDAY PERIOD
SHOULD REMAIN TO THE WEST OF THE AREA ACROSS THE MID MS RIVER VALLEY
IN BETTER COLOCATION WITH LOW LEVEL MASS CONVERGENCE ASSOCIATED WITH
LOW LEVEL JET. THICKNESS ORIENTATION/PROPAGATION VECTORS MAY SUPPORT
EAST/SOUTHEAST TRACK OF THIS CONVECTION INTO FAR WEST OR SOUTHWEST
PORTIONS OF THE FORECAST AREA IN THE SATURDAY NIGHT-MONDAY PERIOD.
WILL CONTINUE TO PLAY IT CONSERVATIVELY WITH THIS FORECAST WITH MORE
CREDENCE INTO GEM/EC IDEA OF SLOWER EASTWARD PROGRESSION OF LOW
LEVEL THETAE RIDGE AND SLOWER NORTHWARD WARM FRONTAL PUSH. SOME
CONCERN THAT GFS IS OVERDOING CONVECTIVELY ENHANCED VORTICES GIVEN
RECENT BIASES AND SOMEWHAT OVERDONE LOW LEVEL MOISTURE. THUS...WILL
MAINTAIN JUST SOME SLIGHT CHANCE POPS ACROSS THE FAR WEST/SOUTHWEST
DURING THIS PERIOD. WITH LOCAL AREA IN INFLECTION ZONE OF UPPER
LEVEL PATTERN...LOW LEVEL THERMAL ADVECTIONS WILL REMAIN WEAK
THROUGH THE WEEKEND WITH ONLY A SLOW MODERATING TEMPERATURE TREND
INTO THE LOWER 70S BY MONDAY.

MORE AGGRESSIVE WARM FRONTAL PUSH STILL EXPECTED LATE MONDAY INTO
TUESDAY WITH EC PREFERENCE...AND HIGHS TO AROUND 80 POSSIBLE ONCE
AGAIN BY TUESDAY AFTERNOON. MAINTAINED PREVIOUS CHANCE TSRA POPS FOR
TUESDAY/TUESDAY NIGHT AS WARM FRONT LIFTS NORTH THROUGH THE
AREA...WITH FOCUS FOR ADDITIONAL TSRA CHANCES LIKELY SHIFTING NORTH
OF THE AREA TOWARD MIDWEEK AS CAPPING ISSUES ARISE IN WARM SECTOR.
HAVE KEPT WED/THU DRY AT THIS TIME...ALTHOUGH DEPENDING ON WARM
FRONTAL PROGRESSION MAY EVENTUALLY NEED TO ADD A CHANCE ACROSS THE
NORTH. MEDIUM RANGE MODELS IN GENERAL AGREEMENT ON UPPER RIDGE
AMPLIFICATION TOWARD THE END OF THE PERIOD DOWNSTREAM OF NEXT
AMPLIFIED WESTERN CONUS TROUGH. DID NUDGE CR ALLBLEND HIGHS UP A BIT
FOR WED/THU INTO THE LOWER TO MID 80S. SOUTH/SOUTHWEST NEAR SFC FLOW
TRAJECTORIES SHOULD LIMIT LAKE COOLING TO NORTHERN PORTIONS OF
BERRIEN COUNTY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU MAY 23 2013

IFR CONDITIONS AT SOUTH BEND EXPECTED TO CONTINUE FOR A
COUPLE MORE HOURS BEFORE SUBSIDENCE BEHIND THE APPROACHING SHORTWAVE
IMPROVES FLYING CONDITIONS TO MVFR AND EVENTUALLY VFR. KFWA SHOULD
REMAIN MVFR AS LOWER CIGS HAVE STAYED EAST OF THE TERMINAL THUS FAR.
THERE IS A SMALL CHANCE FOR IFR CIGS TO MOVE INTO THE TERMINAL OVER
THE NEXT FEW HOURS...BUT GIVEN LOW CONFIDENCE...HAVE ELECTED TO OMIT
ANY MENTION IN THE TAF.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...NG
SHORT TERM...BENTLEY
LONG TERM...MARSILI
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 231734
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
134 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 121 PM EDT THU MAY 23 2013

RAIN CHANCES WILL CONTINUE THROUGH THURSDAY AFTERNOON AS A COLD
FRONT PUSHES SOUTH OF THE AREA. HIGH PRESSURE WILL BUILD INTO THE
AREA FROM THE NORTHWEST THURSDAY EVENING...WHICH WILL BRING MAINLY
DRY CONDITIONS AND BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM EDT THU MAY 23 2013

CUT-OFF UPR LEVEL LOW OVER THE MID MS VALLEY CONTS PROCESS OF
BEING ABSORBED BY TROF DIGGING S-SE ACROSS THE GRTLKS. SFC CDFNT
ASSOCIATED WITH THIS UPR TROF EXTENDED FROM SRN LAKE HURON TO JUST
SOUTH OF LAKE MICHIGAN AND THEN WNW ACROSS NRN IL. AREAS OF FOG
OCRG NEAR FRONT OVER SRN LAKE MICHIGAN AND EXTENDING SLIGHTLY
INLAND. FLOW LIGHT ENOUGH TO KEEP THIS FROM SPREADING VERY FAR
INLAND AND AS WINDS PICK UP...BOUNDARY LAYER MIXING SHOULD ALLOW
VSBYS TO IMPROVE NEAR THE LAKE EARLY THIS MORNING. A FAIRLY
WIDESPREAD AREA OF SHOWERS BEHIND THE FRONT ACROSS NRN IL... WI...
AND NW MI. FORCING RESPONSIBLE FOR THESE SHOWERS MAY WEAKEN SOME
TODAY AS UPR LOW CONTS TO SHEAR OUT... BUT EXPECT DIGGING UPR TROF
AND LIFT ALONG FRONTAL ZONE WILL BE SUFFICIENT TO MAINTAIN POST
FRONTAL SHOWERS MOVG SEWD ACROSS OUR AREA DURING THE DAY. SOME
SHOWERS MAY LINGER OVER SERN PORTION OF THE AREA EARLY THIS EVE
BUT SHOULD BE FOLLOWED BY CLEARING OVERNIGHT AS STRONG
SUBSIDENCE/DRYING OVERSPREADS THE CWA.

RATHER TIGHT PRESSURE GRADIENT BEHIND THE FRONT SHOULD RESULT IN
GUSTS UP TO 30MPH BEHIND THE FRONT TODAY... A LITTLE STRONGER IN
VCNTY OF LAKE MICHIGAN WHERE THERMAL GRADIENT ENHANCED. CONTG WITH
GALE WARNING FOR NSH ZONES AND SINCE BEACH SEASON HAS BEGUN...
ISSUED A BEACH HAZARD STATEMENT FOR THE SURF ZONE.

WITH STRONG CDFNT MOVG ACROSS THE AREA TODAY THERE WILL BE A TIGHT
TEMP GRADIENT WITH HIGHS EXPECTED TO RANGE FROM THE L50S NW TO THE
U60S SE. STRONG CAA TODAY/TONIGHT COMBINED WITH CLEARING SKIES
TONIGHT SHOULD ALLOW TEMPS TO FALL INTO THE U30S NORTH AND L40S
SOUTH. WITH SFC HIGH REMAINING TO THE WEST OF OUR AREA OVERNIGHT...
NORTHERLY GRADIENT EXPECTED TO BE STRONG ENOUGH TO MAINTAIN SOME
LIGHT WIND THROUGHOUT THE NIGHT WHICH SHOULD PREVENT A MORE SGFNT
TEMP DROP AND FROST FROM FORMING.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 407 AM EDT THU MAY 23 2013

REMARKABLY PLACID CONDITIONS TO BEGIN THIS LONG TERM PERIOD AS
BLOCKY HIGH AMPLITUDE WAVE TRAIN SLOWLY PROPAGATES
EASTWARD...LEAVING THE SOUTHERN GREAT LAKES ON SUBSIDENT SIDE OF
IMPRESSIVE MID/UPPER LEVEL RIDGE. 1030MB SURFACE ANTICYCLONE WILL BE
FIRMLY IN PLACE BY FRIDAY...LEADING TO A PLEASANT...ALBEIT SOMEWHAT
COOL...DAY. WILL BE INTERESTING TO SEE HOW WARM WE ACTUALLY GET WITH
THE STRONG LATE MAY SUN ANGLE ACTING ON CHILLY CP AIRMASS. THERMAL
TROUGH WILL BE PUSHING EASTWARD DURING THE DAY AND 850MB TEMPS LOOK
TO RECOVER TO AROUND 5C BY THE AFTERNOON. THIS WOULD USUALLY SUPPORT
HIGHS ONLY IN THE LOW 60S BUT FULL SUN SHOULD ALLOW FOR A GOOD
SUPERADIABATIC RESPONSE AT THE SURFACE...PUSHING HIGHS A FEW DEGREES
WARMER. WENT WITH GENERALLY MID 60S...SAVE FOR THE LAKESHORE AREAS
WHERE LIGHT NORTHERLY WINDS WILL ALLOW FOR DECENT MARINE INFLUENCE.
GOOD RADIATIONAL COOLING EXPECTED FRIDAY NIGHT. SURFACE HIGH WILL BE
DIRECTLY OVERHEAD WITH CALM WINDS AND FULL BOUNDARY LAYER
DECOUPLING. COULD BE SOME INCREASING CIRRUS TOWARD DAYBREAK BUT THE
EFFECT SHOULD BE MINIMAL AND EXPECT LOWS AROUND 40F ONCE AGAIN.
FROST IS NOT LIKELY GIVEN MARGINAL TEMPS AND VERY DRY AIRMASS.

FORECAST BECOMES A BIT MORE MUDDLED HEADING INTO THE HOLIDAY
WEEKEND. SEVERAL WEAK VORTICES ARE EXPECTED TO CASCADE DOWN THE
LONGWAVE RIDGE AND INCITE A DECENT WAA/FGEN RESPONSE TO OUR WEST.
QUESTION WILL BE WHETHER OR NOT THIS FORCING CAN CLIP OUR WESTERN
CWA. GIVEN THE STRENGTH OF CONFLUENCE ALOFT AND PERSISTENCE OF
GENERAL AVA IN SLOWLY PROGRESSING LARGE SCALE PATTERN...EXPECT
PRECIP WILL REMAIN CLOSELY TIED TO LOW LEVEL THETA-E GRADIENT DRAPED
OVER THE MIDWEST. PREPONDERANCE OF DRY AIR AND EFFECT OF COLD LAKES
THIS TIME OF YEAR SHOULD MAINTAIN HIGH PRESSURE AND DRY NORTHEAST
FLOW LOCALLY...AS SEEN IN THE LAST FEW ECMWF RUNS. WOULDNT RULE OUT
A FEW SPRINKLES OVER OUR SOUTHWEST AT TIMES THIS WEEKEND BUT
CONFIDENCE IS MUCH TOO LOW TO INCLUDE IN THE FORECAST. BAROCLINIC
ZONE WILL EVENTUALLY WORK ITS WAY EAST AS PACIFIC JET FORCES
DOWNSTREAM RIDGE TO SHIFT EASTWARD EARLY NEXT WEEK. LARGE
DISAGREEMENT IN LATEST MODELS ON HOW AND WHEN THIS WILL HAPPEN
THOUGH. WILL KEEP WITH PREVIOUS ECWMF PREFERENCE FOR NOW AND HOLD
OFF ON POPS UNTIL MIDWEEK. AFTER ANOTHER COOL DAY ON
SATURDAY...EXPECT A SLOW MODERATING TREND THROUGH EARLY NEXT WEEK AS
RIDGE AXIS PASSES OVERHEAD. TEMPS SHOULD RETURN TO AT OR ABOVE
NORMAL BY TUESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 133 PM EDT THU MAY 23 2013

IFR CONDITIONS AT SOUTH BEND EXPECTED TO CONTINUE FOR A
COUPLE MORE HOURS BEFORE SUBSIDENCE BEHIND THE APPROACHING SHORTWAVE
IMPROVES FLYING CONDITIONS TO MVFR AND EVENTUALLY VFR. KFWA SHOULD
REMAIN MVFR AS LOWER CIGS HAVE STAYED EAST OF THE TERMINAL THUS FAR.
THERE IS A SMALL CHANCE FOR IFR CIGS TO MOVE INTO THE TERMINAL OVER
THE NEXT FEW HOURS...BUT GIVEN LOW CONFIDENCE...HAVE ELECTED TO OMIT
ANY MENTION IN THE TAF.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...NG
SHORT TERM...JT
LONG TERM...AGD
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

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

000
FXUS63 KIWX 231721
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
121 PM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 121 PM EDT THU MAY 23 2013

RAIN CHANCES WILL CONTINUE THROUGH THURSDAY AFTERNOON AS A COLD
FRONT PUSHES SOUTH OF THE AREA. HIGH PRESSURE WILL BUILD INTO THE
AREA FROM THE NORTHWEST THURSDAY EVENING...WHICH WILL BRING MAINLY
DRY CONDITIONS AND BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM EDT THU MAY 23 2013

CUT-OFF UPR LEVEL LOW OVER THE MID MS VALLEY CONTS PROCESS OF
BEING ABSORBED BY TROF DIGGING S-SE ACROSS THE GRTLKS. SFC CDFNT
ASSOCIATED WITH THIS UPR TROF EXTENDED FROM SRN LAKE HURON TO JUST
SOUTH OF LAKE MICHIGAN AND THEN WNW ACROSS NRN IL. AREAS OF FOG
OCRG NEAR FRONT OVER SRN LAKE MICHIGAN AND EXTENDING SLIGHTLY
INLAND. FLOW LIGHT ENOUGH TO KEEP THIS FROM SPREADING VERY FAR
INLAND AND AS WINDS PICK UP...BOUNDARY LAYER MIXING SHOULD ALLOW
VSBYS TO IMPROVE NEAR THE LAKE EARLY THIS MORNING. A FAIRLY
WIDESPREAD AREA OF SHOWERS BEHIND THE FRONT ACROSS NRN IL... WI...
AND NW MI. FORCING RESPONSIBLE FOR THESE SHOWERS MAY WEAKEN SOME
TODAY AS UPR LOW CONTS TO SHEAR OUT... BUT EXPECT DIGGING UPR TROF
AND LIFT ALONG FRONTAL ZONE WILL BE SUFFICIENT TO MAINTAIN POST
FRONTAL SHOWERS MOVG SEWD ACROSS OUR AREA DURING THE DAY. SOME
SHOWERS MAY LINGER OVER SERN PORTION OF THE AREA EARLY THIS EVE
BUT SHOULD BE FOLLOWED BY CLEARING OVERNIGHT AS STRONG
SUBSIDENCE/DRYING OVERSPREADS THE CWA.

RATHER TIGHT PRESSURE GRADIENT BEHIND THE FRONT SHOULD RESULT IN
GUSTS UP TO 30MPH BEHIND THE FRONT TODAY... A LITTLE STRONGER IN
VCNTY OF LAKE MICHIGAN WHERE THERMAL GRADIENT ENHANCED. CONTG WITH
GALE WARNING FOR NSH ZONES AND SINCE BEACH SEASON HAS BEGUN...
ISSUED A BEACH HAZARD STATEMENT FOR THE SURF ZONE.

WITH STRONG CDFNT MOVG ACROSS THE AREA TODAY THERE WILL BE A TIGHT
TEMP GRADIENT WITH HIGHS EXPECTED TO RANGE FROM THE L50S NW TO THE
U60S SE. STRONG CAA TODAY/TONIGHT COMBINED WITH CLEARING SKIES
TONIGHT SHOULD ALLOW TEMPS TO FALL INTO THE U30S NORTH AND L40S
SOUTH. WITH SFC HIGH REMAINING TO THE WEST OF OUR AREA OVERNIGHT...
NORTHERLY GRADIENT EXPECTED TO BE STRONG ENOUGH TO MAINTAIN SOME
LIGHT WIND THROUGHOUT THE NIGHT WHICH SHOULD PREVENT A MORE SGFNT
TEMP DROP AND FROST FROM FORMING.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 407 AM EDT THU MAY 23 2013

REMARKABLY PLACID CONDITIONS TO BEGIN THIS LONG TERM PERIOD AS
BLOCKY HIGH AMPLITUDE WAVE TRAIN SLOWLY PROPAGATES
EASTWARD...LEAVING THE SOUTHERN GREAT LAKES ON SUBSIDENT SIDE OF
IMPRESSIVE MID/UPPER LEVEL RIDGE. 1030MB SURFACE ANTICYCLONE WILL BE
FIRMLY IN PLACE BY FRIDAY...LEADING TO A PLEASANT...ALBEIT SOMEWHAT
COOL...DAY. WILL BE INTERESTING TO SEE HOW WARM WE ACTUALLY GET WITH
THE STRONG LATE MAY SUN ANGLE ACTING ON CHILLY CP AIRMASS. THERMAL
TROUGH WILL BE PUSHING EASTWARD DURING THE DAY AND 850MB TEMPS LOOK
TO RECOVER TO AROUND 5C BY THE AFTERNOON. THIS WOULD USUALLY SUPPORT
HIGHS ONLY IN THE LOW 60S BUT FULL SUN SHOULD ALLOW FOR A GOOD
SUPERADIABATIC RESPONSE AT THE SURFACE...PUSHING HIGHS A FEW DEGREES
WARMER. WENT WITH GENERALLY MID 60S...SAVE FOR THE LAKESHORE AREAS
WHERE LIGHT NORTHERLY WINDS WILL ALLOW FOR DECENT MARINE INFLUENCE.
GOOD RADIATIONAL COOLING EXPECTED FRIDAY NIGHT. SURFACE HIGH WILL BE
DIRECTLY OVERHEAD WITH CALM WINDS AND FULL BOUNDARY LAYER
DECOUPLING. COULD BE SOME INCREASING CIRRUS TOWARD DAYBREAK BUT THE
EFFECT SHOULD BE MINIMAL AND EXPECT LOWS AROUND 40F ONCE AGAIN.
FROST IS NOT LIKELY GIVEN MARGINAL TEMPS AND VERY DRY AIRMASS.

FORECAST BECOMES A BIT MORE MUDDLED HEADING INTO THE HOLIDAY
WEEKEND. SEVERAL WEAK VORTICES ARE EXPECTED TO CASCADE DOWN THE
LONGWAVE RIDGE AND INCITE A DECENT WAA/FGEN RESPONSE TO OUR WEST.
QUESTION WILL BE WHETHER OR NOT THIS FORCING CAN CLIP OUR WESTERN
CWA. GIVEN THE STRENGTH OF CONFLUENCE ALOFT AND PERSISTENCE OF
GENERAL AVA IN SLOWLY PROGRESSING LARGE SCALE PATTERN...EXPECT
PRECIP WILL REMAIN CLOSELY TIED TO LOW LEVEL THETA-E GRADIENT DRAPED
OVER THE MIDWEST. PREPONDERANCE OF DRY AIR AND EFFECT OF COLD LAKES
THIS TIME OF YEAR SHOULD MAINTAIN HIGH PRESSURE AND DRY NORTHEAST
FLOW LOCALLY...AS SEEN IN THE LAST FEW ECMWF RUNS. WOULDNT RULE OUT
A FEW SPRINKLES OVER OUR SOUTHWEST AT TIMES THIS WEEKEND BUT
CONFIDENCE IS MUCH TOO LOW TO INCLUDE IN THE FORECAST. BAROCLINIC
ZONE WILL EVENTUALLY WORK ITS WAY EAST AS PACIFIC JET FORCES
DOWNSTREAM RIDGE TO SHIFT EASTWARD EARLY NEXT WEEK. LARGE
DISAGREEMENT IN LATEST MODELS ON HOW AND WHEN THIS WILL HAPPEN
THOUGH. WILL KEEP WITH PREVIOUS ECWMF PREFERENCE FOR NOW AND HOLD
OFF ON POPS UNTIL MIDWEEK. AFTER ANOTHER COOL DAY ON
SATURDAY...EXPECT A SLOW MODERATING TREND THROUGH EARLY NEXT WEEK AS
RIDGE AXIS PASSES OVERHEAD. TEMPS SHOULD RETURN TO AT OR ABOVE
NORMAL BY TUESDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM EDT THU MAY 23 2013

LAKE ENHANCED PORTION OF CDFNT APPEARS TO HAVE STALLED NEAR
SBN EARLY THIS MORNING RESULTING IN OCNL IFR CONDITIONS VARYING TO
VFR THERE. FRONT WILL RESUME S-SE MOVEMENT ACROSS NRN INDIANA TODAY
AS UPR LEVEL TROF MOVES THROUGH. THUS EXPECT TEMPO IFR WILL
TRANSITION TO PREDOMINANT IFR AT SBN AND MVFR AT FWA BY LATE
MORNING. MVFR CONDITIONS EXPECTED ACROSS THE AREA THIS
AFTN... TRANSITIONING TO VFR AND SKC THIS EVE. -SHRA WITH
CONSIDERABLE COVERAGE CONTG UPSTREAM ATTM SO ADJUSTED TEMPO -SHRA
TO ABOUT A 6HR PERIOD OF PREDOMINANT -SHRA TODAY IN LATEST TAFS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT THROUGH FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...NG
SHORT TERM...JT
LONG TERM...AGD
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

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

000
FXUS63 KIWX 231058
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
658 AM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 407 AM EDT WED MAY 22 2013

A COLD FRONT EXTENDING ACROSS SOUTHERN MICHIGAN AND NORTHERN
ILLINOIS THIS MORNING... WILL MOVE SOUTH TO THE OHIO RIVER VALLEY THIS
EVENING. SHOWERS ARE LIKELY AS THE FRONTAL ZONE MOVES THROUGH THE
AREA. HIGH PRESSURE WILL MOVE SOUTH FROM CENTRAL CANADA INTO THE
GREAT LAKES AND OHIO VALLEY BEHIND THE FRONT TONIGHT... CAUSING
SKIES TO CLEAR AND UNSEASONABLY COOL TEMPERATURES TO OVERSPREAD
THE REGION.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM EDT THU MAY 23 2013

CUT-OFF UPR LEVEL LOW OVER THE MID MS VALLEY CONTS PROCESS OF
BEING ABSORBED BY TROF DIGGING S-SE ACROSS THE GRTLKS. SFC CDFNT
ASSOCIATED WITH THIS UPR TROF EXTENDED FROM SRN LAKE HURON TO JUST
SOUTH OF LAKE MICHIGAN AND THEN WNW ACROSS NRN IL. AREAS OF FOG
OCRG NEAR FRONT OVER SRN LAKE MICHIGAN AND EXTENDING SLIGHTLY
INLAND. FLOW LIGHT ENOUGH TO KEEP THIS FROM SPREADING VERY FAR
INLAND AND AS WINDS PICK UP...BOUNDARY LAYER MIXING SHOULD ALLOW
VSBYS TO IMPROVE NEAR THE LAKE EARLY THIS MORNING. A FAIRLY
WIDESPREAD AREA OF SHOWERS BEHIND THE FRONT ACROSS NRN IL... WI...
AND NW MI. FORCING RESPONSIBLE FOR THESE SHOWERS MAY WEAKEN SOME
TODAY AS UPR LOW CONTS TO SHEAR OUT... BUT EXPECT DIGGING UPR TROF
AND LIFT ALONG FRONTAL ZONE WILL BE SUFFICIENT TO MAINTAIN POST
FRONTAL SHOWERS MOVG SEWD ACROSS OUR AREA DURING THE DAY. SOME
SHOWERS MAY LINGER OVER SERN PORTION OF THE AREA EARLY THIS EVE
BUT SHOULD BE FOLLOWED BY CLEARING OVERNIGHT AS STRONG
SUBSIDENCE/DRYING OVERSPREADS THE CWA.

RATHER TIGHT PRESSURE GRADIENT BEHIND THE FRONT SHOULD RESULT IN
GUSTS UP TO 30MPH BEHIND THE FRONT TODAY... A LITTLE STRONGER IN
VCNTY OF LAKE MICHIGAN WHERE THERMAL GRADIENT ENHANCED. CONTG WITH
GALE WARNING FOR NSH ZONES AND SINCE BEACH SEASON HAS BEGUN...
ISSUED A BEACH HAZARD STATEMENT FOR THE SURF ZONE.

WITH STRONG CDFNT MOVG ACROSS THE AREA TODAY THERE WILL BE A TIGHT
TEMP GRADIENT WITH HIGHS EXPECTED TO RANGE FROM THE L50S NW TO THE
U60S SE. STRONG CAA TODAY/TONIGHT COMBINED WITH CLEARING SKIES
TONIGHT SHOULD ALLOW TEMPS TO FALL INTO THE U30S NORTH AND L40S
SOUTH. WITH SFC HIGH REMAINING TO THE WEST OF OUR AREA OVERNIGHT...
NORTHERLY GRADIENT EXPECTED TO BE STRONG ENOUGH TO MAINTAIN SOME
LIGHT WIND THROUGHOUT THE NIGHT WHICH SHOULD PREVENT A MORE SGFNT
TEMP DROP AND FROST FROM FORMING.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 407 AM EDT THU MAY 23 2013

REMARKABLY PLACID CONDITIONS TO BEGIN THIS LONG TERM PERIOD AS
BLOCKY HIGH AMPLITUDE WAVE TRAIN SLOWLY PROPAGATES
EASTWARD...LEAVING THE SOUTHERN GREAT LAKES ON SUBSIDENT SIDE OF
IMPRESSIVE MID/UPPER LEVEL RIDGE. 1030MB SURFACE ANTICYCLONE WILL BE
FIRMLY IN PLACE BY FRIDAY...LEADING TO A PLEASANT...ALBEIT SOMEWHAT
COOL...DAY. WILL BE INTERESTING TO SEE HOW WARM WE ACTUALLY GET WITH
THE STRONG LATE MAY SUN ANGLE ACTING ON CHILLY CP AIRMASS. THERMAL
TROUGH WILL BE PUSHING EASTWARD DURING THE DAY AND 850MB TEMPS LOOK
TO RECOVER TO AROUND 5C BY THE AFTERNOON. THIS WOULD USUALLY SUPPORT
HIGHS ONLY IN THE LOW 60S BUT FULL SUN SHOULD ALLOW FOR A GOOD
SUPERADIABATIC RESPONSE AT THE SURFACE...PUSHING HIGHS A FEW DEGREES
WARMER. WENT WITH GENERALLY MID 60S...SAVE FOR THE LAKESHORE AREAS
WHERE LIGHT NORTHERLY WINDS WILL ALLOW FOR DECENT MARINE INFLUENCE.
GOOD RADIATIONAL COOLING EXPECTED FRIDAY NIGHT. SURFACE HIGH WILL BE
DIRECTLY OVERHEAD WITH CALM WINDS AND FULL BOUNDARY LAYER
DECOUPLING. COULD BE SOME INCREASING CIRRUS TOWARD DAYBREAK BUT THE
EFFECT SHOULD BE MINIMAL AND EXPECT LOWS AROUND 40F ONCE AGAIN.
FROST IS NOT LIKELY GIVEN MARGINAL TEMPS AND VERY DRY AIRMASS.

FORECAST BECOMES A BIT MORE MUDDLED HEADING INTO THE HOLIDAY
WEEKEND. SEVERAL WEAK VORTICES ARE EXPECTED TO CASCADE DOWN THE
LONGWAVE RIDGE AND INCITE A DECENT WAA/FGEN RESPONSE TO OUR WEST.
QUESTION WILL BE WHETHER OR NOT THIS FORCING CAN CLIP OUR WESTERN
CWA. GIVEN THE STRENGTH OF CONFLUENCE ALOFT AND PERSISTENCE OF
GENERAL AVA IN SLOWLY PROGRESSING LARGE SCALE PATTERN...EXPECT
PRECIP WILL REMAIN CLOSELY TIED TO LOW LEVEL THETA-E GRADIENT DRAPED
OVER THE MIDWEST. PREPONDERANCE OF DRY AIR AND EFFECT OF COLD LAKES
THIS TIME OF YEAR SHOULD MAINTAIN HIGH PRESSURE AND DRY NORTHEAST
FLOW LOCALLY...AS SEEN IN THE LAST FEW ECMWF RUNS. WOULDNT RULE OUT
A FEW SPRINKLES OVER OUR SOUTHWEST AT TIMES THIS WEEKEND BUT
CONFIDENCE IS MUCH TOO LOW TO INCLUDE IN THE FORECAST. BAROCLINIC
ZONE WILL EVENTUALLY WORK ITS WAY EAST AS PACIFIC JET FORCES
DOWNSTREAM RIDGE TO SHIFT EASTWARD EARLY NEXT WEEK. LARGE
DISAGREEMENT IN LATEST MODELS ON HOW AND WHEN THIS WILL HAPPEN
THOUGH. WILL KEEP WITH PREVIOUS ECWMF PREFERENCE FOR NOW AND HOLD
OFF ON POPS UNTIL MIDWEEK. AFTER ANOTHER COOL DAY ON
SATURDAY...EXPECT A SLOW MODERATING TREND THROUGH EARLY NEXT WEEK AS
RIDGE AXIS PASSES OVERHEAD. TEMPS SHOULD RETURN TO AT OR ABOVE
NORMAL BY TUESDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM EDT THU MAY 23 2013

LAKE ENHANCED PORTION OF CDFNT APPEARS TO HAVE STALLED NEAR
SBN EARLY THIS MORNING RESULTING IN OCNL IFR CONDITIONS VARYING TO
VFR THERE. FRONT WILL RESUME S-SE MOVEMENT ACROSS NRN INDIANA TODAY
AS UPR LEVEL TROF MOVES THROUGH. THUS EXPECT TEMPO IFR WILL
TRANSITION TO PREDOMINANT IFR AT SBN AND MVFR AT FWA BY LATE
MORNING. MVFR CONDITIONS EXPECTED ACROSS THE AREA THIS
AFTN... TRANSITIONING TO VFR AND SKC THIS EVE. -SHRA WITH
CONSIDERABLE COVERAGE CONTG UPSTREAM ATTM SO ADJUSTED TEMPO -SHRA
TO ABOUT A 6HR PERIOD OF PREDOMINANT -SHRA TODAY IN LATEST TAFS.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT FROM 10 AM CDT THIS MORNING THROUGH
     FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT FROM 11 AM EDT THIS MORNING THROUGH
     FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
     FOR LMZ043-046.

&&

$$

SYNOPSIS...CEO/KG
SHORT TERM...JT
LONG TERM...AGD
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

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

000
FXUS63 KIWX 230809
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
409 AM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 407 AM EDT WED MAY 22 2013

A COLD FRONT EXTENDING ACROSS SOUTHERN MICHIGAN AND NORTHERN
ILLINOIS THIS MORNING... WILL MOVE SOUTH TO THE OHIO RIVER VALLEY THIS
EVENING. SHOWERS ARE LIKELY AS THE FRONTAL ZONE MOVES THROUGH THE
AREA. HIGH PRESSURE WILL MOVE SOUTH FROM CENTRAL CANADA INTO THE
GREAT LAKES AND OHIO VALLEY BEHIND THE FRONT TONIGHT... CAUSING
SKIES TO CLEAR AND UNSEASONABLY COOL TEMPERATURES TO OVERSPREAD
THE REGION.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 407 AM EDT THU MAY 23 2013

CUT-OFF UPR LEVEL LOW OVER THE MID MS VALLEY CONTS PROCESS OF
BEING ABSORBED BY TROF DIGGING S-SE ACROSS THE GRTLKS. SFC CDFNT
ASSOCIATED WITH THIS UPR TROF EXTENDED FROM SRN LAKE HURON TO JUST
SOUTH OF LAKE MICHIGAN AND THEN WNW ACROSS NRN IL. AREAS OF FOG
OCRG NEAR FRONT OVER SRN LAKE MICHIGAN AND EXTENDING SLIGHTLY
INLAND. FLOW LIGHT ENOUGH TO KEEP THIS FROM SPREADING VERY FAR
INLAND AND AS WINDS PICK UP...BOUNDARY LAYER MIXING SHOULD ALLOW
VSBYS TO IMPROVE NEAR THE LAKE EARLY THIS MORNING. A FAIRLY
WIDESPREAD AREA OF SHOWERS BEHIND THE FRONT ACROSS NRN IL... WI...
AND NW MI. FORCING RESPONSIBLE FOR THESE SHOWERS MAY WEAKEN SOME
TODAY AS UPR LOW CONTS TO SHEAR OUT... BUT EXPECT DIGGING UPR TROF
AND LIFT ALONG FRONTAL ZONE WILL BE SUFFICIENT TO MAINTAIN POST
FRONTAL SHOWERS MOVG SEWD ACROSS OUR AREA DURING THE DAY. SOME
SHOWERS MAY LINGER OVER SERN PORTION OF THE AREA EARLY THIS EVE
BUT SHOULD BE FOLLOWED BY CLEARING OVERNIGHT AS STRONG
SUBSIDENCE/DRYING OVERSPREADS THE CWA.

RATHER TIGHT PRESSURE GRADIENT BEHIND THE FRONT SHOULD RESULT IN
GUSTS UP TO 30MPH BEHIND THE FRONT TODAY... A LITTLE STRONGER IN
VCNTY OF LAKE MICHIGAN WHERE THERMAL GRADIENT ENHANCED. CONTG WITH
GALE WARNING FOR NSH ZONES AND SINCE BEACH SEASON HAS BEGUN...
ISSUED A BEACH HAZARD STATEMENT FOR THE SURF ZONE.

WITH STRONG CDFNT MOVG ACROSS THE AREA TODAY THERE WILL BE A TIGHT
TEMP GRADIENT WITH HIGHS EXPECTED TO RANGE FROM THE L50S NW TO THE
U60S SE. STRONG CAA TODAY/TONIGHT COMBINED WITH CLEARING SKIES
TONIGHT SHOULD ALLOW TEMPS TO FALL INTO THE U30S NORTH AND L40S
SOUTH. WITH SFC HIGH REMAINING TO THE WEST OF OUR AREA OVERNIGHT...
NORTHERLY GRADIENT EXPECTED TO BE STRONG ENOUGH TO MAINTAIN SOME
LIGHT WIND THROUGHOUT THE NIGHT WHICH SHOULD PREVENT A MORE SGFNT
TEMP DROP AND FROST FROM FORMING.

&&

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 407 AM EDT THU MAY 23 2013

REMARKABLY PLACID CONDITIONS TO BEGIN THIS LONG TERM PERIOD AS
BLOCKY HIGH AMPLITUDE WAVE TRAIN SLOWLY PROPAGATES
EASTWARD...LEAVING THE SOUTHERN GREAT LAKES ON SUBSIDENT SIDE OF
IMPRESSIVE MID/UPPER LEVEL RIDGE. 1030MB SURFACE ANTICYCLONE WILL BE
FIRMLY IN PLACE BY FRIDAY...LEADING TO A PLEASANT...ALBEIT SOMEWHAT
COOL...DAY. WILL BE INTERESTING TO SEE HOW WARM WE ACTUALLY GET WITH
THE STRONG LATE MAY SUN ANGLE ACTING ON CHILLY CP AIRMASS. THERMAL
TROUGH WILL BE PUSHING EASTWARD DURING THE DAY AND 850MB TEMPS LOOK
TO RECOVER TO AROUND 5C BY THE AFTERNOON. THIS WOULD USUALLY SUPPORT
HIGHS ONLY IN THE LOW 60S BUT FULL SUN SHOULD ALLOW FOR A GOOD
SUPERADIABATIC RESPONSE AT THE SURFACE...PUSHING HIGHS A FEW DEGREES
WARMER. WENT WITH GENERALLY MID 60S...SAVE FOR THE LAKESHORE AREAS
WHERE LIGHT NORTHERLY WINDS WILL ALLOW FOR DECENT MARINE INFLUENCE.
GOOD RADIATIONAL COOLING EXPECTED FRIDAY NIGHT. SURFACE HIGH WILL BE
DIRECTLY OVERHEAD WITH CALM WINDS AND FULL BOUNDARY LAYER
DECOUPLING. COULD BE SOME INCREASING CIRRUS TOWARD DAYBREAK BUT THE
EFFECT SHOULD BE MINIMAL AND EXPECT LOWS AROUND 40F ONCE AGAIN.
FROST IS NOT LIKELY GIVEN MARGINAL TEMPS AND VERY DRY AIRMASS.

FORECAST BECOMES A BIT MORE MUDDLED HEADING INTO THE HOLIDAY
WEEKEND. SEVERAL WEAK VORTICES ARE EXPECTED TO CASCADE DOWN THE
LONGWAVE RIDGE AND INCITE A DECENT WAA/FGEN RESPONSE TO OUR WEST.
QUESTION WILL BE WHETHER OR NOT THIS FORCING CAN CLIP OUR WESTERN
CWA. GIVEN THE STRENGTH OF CONFLUENCE ALOFT AND PERSISTENCE OF
GENERAL AVA IN SLOWLY PROGRESSING LARGE SCALE PATTERN...EXPECT
PRECIP WILL REMAIN CLOSELY TIED TO LOW LEVEL THETA-E GRADIENT DRAPED
OVER THE MIDWEST. PREPONDERANCE OF DRY AIR AND EFFECT OF COLD LAKES
THIS TIME OF YEAR SHOULD MAINTAIN HIGH PRESSURE AND DRY NORTHEAST
FLOW LOCALLY...AS SEEN IN THE LAST FEW ECMWF RUNS. WOULDNT RULE OUT
A FEW SPRINKLES OVER OUR SOUTHWEST AT TIMES THIS WEEKEND BUT
CONFIDENCE IS MUCH TOO LOW TO INCLUDE IN THE FORECAST. BAROCLINIC
ZONE WILL EVENTUALLY WORK ITS WAY EAST AS PACIFIC JET FORCES
DOWNSTREAM RIDGE TO SHIFT EASTWARD EARLY NEXT WEEK. LARGE
DISAGREEMENT IN LATEST MODELS ON HOW AND WHEN THIS WILL HAPPEN
THOUGH. WILL KEEP WITH PREVIOUS ECWMF PREFERENCE FOR NOW AND HOLD
OFF ON POPS UNTIL MIDWEEK. AFTER ANOTHER COOL DAY ON
SATURDAY...EXPECT A SLOW MODERATING TREND THROUGH EARLY NEXT WEEK AS
RIDGE AXIS PASSES OVERHEAD. TEMPS SHOULD RETURN TO AT OR ABOVE
NORMAL BY TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU MAY 23 2013

CDFNT ACCOMPANIED BY IFR CONDITIONS DROPPING S-SE ACROSS
WI-MI EARLY THIS MORNING. EXPECT FLYING CONDITIONS TO DETERIORATE
RATHER QUICKLY BEFORE DAWN AT SBN AS LAKE MICHIGAN MARINE LAYER
PUSHES INLAND. CONDITIONS THERE SHOULD IMPROVE TO MVFR THIS AFTN AND
VFR AGAIN BY THIS EVE. SLOWER DOWNWARD TREND FCST AT FWA WITH VFR
CONDITIONS LOWERING TO MVFR THIS MORNING AND PERSISTING THROUGH THE
AFTN BEFORE IMPROVING TO VFR THIS EVE. POST FRONTAL -SHRA UPSTREAM
OVER MI-WI ALSO EXPECTED TO SPREAD ACROSS NRN INDIANA TODAY.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT FROM 10 AM CDT THIS MORNING THROUGH
     FRIDAY EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT FROM 11 AM EDT THIS MORNING THROUGH
     FRIDAY EVENING FOR MIZ077.

OH...NONE.
LM...GALE WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
     FOR LMZ043-046.

&&

$$

SYNOPSIS...CEO/KG
SHORT TERM...JT
LONG TERM...AGD
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 230534
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
134 AM EDT THU MAY 23 2013

.SYNOPSIS...
ISSUED AT 508 PM EDT WED MAY 22 2013

A LOW PRESSURE SYSTEM CURRENTLY MAKING ITS WAY THROUGH THE REGION
WILL MOVE OFF INTO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT...WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

UPPER LOW CURRENTLY OVER S MN/N IA WILL CONTINUE TO
DROP SE INTO UPPER GREAT LAKES WITH ASSOCIATED SURFACE LOW OVER N IL
MOVING EAST ACROSS LWR MI THIS AFTERNOON INTO SOUTHERN ONTARIO BY
THURS MORNING. FIRST OF TWO COLD FRONTS IS CURRENTLY PROGRESSING
EASTWARD TOWARD NW IN THIS AFTERNOON. SHOWERS AND ISOLATED
THUNDERSTORMS HAVE FIRED AHEAD OF FRONT IN AREAS OF PARTIAL CLEARING
AS UPPER LVL VORT MAX ROTATES AROUND BASE OF TROF. ALTHO LL SHEAR
AND PWAT VALUES ARE DECENT...MEAGER DESTABILIZATION HAS OCCURRED
WITH WEAK MID LVL LAPSE RATES AND IS PREVENTING OVERALL
ORGANIZATION TO CONVECTION. LATEST HIRES MODELS HAVE CAPTURED
THIS FAIRLY WELL. THIS SHOULD LIMIT SEVERE POTENTIAL THIS
AFTERNOON INTO EVENING ACROSS MOST OF THE AREA WITH BEST FORCING
AND POTENTIAL TO THE FAR EAST OF CWA ACROSS EASTERN OH/WESTERN PA.
CANNOT RULE OUT A STRAY STRONG TO SEVERE STORM WITH GUSTY WINDS
BUT SUSPECT THIS IS LOW PROBABILITY. SCT SHOWERS WILL CONTINUE
OVERNIGHT TONIGHT INTO THURS BEFORE TAPERING OFF FROM WEST TO EAST
BY THURS EVENING AS SECONDARY COLD FRONT MOVES THRU. HAVE ONLY
MADE MINOR CHANGES TO POPS/WX GRIDS LATE TONIGHT INTO THURS.
GRADIENT IN TEMPS TONIGHT WITH LOWS AROUND 50 NEAR LK MI AND NEAR
60 IN THE SE. HIGHS WILL BE AROUND 10 TO 15 DEG COOLER ON THURS AS
COOLER AIR MOVES IN FROM THE NW BEHIND 2ND COLD FRONT.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

HIGH LATITUDE BLOCKING EXPECTED FRIDAY INTO THE HOLIDAY WEEKEND WITH
UPPER TROUGHS SETTING UP ALONG THE COASTS WITH AN OMEGA-LIKE UPPER
RIDGE ACROSS CENTRAL NORTH AMERICA. THIS WILL PLACE THE IWX CWA IN
COOL NORTHWEST FLOW ALOFT WITHIN DOWNSTREAM PORTION OF LARGE CENTRAL
CONUS UPPER RIDGE. DRY/BENIGN WX IS ANTICIPATED FRIDAY THROUGH
SUNDAY WITH SFC HIGH ANCHORED OVER THE GREAT LAKES AND ACTIVE LOW
LEVEL BAROCLINIC ZONE DISPLACED WELL WEST-SOUTHWEST OF THE LOCAL
AREA.

UPPER RIDGE WILL SHIFT EAST OVER THE AREA NEXT WEEK IN RESPONSE TO A
STRONG EAST PACIFIC JET CORE FORECAST TO INFILTRATE THE WESTERN US.
THIS WILL SUPPORT A SUBSTANTIAL MODERATING TREND MONDAY THROUGH
WEDNESDAY. MODELS TRY TO MIX THE INCREASINGLY DIFFUSE FRONTAL
BOUNDARY NORTH THROUGH THE AREA SOMETIME AROUND TUESDAY OR
WEDNESDAY...WITH THE GFS QUICKER/MORE PROGRESSIVE THAN THE PREFERRED
ECMWF SOLUTION. AS A RESULT CONTINUED TO HOLD WITH PREVIOUS DRY FCST
MONDAY AND TUESDAY AND ADDED LOW CHC POPS FOR SHOWERS/STORMS ON
WEDNESDAY. ONLY MADE MINOR TWEAKS TO TEMPS THROUGH THE PERIOD AS
FAVOR WARMER MOS HIGHS OVER THE 12Z MODEL CONSENSUS INITIATION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU MAY 23 2013

CDFNT ACCOMPANIED BY IFR CONDITIONS DROPPING S-SE ACROSS WI-MI
EARLY THIS MORNING. EXPECT FLYING CONDITIONS TO DETERIORATE
RATHER QUICKLY BEFORE DAWN AT SBN AS LAKE MICHIGAN MARINE LAYER
PUSHES INLAND. CONDITIONS THERE SHOULD IMPROVE TO MVFR THIS AFTN
AND VFR AGAIN BY THIS EVE. SLOWER DOWNWARD TREND FCST AT FWA WITH
VFR CONDITIONS LOWERING TO MVFR THIS MORNING AND PERSISTING
THROUGH THE AFTN BEFORE IMPROVING TO VFR THIS EVE. POST FRONTAL
-SHRA UPSTREAM OVER MI-WI ALSO EXPECTED TO SPREAD ACROSS NRN
INDIANA TODAY.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
     FOR LMZ043-046.

&&

$$

SYNOPSIS...CEO/KG
SHORT TERM...CEO
LONG TERM...STEINWEDEL
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 230057
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
857 PM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 508 PM EDT WED MAY 22 2013

A LOW PRESSURE SYSTEM CURRENTLY MAKING ITS WAY THROUGH THE REGION
WILL MOVE OFF INTO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT...WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

UPPER LOW CURRENTLY OVER S MN/N IA WILL CONTINUE TO
DROP SE INTO UPPER GREAT LAKES WITH ASSOCIATED SURFACE LOW OVER N IL
MOVING EAST ACROSS LWR MI THIS AFTERNOON INTO SOUTHERN ONTARIO BY
THURS MORNING. FIRST OF TWO COLD FRONTS IS CURRENTLY PROGRESSING
EASTWARD TOWARD NW IN THIS AFTERNOON. SHOWERS AND ISOLATED
THUNDERSTORMS HAVE FIRED AHEAD OF FRONT IN AREAS OF PARTIAL CLEARING
AS UPPER LVL VORT MAX ROTATES AROUND BASE OF TROF. ALTHO LL SHEAR
AND PWAT VALUES ARE DECENT...MEAGER DESTABILIZATION HAS OCCURRED
WITH WEAK MID LVL LAPSE RATES AND IS PREVENTING OVERALL
ORGANIZATION TO CONVECTION. LATEST HIRES MODELS HAVE CAPTURED
THIS FAIRLY WELL. THIS SHOULD LIMIT SEVERE POTENTIAL THIS
AFTERNOON INTO EVENING ACROSS MOST OF THE AREA WITH BEST FORCING
AND POTENTIAL TO THE FAR EAST OF CWA ACROSS EASTERN OH/WESTERN PA.
CANNOT RULE OUT A STRAY STRONG TO SEVERE STORM WITH GUSTY WINDS
BUT SUSPECT THIS IS LOW PROBABILITY. SCT SHOWERS WILL CONTINUE
OVERNIGHT TONIGHT INTO THURS BEFORE TAPERING OFF FROM WEST TO EAST
BY THURS EVENING AS SECONDARY COLD FRONT MOVES THRU. HAVE ONLY
MADE MINOR CHANGES TO POPS/WX GRIDS LATE TONIGHT INTO THURS.
GRADIENT IN TEMPS TONIGHT WITH LOWS AROUND 50 NEAR LK MI AND NEAR
60 IN THE SE. HIGHS WILL BE AROUND 10 TO 15 DEG COOLER ON THURS AS
COOLER AIR MOVES IN FROM THE NW BEHIND 2ND COLD FRONT.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

HIGH LATITUDE BLOCKING EXPECTED FRIDAY INTO THE HOLIDAY WEEKEND WITH
UPPER TROUGHS SETTING UP ALONG THE COASTS WITH AN OMEGA-LIKE UPPER
RIDGE ACROSS CENTRAL NORTH AMERICA. THIS WILL PLACE THE IWX CWA IN
COOL NORTHWEST FLOW ALOFT WITHIN DOWNSTREAM PORTION OF LARGE CENTRAL
CONUS UPPER RIDGE. DRY/BENIGN WX IS ANTICIPATED FRIDAY THROUGH
SUNDAY WITH SFC HIGH ANCHORED OVER THE GREAT LAKES AND ACTIVE LOW
LEVEL BAROCLINIC ZONE DISPLACED WELL WEST-SOUTHWEST OF THE LOCAL
AREA.

UPPER RIDGE WILL SHIFT EAST OVER THE AREA NEXT WEEK IN RESPONSE TO A
STRONG EAST PACIFIC JET CORE FORECAST TO INFILTRATE THE WESTERN US.
THIS WILL SUPPORT A SUBSTANTIAL MODERATING TREND MONDAY THROUGH
WEDNESDAY. MODELS TRY TO MIX THE INCREASINGLY DIFFUSE FRONTAL
BOUNDARY NORTH THROUGH THE AREA SOMETIME AROUND TUESDAY OR
WEDNESDAY...WITH THE GFS QUICKER/MORE PROGRESSIVE THAN THE PREFERRED
ECMWF SOLUTION. AS A RESULT CONTINUED TO HOLD WITH PREVIOUS DRY FCST
MONDAY AND TUESDAY AND ADDED LOW CHC POPS FOR SHOWERS/STORMS ON
WEDNESDAY. ONLY MADE MINOR TWEAKS TO TEMPS THROUGH THE PERIOD AS
FAVOR WARMER MOS HIGHS OVER THE 12Z MODEL CONSENSUS INITIATION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 855 PM EDT WED MAY 22 2013

WELL STABILIZED ATMOS IN WAKE OF SURFACE FRONTAL PASSAGE WITH LITTLE
MORE THAN WEAK SHRA REMAINDER OF NIGHT. CONCERN WITH STRATUS
FORMATION TOWARD DAYBREAK AS COOLING BOUNDARY LAYER CONTINUES TO
DEEPEN. STRONG PERTURBATION WITHIN SATURATED LAYER AS UPSTREAM MID
TROPOSPHERIC OCCLUDED LOW ACROSS EASTERN IOWA LIFTS OUT ACROSS
SOUTHERN GREAT LAKES. DETERIORATING CONDITIONS MOST LIKELY INTO FUEL
ALTERNATE BY 10 UTC ACROSS NORTHERN INDIANA WITH IFR MET CONDITIONS
EVEN PROBABLE AT KSBN WITH GREATER MAGNITUDE COOLING BELOW CROSSOVER
TEMPERATURE AND POTENTIAL MARINE LAYER INFLUENCE GIVEN STRONG
ONSHORE COMPONENT WITHIN LOWEST 100 MB IN 10-14 UTC TIMEFRAME.
CONTINUED 925MB COLD AIR ADVECTION WITH STRONG ISOTHERMAL GRADIENT
ALIGNED WITH SURFACE TROF AXIS THROUGH SOUTHERN ONTARIO TO
CHICAGOLAND AT 12 UTC THAT WILL SHUNT SEWD AMID 1030 MB SURFACE HIGH
ACROSS SOUTHERN CANADA INTRUDES INTO NW GREAT LAKES BY END OF
FORECAST PERIOD. INCREASINGLY SUBSIDENT AIRMASS WITH DRY AIR
ENTRAINMENT TO HELP BREAK/LIFT INTO BKN HIGH END MVFR CU DECK BY MID
AFTERNOON.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING FROM 10 AM TO 8 PM EDT THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...CEO/KG
SHORT TERM...CEO
LONG TERM...STEINWEDEL
AVIATION...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 222111
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
511 PM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 508 PM EDT WED MAY 22 2013

A LOW PRESSURE SYSTEM CURRENTLY MAKING ITS WAY THROUGH THE REGION
WILL MOVE OFF INTO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

UPPER LOW CURRENTLY OVER S MN/N IA WILL CONTINUE TO
DROP SE INTO UPPER GREAT LAKES WITH ASSOCIATED SURFACE LOW OVER N IL
MOVING EAST ACROSS LWR MI THIS AFTERNOON INTO SOUTHERN ONTARIO BY
THURS MORNING. FIRST OF TWO COLD FRONTS IS CURRENTLY PROGRESSING
EASTWARD TOWARD NW IN THIS AFTERNOON. SHOWERS AND ISOLATED
THUNDERSTORMS HAVE FIRED AHEAD OF FRONT IN AREAS OF PARTIAL CLEARING
AS UPPER LVL VORT MAX ROTATES AROUND BASE OF TROF. ALTHO LL SHEAR
AND PWAT VALUES ARE DECENT...MEAGER DESTABILIZATION HAS OCCURRED
WITH WEAK MID LVL LAPSE RATES AND IS PREVENTING OVERALL
ORGANIZATION TO CONVECTION. LATEST HIRES MODELS HAVE CAPTURED
THIS FAIRLY WELL. THIS SHOULD LIMIT SEVERE POTENTIAL THIS
AFTERNOON INTO EVENING ACROSS MOST OF THE AREA WITH BEST FORCING
AND POTENTIAL TO THE FAR EAST OF CWA ACROSS EASTERN OH/WESTERN PA.
CANNOT RULE OUT A STRAY STRONG TO SEVERE STORM WITH GUSTY WINDS
BUT SUSPECT THIS IS LOW PROBABILITY. SCT SHOWERS WILL CONTINUE
OVERNIGHT TONIGHT INTO THURS BEFORE TAPERING OFF FROM WEST TO EAST
BY THURS EVENING AS SECONDARY COLD FRONT MOVES THRU. HAVE ONLY
MADE MINOR CHANGES TO POPS/WX GRIDS LATE TONIGHT INTO THURS.
GRADIENT IN TEMPS TONIGHT WITH LOWS AROUND 50 NEAR LK MI AND NEAR
60 IN THE SE. HIGHS WILL BE AROUND 10 TO 15 DEG COOLER ON THURS AS
COOLER AIR MOVES IN FROM THE NW BEHIND 2ND COLD FRONT.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

HIGH LATITUDE BLOCKING EXPECTED FRIDAY INTO THE HOLIDAY WEEKEND WITH
UPPER TROUGHS SETTING UP ALONG THE COASTS WITH AN OMEGA-LIKE UPPER
RIDGE ACROSS CENTRAL NORTH AMERICA. THIS WILL PLACE THE IWX CWA IN
COOL NORTHWEST FLOW ALOFT WITHIN DOWNSTREAM PORTION OF LARGE CENTRAL
CONUS UPPER RIDGE. DRY/BENIGN WX IS ANTICIPATED FRIDAY THROUGH
SUNDAY WITH SFC HIGH ANCHORED OVER THE GREAT LAKES AND ACTIVE LOW
LEVEL BAROCLINIC ZONE DISPLACED WELL WEST-SOUTHWEST OF THE LOCAL
AREA.

UPPER RIDGE WILL SHIFT EAST OVER THE AREA NEXT WEEK IN RESPONSE TO A
STRONG EAST PACIFIC JET CORE FORECAST TO INFILTRATE THE WESTERN US.
THIS WILL SUPPORT A SUBSTANTIAL MODERATING TREND MONDAY THROUGH
WEDNESDAY. MODELS TRY TO MIX THE INCREASINGLY DIFFUSE FRONTAL
BOUNDARY NORTH THROUGH THE AREA SOMETIME AROUND TUESDAY OR
WEDNESDAY...WITH THE GFS QUICKER/MORE PROGRESSIVE THAN THE PREFERRED
ECMWF SOLUTION. AS A RESULT CONTINUED TO HOLD WITH PREVIOUS DRY FCST
MONDAY AND TUESDAY AND ADDED LOW CHC POPS FOR SHOWERS/STORMS ON
WEDNESDAY. ONLY MADE MINOR TWEAKS TO TEMPS THROUGH THE PERIOD AS
FAVOR WARMER MOS HIGHS OVER THE 12Z MODEL CONSENSUS INITIATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 117 PM EDT WED MAY 22 2013

SCATTERED SHOWERS BEGINNING TO FIRE ACROSS AREA AHEAD OF FIRST OF
TWO COLD FRONTS AS SUBTLE DESTABILIZATION IS OCCURRING IN AREAS OF
PARTIAL CLEARING. VFR CONDITIONS PRESENT AT TAF ISSUANCE BUT MVFR
CONDITIONS LIKELY FROM TIME TO TIME AT BOTH TERMINALS DURING
PERIODS OF HEAVIER SHOWERS AND ISOLATED TSRA THIS AFTERNOON INTO
EVENING. STILL UNCERTAIN ON TIMING AND COVERAGE SO HAVE COVERED
THIS WITH TEMPO GROUP THROUGH 21-22Z AT BOTH TERMINALS. SHOWERS
WILL LINGER OVERNIGHT INTO THE MORNING HOURS AS SECONDARY COLD
FRONT MOVES THRU AREA. MODELS HINTING AT PERIOD OF IFR OR EVEN
LIFR CONDITIONS AFTER 6Z WITH FROPA. HAVE TRENDED VISBY AND CIGS DOWN
A BIT BUT HESITANT TO DETERIORATE CONDITIONS THAT MUCH UNTIL
TRENDS CAN BE BETTER NAILED DOWN. WINDS WILL BE IN THE 8 TO 15 KT
RANGE FOR THE PERIOD AND WILL VEER FROM SW THIS AFTERNOON TO NW BY
LATE THURS MORNING.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WARNING FROM 10 AM TO 8 PM EDT THURSDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...CEO/KG
SHORT TERM...CEO
LONG TERM...STEINWEDEL
AVIATION...CEO


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 221925
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
325 PM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 1150 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHWEST ILLINOIS WILL MOVE EAST ACROSS SOUTHERN LOWER
MICHIGAN THIS AFTERNOON AND TO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

UPPER LOW CURRENTLY OVER S MN/N IA WILL CONTINUE TO
DROP SE INTO UPPER GREAT LAKES WITH ASSOCIATED SURFACE LOW OVER N IL
MOVING EAST ACROSS LWR MI THIS AFTERNOON INTO SOUTHERN ONTARIO BY
THURS MORNING. FIRST OF TWO COLD FRONTS IS CURRENTLY PROGRESSING
EASTWARD TOWARD NW IN THIS AFTERNOON. SHOWERS AND ISOLATED
THUNDERSTORMS HAVE FIRED AHEAD OF FRONT IN AREAS OF PARTIAL CLEARING
AS UPPER LVL VORT MAX ROTATES AROUND BASE OF TROF. ALTHO LL SHEAR
AND PWAT VALUES ARE DECENT...MEAGER DESTABILIZATION HAS OCCURRED
WITH WEAK MID LVL LAPSE RATES AND IS PREVENTING OVERALL
ORGANIZATION TO CONVECTION. LATEST HIRES MODELS HAVE CAPTURED
THIS FAIRLY WELL. THIS SHOULD LIMIT SEVERE POTENTIAL THIS
AFTERNOON INTO EVENING ACROSS MOST OF THE AREA WITH BEST FORCING
AND POTENTIAL TO THE FAR EAST OF CWA ACROSS EASTERN OH/WESTERN PA.
CANNOT RULE OUT A STRAY STRONG TO SEVERE STORM WITH GUSTY WINDS
BUT SUSPECT THIS IS LOW PROBABILITY. SCT SHOWERS WILL CONTINUE
OVERNIGHT TONIGHT INTO THURS BEFORE TAPERING OFF FROM WEST TO EAST
BY THURS EVENING AS SECONDARY COLD FRONT MOVES THRU. HAVE ONLY
MADE MINOR CHANGES TO POPS/WX GRIDS LATE TONIGHT INTO THURS.
GRADIENT IN TEMPS TONIGHT WITH LOWS AROUND 50 NEAR LK MI AND NEAR
60 IN THE SE. HIGHS WILL BE AROUND 10 TO 15 DEG COOLER ON THURS AS
COOLER AIR MOVES IN FROM THE NW BEHIND 2ND COLD FRONT.


&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 321 PM EDT WED MAY 22 2013

HIGH LATITUDE BLOCKING EXPECTED FRIDAY INTO THE HOLIDAY WEEKEND WITH
UPPER TROUGHS SETTING UP ALONG THE COASTS WITH AN OMEGA-LIKE UPPER
RIDGE ACROSS CENTRAL NORTH AMERICA. THIS WILL PLACE THE IWX CWA IN
COOL NORTHWEST FLOW ALOFT WITHIN DOWNSTREAM PORTION OF LARGE CENTRAL
CONUS UPPER RIDGE. DRY/BENIGN WX IS ANTICIPATED FRIDAY THROUGH
SUNDAY WITH SFC HIGH ANCHORED OVER THE GREAT LAKES AND ACTIVE LOW
LEVEL BAROCLINIC ZONE DISPLACED WELL WEST-SOUTHWEST OF THE LOCAL
AREA.

UPPER RIDGE WILL SHIFT EAST OVER THE AREA NEXT WEEK IN RESPONSE TO A
STRONG EAST PACIFIC JET CORE FORECAST TO INFILTRATE THE WESTERN US.
THIS WILL SUPPORT A SUBSTANTIAL MODERATING TREND MONDAY THROUGH
WEDNESDAY. MODELS TRY TO MIX THE INCREASINGLY DIFFUSE FRONTAL
BOUNDARY NORTH THROUGH THE AREA SOMETIME AROUND TUESDAY OR
WEDNESDAY...WITH THE GFS QUICKER/MORE PROGRESSIVE THAN THE PREFERRED
ECMWF SOLUTION. AS A RESULT CONTINUED TO HOLD WITH PREVIOUS DRY FCST
MONDAY AND TUESDAY AND ADDED LOW CHC POPS FOR SHOWERS/STORMS ON
WEDNESDAY. ONLY MADE MINOR TWEAKS TO TEMPS THROUGH THE PERIOD AS
FAVOR WARMER MOS HIGHS OVER THE 12Z MODEL CONSENSUS INITIATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 117 PM EDT WED MAY 22 2013

SCATTERED SHOWERS BEGINNING TO FIRE ACROSS AREA AHEAD OF FIRST OF
TWO COLD FRONTS AS SUBTLE DESTABILIZATION IS OCCURRING IN AREAS OF
PARTIAL CLEARING. VFR CONDITIONS PRESENT AT TAF ISSUANCE BUT MVFR
CONDITIONS LIKELY FROM TIME TO TIME AT BOTH TERMINALS DURING
PERIODS OF HEAVIER SHOWERS AND ISOLATED TSRA THIS AFTERNOON INTO
EVENING. STILL UNCERTAIN ON TIMING AND COVERAGE SO HAVE COVERED
THIS WITH TEMPO GROUP THROUGH 21-22Z AT BOTH TERMINALS. SHOWERS
WILL LINGER OVERNIGHT INTO THE MORNING HOURS AS SECONDARY COLD
FRONT MOVES THRU AREA. MODELS HINTING AT PERIOD OF IFR OR EVEN
LIFR CONDITIONS AFTER 6Z WITH FROPA. HAVE TRENDED VISBY AND CIGS DOWN
A BIT BUT HESITANT TO DETERIORATE CONDITIONS THAT MUCH UNTIL
TRENDS CAN BE BETTER NAILED DOWN. WINDS WILL BE IN THE 8 TO 15 KT
RANGE FOR THE PERIOD AND WILL VEER FROM SW THIS AFTERNOON TO NW BY
LATE THURS MORNING.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR
     LMZ043-046.

&&

$$

SYNOPSIS...CEO
SHORT TERM...CEO
LONG TERM...STEINWEDEL
AVIATION...CEO


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 221729
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
129 PM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 1150 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHWEST ILLINOIS WILL MOVE EAST ACROSS SOUTHERN LOWER
MICHIGAN THIS AFTERNOON AND TO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.UPDATE...
ISSUED AT 1150 AM EDT WED MAY 22 2013

MINOR UPDATE TO GRIDS MAINLY TO ACCOUNT FOR SLOWER RISE IN TEMPS
THIS MORNING DUE TO EXTENSIVE CLOUD COVER AND SCATTERED SHOWERS
ACROSS AREA. HIGHS MAY STRUGGLE TO MAKE IT OUT OF THE MID 70S AND
HAVE LOWERED HIGHS A DEGREE OR TWO...ESP ACROSS NW OHIO ZONES.
AFTERNOON FORECAST STILL A BIT UNCERTAIN IN TERMS OF CONVECTIVE
DEVELOPMENT AND SEVERE POTENTIAL. CONVECTION ATTEMPTING TO FIRE
ALONG COLD FRONT BACK IN CENTRAL ILLINOIS WITH ANOTHER AREA JUST TO
THE NORTH THAT DEVELOPED IN AREA OF PARTIAL CLEARING. LATEST HIRES
MODELS SHOW STORMS MOVING INTO AREA AFTER 18Z AND MOVING EAST INTO
NW OHIO BY EARLY EVENING. SLIGHT RISK OF SEVERE REMAINS MAINLY
EAST OF I69 WITH BEST CHANCES TO EAST OF CWA. EVEN THOUGH LL SHEAR IS
DECENT WITH FORCING FROM UPPER LEVEL WAVE ROTATING AROUND BASE OF
TROUGH...INSTABILITY WILL BE MARGINAL AND WILL DEPEND ON HOW MUCH
CLEARING TAKES PLACE OVER NEXT SEVERAL HOURS. WILL RIDE WITH GOING
POPS/WX GRIDS UNTIL FORECAST SPECIFICS AND TIMING CAN BE BETTER
NAILED DOWN.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT WED MAY 22 2013

UPR LOW OVER SRN MN EXPECTED TO MOVE ESE TODAY/TNGT AND GRDLY
SHEAR OUT/MERGE WITH NRN STREAM TROF DROPPING SOUTH FROM HUDSON
BAY TO THE UPR GRTLKS. ASSOCIATED BROAD SFC LOW SHOULD MOVE EAST
FROM IA ACROSS SRN LWR MI TODAY AND INTO SRN ONTARIO TONIGHT WITH
AN ACCOMPANYING WK COOL FRONT MOVG EAST ACROSS OUR CWA.
COMBINATION OF WK UVM ASSOCIATED WITH THESE FEATURES AND SOME
DIURNAL DESTABILIZATION EXPECTED TO RESULT IN SHOWERS/TSTMS IN THE
AREA... MAINLY THIS AFTN. AFTN CAPE EXPECTED TO BE 1000-1500J/KG
WITH 30-35KT 0-6KM SHEAR AND STEEP LOW LEVEL LAPSE RATES. THIS MAY
ALLOW SOME OF THE STORMS TO BECOME SEVERE WITH DAMAGING WINDS AND
LARGE HAIL PSBL THIS AFTN... PARTICULARLY OVER NW OH WHERE FROPA
WILL BE LATER ALLOWING FOR BETTER OPPORTUNITY TO DESTABILIZE.

A STRONGER CDFNT ASSOCIATED WITH THE APCHG NRN STREAM TROF SHOULD
DROP INTO SRN LM BY DAWN THU. FORCING TONIGHT HWVR SHOULD BE
WEAKER AS MID/UPR LEVEL WIND FIELD OVER THE AREA GRDLY WEAKENS AS
UPR LOW SHEARS OUT. GIVEN THIS SCENARIO... STAYED CLOSE TO
INHERITED CHC POP GRIDS FOR TONIGHT.

HIGHS TODAY GENERALLY FCST A FEW DEGREES ABOVE MOS BASED ON
RECENT COOL BIAS AND MILD START TO THE DAY. COOL FRONT SHOULD
RESULT IN A LITTLE LOWER MINS TONIGHT... RANGING FROM AROUND 50
NEAR LAKE MICHIGAN TO AROUND 60 FAR SE.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 440 AM EDT WED MAY 22 2013

A SECONDARY UPPER LEVEL TROF WILL MOVE SOUTHEAST ACROSS THE WESTERN
GREAT LAKES REGION THURSDAY AS COOLER AIR SPREADS SOUTHEAST. THE
UPPER LEVEL SUPPORT SHOULD BE SUFFICIENT TO PRODUCE SHOWERS...
ALTHOUGH THERE SHOULD BE A WELL DEFINED NW EDGE/ENDING OF THE
PRECIPITATION GIVEN THE SUBSIDENCE BEHIND THE TROF. PUT SOME DETAIL
IN THE GRIDS IN THIS REGARD THURSDAY WITH THE BEST CHANCE FOR RAIN
EARLY IN THE DAY. ADDED PATCHY FROST NORTHERN AREAS THURSDAY NIGHT.
SKIES SHOULD CLEAR WITH WINDS BECOMING LIGHT MOST AREAS. OTHERWISE...
KEPT THE REST OF THE FORECAST DRY. SPECTRAL MODELS PROVIDING A RANGE
OF HANDLING THE SHORT WAVE ENERGY MOVING EAST AS THE UPPER LEVEL
RIDGE AMPLIFIES OVER THE EASTERN HALF OF THE CONUS. THE ECMWF KEEP
THE ENTIRE PERIOD DRY AND APPEARS REASONABLE WITH THIS SOLUTION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 117 PM EDT WED MAY 22 2013

SCATTERED SHOWERS BEGINNING TO FIRE ACROSS AREA AHEAD OF FIRST OF
TWO COLD FRONTS AS SUBTLE DESTABILIZATION IS OCCURRING IN AREAS OF
PARTIAL CLEARING. VFR CONDITIONS PRESENT AT TAF ISSUANCE BUT MVFR
CONDITIONS LIKELY FROM TIME TO TIME AT BOTH TERMINALS DURING
PERIODS OF HEAVIER SHOWERS AND ISOLATED TSRA THIS AFTERNOON INTO
EVENING. STILL UNCERTAIN ON TIMING AND COVERAGE SO HAVE COVERED
THIS WITH TEMPO GROUP THROUGH 21-22Z AT BOTH TERMINALS. SHOWERS
WILL LINGER OVERNIGHT INTO THE MORNING HOURS AS SECONDARY COLD
FRONT MOVES THRU AREA. MODELS HINTING AT PERIOD OF IFR OR EVEN
LIFR CONDITIONS AFTER 6Z WITH FROPA. HAVE TRENDED VISBY AND CIGS DOWN
A BIT BUT HESITANT TO DETERIORATE CONDITIONS THAT MUCH UNTIL
TRENDS CAN BE BETTER NAILED DOWN. WINDS WILL BE IN THE 8 TO 15 KT
RANGE FOR THE PERIOD AND WILL VEER FROM SW THIS AFTERNOON TO NW BY
LATE THURS MORNING.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR
     LMZ043-046.

&&

$$

UPDATE...CEO
SYNOPSIS...CEO
SHORT TERM...JT
LONG TERM...SKIPPER
AVIATION...CEO


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 221603
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1203 PM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 1150 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHWEST ILLINOIS WILL MOVE EAST ACROSS SOUTHERN LOWER
MICHIGAN THIS AFTERNOON AND TO SOUTHERN ONTARIO TONIGHT. A WEAK COOL FRONT
WILL TRAIL TO THE SOUTH OF THE LOW AND MOVE EAST ACROSS SOUTHERN
MICHIGAN... INDIANA... AND MOST OF OHIO BY THURSDAY MORNING...
WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH ACROSS THE UPPER
GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED
ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE SCATTERED SHOWERS
MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.UPDATE...
ISSUED AT 1150 AM EDT WED MAY 22 2013

MINOR UPDATE TO GRIDS MAINLY TO ACCOUNT FOR SLOWER RISE IN TEMPS
THIS MORNING DUE TO EXTENSIVE CLOUD COVER AND SCATTERED SHOWERS
ACROSS AREA. HIGHS MAY STRUGGLE TO MAKE IT OUT OF THE MID 70S AND
HAVE LOWERED HIGHS A DEGREE OR TWO...ESP ACROSS NW OHIO ZONES.
AFTERNOON FORECAST STILL A BIT UNCERTAIN IN TERMS OF CONVECTIVE
DEVELOPMENT AND SEVERE POTENTIAL. CONVECTION ATTEMPTING TO FIRE
ALONG COLD FRONT BACK IN CENTRAL ILLINOIS WITH ANOTHER AREA JUST TO
THE NORTH THAT DEVELOPED IN AREA OF PARTIAL CLEARING. LATEST HIRES
MODELS SHOW STORMS MOVING INTO AREA AFTER 18Z AND MOVING EAST INTO
NW OHIO BY EARLY EVENING. SLIGHT RISK OF SEVERE REMAINS MAINLY
EAST OF I69 WITH BEST CHANCES TO EAST OF CWA. EVEN THOUGH LL SHEAR IS
DECENT WITH FORCING FROM UPPER LEVEL WAVE ROTATING AROUND BASE OF
TROUGH...INSTABILITY WILL BE MARGINAL AND WILL DEPEND ON HOW MUCH
CLEARING TAKES PLACE OVER NEXT SEVERAL HOURS. WILL RIDE WITH GOING
POPS/WX GRIDS UNTIL FORECAST SPECIFICS AND TIMING CAN BE BETTER
NAILED DOWN.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT WED MAY 22 2013

UPR LOW OVER SRN MN EXPECTED TO MOVE ESE TODAY/TNGT AND GRDLY
SHEAR OUT/MERGE WITH NRN STREAM TROF DROPPING SOUTH FROM HUDSON
BAY TO THE UPR GRTLKS. ASSOCIATED BROAD SFC LOW SHOULD MOVE EAST
FROM IA ACROSS SRN LWR MI TODAY AND INTO SRN ONTARIO TONIGHT WITH
AN ACCOMPANYING WK COOL FRONT MOVG EAST ACROSS OUR CWA.
COMBINATION OF WK UVM ASSOCIATED WITH THESE FEATURES AND SOME
DIURNAL DESTABILIZATION EXPECTED TO RESULT IN SHOWERS/TSTMS IN THE
AREA... MAINLY THIS AFTN. AFTN CAPE EXPECTED TO BE 1000-1500J/KG
WITH 30-35KT 0-6KM SHEAR AND STEEP LOW LEVEL LAPSE RATES. THIS MAY
ALLOW SOME OF THE STORMS TO BECOME SEVERE WITH DAMAGING WINDS AND
LARGE HAIL PSBL THIS AFTN... PARTICULARLY OVER NW OH WHERE FROPA
WILL BE LATER ALLOWING FOR BETTER OPPORTUNITY TO DESTABILIZE.

A STRONGER CDFNT ASSOCIATED WITH THE APCHG NRN STREAM TROF SHOULD
DROP INTO SRN LM BY DAWN THU. FORCING TONIGHT HWVR SHOULD BE
WEAKER AS MID/UPR LEVEL WIND FIELD OVER THE AREA GRDLY WEAKENS AS
UPR LOW SHEARS OUT. GIVEN THIS SCENARIO... STAYED CLOSE TO
INHERITED CHC POP GRIDS FOR TONIGHT.

HIGHS TODAY GENERALLY FCST A FEW DEGREES ABOVE MOS BASED ON
RECENT COOL BIAS AND MILD START TO THE DAY. COOL FRONT SHOULD
RESULT IN A LITTLE LOWER MINS TONIGHT... RANGING FROM AROUND 50
NEAR LAKE MICHIGAN TO AROUND 60 FAR SE.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 440 AM EDT WED MAY 22 2013

A SECONDARY UPPER LEVEL TROF WILL MOVE SOUTHEAST ACROSS THE WESTERN
GREAT LAKES REGION THURSDAY AS COOLER AIR SPREADS SOUTHEAST. THE
UPPER LEVEL SUPPORT SHOULD BE SUFFICIENT TO PRODUCE SHOWERS...
ALTHOUGH THERE SHOULD BE A WELL DEFINED NW EDGE/ENDING OF THE
PRECIPITATION GIVEN THE SUBSIDENCE BEHIND THE TROF. PUT SOME DETAIL
IN THE GRIDS IN THIS REGARD THURSDAY WITH THE BEST CHANCE FOR RAIN
EARLY IN THE DAY. ADDED PATCHY FROST NORTHERN AREAS THURSDAY NIGHT.
SKIES SHOULD CLEAR WITH WINDS BECOMING LIGHT MOST AREAS. OTHERWISE...
KEPT THE REST OF THE FORECAST DRY. SPECTRAL MODELS PROVIDING A RANGE
OF HANDLING THE SHORT WAVE ENERGY MOVING EAST AS THE UPPER LEVEL
RIDGE AMPLIFIES OVER THE EASTERN HALF OF THE CONUS. THE ECMWF KEEP
THE ENTIRE PERIOD DRY AND APPEARS REASONABLE WITH THIS SOLUTION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM EDT WED MAY 22 2013

AN AREA OF SHRA OVER INDIANA AHEAD OF SHRTWV LIFTING N-NE AROUND
UPR MIDWEST LOW IS EXPECTED TO IMPACT THE TERMINALS THIS MORNING
WITH MVFR CONDITIONS. PREDOMINANTLY VFR CONDITIONS EXPECTED THIS
AFTN BUT DIURNAL DESTABILIZATION AND APCHG COOL FRONT WILL LIKELY
RESULT IN SCT TS WITH LOCALLY LOWER FLYING CONDITIONS ACROSS NRN
INDIANA LATER TODAY. THERE IS HWVR STILL CONSIDERABLE UNCERTAINTY
ON TIMING AND EVEN OCCURRENCE OF DEEP CONVECTION OVER NRN INDIANA
THIS AFTN AS CLOUD COVER COULD DELAY OR PREVENT SGFNT
DESTABILIZATION. A SECOND CDFNT WILL APPROACH THE AREA FROM THE
NORTH LATE TONIGHT AND SHOULD RESULT IN LOWERING CIGS/VSBYS BY
DAWN THU.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR
     LMZ043-046.

&&

$$

UPDATE...CEO
SYNOPSIS...CEO
SHORT TERM...JT
LONG TERM...SKIPPER
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 221027
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
627 AM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 355 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHEAST IOWA THIS MORNING WILL MOVE EAST
ACROSS SOUTHERN LOWER MICHIGAN TODAY AND TO SOUTHERN ONTARIO
TONIGHT. A WEAK COOL FRONT WILL TRAIL TO THE SOUTH OF THE LOW AND
MOVE EAST ACROSS SOUTHERN MICHIGAN... INDIANA... AND MOST OF OHIO BY
THURSDAY MORNING... WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH
ACROSS THE UPPER GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE
SCATTERED SHOWERS MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT WED MAY 22 2013

UPR LOW OVER SRN MN EXPECTED TO MOVE ESE TODAY/TNGT AND GRDLY
SHEAR OUT/MERGE WITH NRN STREAM TROF DROPPING SOUTH FROM HUDSON
BAY TO THE UPR GRTLKS. ASSOCIATED BROAD SFC LOW SHOULD MOVE EAST
FROM IA ACROSS SRN LWR MI TODAY AND INTO SRN ONTARIO TONIGHT WITH
AN ACCOMPANYING WK COOL FRONT MOVG EAST ACROSS OUR CWA.
COMBINATION OF WK UVM ASSOCIATED WITH THESE FEATURES AND SOME
DIURNAL DESTABILIZATION EXPECTED TO RESULT IN SHOWERS/TSTMS IN THE
AREA... MAINLY THIS AFTN. AFTN CAPE EXPECTED TO BE 1000-1500J/KG
WITH 30-35KT 0-6KM SHEAR AND STEEP LOW LEVEL LAPSE RATES. THIS MAY
ALLOW SOME OF THE STORMS TO BECOME SEVERE WITH DAMAGING WINDS AND
LARGE HAIL PSBL THIS AFTN... PARTICULARLY OVER NW OH WHERE FROPA
WILL BE LATER ALLOWING FOR BETTER OPPORTUNITY TO DESTABILIZE.

A STRONGER CDFNT ASSOCIATED WITH THE APCHG NRN STREAM TROF SHOULD
DROP INTO SRN LM BY DAWN THU. FORCING TONIGHT HWVR SHOULD BE
WEAKER AS MID/UPR LEVEL WIND FIELD OVER THE AREA GRDLY WEAKENS AS
UPR LOW SHEARS OUT. GIVEN THIS SCENARIO... STAYED CLOSE TO
INHERITED CHC POP GRIDS FOR TONIGHT.

HIGHS TODAY GENERALLY FCST A FEW DEGREES ABOVE MOS BASED ON
RECENT COOL BIAS AND MILD START TO THE DAY. COOL FRONT SHOULD
RESULT IN A LITTLE LOWER MINS TONIGHT... RANGING FROM AROUND 50
NEAR LAKE MICHIGAN TO AROUND 60 FAR SE.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 440 AM EDT WED MAY 22 2013

A SECONDARY UPPER LEVEL TROF WILL MOVE SOUTHEAST ACROSS THE WESTERN
GREAT LAKES REGION THURSDAY AS COOLER AIR SPREADS SOUTHEAST. THE
UPPER LEVEL SUPPORT SHOULD BE SUFFICIENT TO PRODUCE SHOWERS...
ALTHOUGH THERE SHOULD BE A WELL DEFINED NW EDGE/ENDING OF THE
PRECIPITATION GIVEN THE SUBSIDENCE BEHIND THE TROF. PUT SOME DETAIL
IN THE GRIDS IN THIS REGARD THURSDAY WITH THE BEST CHANCE FOR RAIN
EARLY IN THE DAY. ADDED PATCHY FROST NORTHERN AREAS THURSDAY NIGHT.
SKIES SHOULD CLEAR WITH WINDS BECOMING LIGHT MOST AREAS. OTHERWISE...
KEPT THE REST OF THE FORECAST DRY. SPECTRAL MODELS PROVIDING A RANGE
OF HANDLING THE SHORT WAVE ENERGY MOVING EAST AS THE UPPER LEVEL
RIDGE AMPLIFIES OVER THE EASTERN HALF OF THE CONUS. THE ECMWF KEEP
THE ENTIRE PERIOD DRY AND APPEARS REASONABLE WITH THIS SOLUTION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 626 AM EDT WED MAY 22 2013

AN AREA OF SHRA OVER INDIANA AHEAD OF SHRTWV LIFTING N-NE AROUND
UPR MIDWEST LOW IS EXPECTED TO IMPACT THE TERMINALS THIS MORNING
WITH MVFR CONDITIONS. PREDOMINANTLY VFR CONDITIONS EXPECTED THIS
AFTN BUT DIURNAL DESTABILIZATION AND APCHG COOL FRONT WILL LIKELY
RESULT IN SCT TS WITH LOCALLY LOWER FLYING CONDITIONS ACROSS NRN
INDIANA LATER TODAY. THERE IS HWVR STILL CONSIDERABLE UNCERTAINTY
ON TIMING AND EVEN OCCURRENCE OF DEEP CONVECTION OVER NRN INDIANA
THIS AFTN AS CLOUD COVER COULD DELAY OR PREVENT SGFNT
DESTABILIZATION. A SECOND CDFNT WILL APPROACH THE AREA FROM THE
NORTH LATE TONIGHT AND SHOULD RESULT IN LOWERING CIGS/VSBYS BY
DAWN THU.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR
     LMZ043-046.

&&

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...SKIPPER
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 220851
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
451 AM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 355 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHEAST IOWA THIS MORNING WILL MOVE EAST
ACROSS SOUTHERN LOWER MICHIGAN TODAY AND TO SOUTHERN ONTARIO
TONIGHT. A WEAK COOL FRONT WILL TRAIL TO THE SOUTH OF THE LOW AND
MOVE EAST ACROSS SOUTHERN MICHIGAN... INDIANA... AND MOST OF OHIO BY
THURSDAY MORNING... WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH
ACROSS THE UPPER GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE
SCATTERED SHOWERS MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 440 AM EDT WED MAY 22 2013

UPR LOW OVER SRN MN EXPECTED TO MOVE ESE TODAY/TNGT AND GRDLY
SHEAR OUT/MERGE WITH NRN STREAM TROF DROPPING SOUTH FROM HUDSON
BAY TO THE UPR GRTLKS. ASSOCIATED BROAD SFC LOW SHOULD MOVE EAST
FROM IA ACROSS SRN LWR MI TODAY AND INTO SRN ONTARIO TONIGHT WITH
AN ACCOMPANYING WK COOL FRONT MOVG EAST ACROSS OUR CWA.
COMBINATION OF WK UVM ASSOCIATED WITH THESE FEATURES AND SOME
DIURNAL DESTABILIZATION EXPECTED TO RESULT IN SHOWERS/TSTMS IN THE
AREA... MAINLY THIS AFTN. AFTN CAPE EXPECTED TO BE 1000-1500J/KG
WITH 30-35KT 0-6KM SHEAR AND STEEP LOW LEVEL LAPSE RATES. THIS MAY
ALLOW SOME OF THE STORMS TO BECOME SEVERE WITH DAMAGING WINDS AND
LARGE HAIL PSBL THIS AFTN... PARTICULARLY OVER NW OH WHERE FROPA
WILL BE LATER ALLOWING FOR BETTER OPPORTUNITY TO DESTABILIZE.

A STRONGER CDFNT ASSOCIATED WITH THE APCHG NRN STREAM TROF SHOULD
DROP INTO SRN LM BY DAWN THU. FORCING TONIGHT HWVR SHOULD BE
WEAKER AS MID/UPR LEVEL WIND FIELD OVER THE AREA GRDLY WEAKENS AS
UPR LOW SHEARS OUT. GIVEN THIS SCENARIO... STAYED CLOSE TO
INHERITED CHC POP GRIDS FOR TONIGHT.

HIGHS TODAY GENERALLY FCST A FEW DEGREES ABOVE MOS BASED ON
RECENT COOL BIAS AND MILD START TO THE DAY. COOL FRONT SHOULD
RESULT IN A LITTLE LOWER MINS TONIGHT... RANGING FROM AROUND 50
NEAR LAKE MICHIGAN TO AROUND 60 FAR SE.

&&

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 440 AM EDT WED MAY 22 2013

A SECONDARY UPPER LEVEL TROF WILL MOVE SOUTHEAST ACROSS THE WESTERN
GREAT LAKES REGION THURSDAY AS COOLER AIR SPREADS SOUTHEAST. THE
UPPER LEVEL SUPPORT SHOULD BE SUFFICIENT TO PRODUCE SHOWERS...
ALTHOUGH THERE SHOULD BE A WELL DEFINED NW EDGE/ENDING OF THE
PRECIPITATION GIVEN THE SUBSIDENCE BEHIND THE TROF. PUT SOME DETAIL
IN THE GRIDS IN THIS REGARD THURSDAY WITH THE BEST CHANCE FOR RAIN
EARLY IN THE DAY. ADDED PATCHY FROST NORTHERN AREAS THURSDAY NIGHT.
SKIES SHOULD CLEAR WITH WINDS BECOMING LIGHT MOST AREAS. OTHERWISE...
KEPT THE REST OF THE FORECAST DRY. SPECTRAL MODELS PROVIDING A RANGE
OF HANDLING THE SHORT WAVE ENERGY MOVING EAST AS THE UPPER LEVEL
RIDGE AMPLIFIES OVER THE EASTERN HALF OF THE CONUS. THE ECMWF KEEP
THE ENTIRE PERIOD DRY AND APPEARS REASONABLE WITH THIS SOLUTION.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 116 AM EDT WED MAY 22 2013

VFR CONDITIONS ACROSS THE AREA ATTM WITH SCT SHRA AND
ISOLATED TS. CONVECTION EXPECTED TO BECOME MORE WIDESPREAD OVERNIGHT
AND WED MORNING AS A SHRTWV OVER NW ARK/SW MO LIFTS NE. WK COOL
FRONT MOVG EAST ACROSS NRN INDIANA WED AFTN MAY CAUSE SCT TS MAINLY
OVER NE INDIANA. GENERALLY VFR CONDITIONS EXPECTED TO PERSIST
THROUGH THIS PERIOD EXCEPT DURING CONVECTION WHEN MVFR OR BRIEFLY
LOWER EXPECTED.



&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...GALE WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY EVENING FOR
     LMZ043-046.

&&

$$

SYNOPSIS...JT
SHORT TERM...JT
LONG TERM...SKIPPER
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 220758
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
357 AM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 355 AM EDT WED MAY 22 2013

LOW PRESSURE OVER NORTHEAST IOWA THIS MORNING WILL MOVE EAST
ACROSS SOUTHERN LOWER MICHIGAN TODAY AND TO SOUTHERN ONTARIO
TONIGHT. A WEAK COOL FRONT WILL TRAIL TO THE SOUTH OF THE LOW AND
MOVE EAST ACROSS SOUTHERN MICHIGAN... INDIANA... AND MOST OF OHIO BY
THURSDAY MORNING... WHILE A SECOND STRONGER COLD FRONT DROPS SOUTH
ACROSS THE UPPER GREAT LAKES. SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED ALONG AND AHEAD OF THE FIRST COOL FRONT... WHILE
SCATTERED SHOWERS MAY ACCOMPANY THE SECOND COLD FRONT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

DEEP MIXING TO NEAR 800 MB...SAMPLED BY DTX 18Z SOUNDING...HAS
MIXED DOWN GUSTY WINDS TODAY BETWEEN 15-20 KTS WITH GUSTS AS HIGH
AS 30 KTS. THESE WINDS WILL DIMINISH INTO THE EVENING AS BOUNDARY
LEVEL DECOUPLING COMMENCES. EASTERN AREAS ARE NEARLY CLOUD FREE AS
DEWPOINTS HAVE MIXED INTO THE UPPER 50S TO NEAR 60 WHICH HAS
LIMITED INSTABILITY AND CONSEQUENT CU DEVELOPMENT. EVEN IN WESTERN
AREAS WHERE DEWPOINTS HAVE REMAINED IN THE LOW TO MID 60S...CU
DEVELOPMENT HAS LACKED VERTICAL DEVELOPMENT AS MEAGER MID LEVEL
LAPSE RATES LEFT IN THE WAKE OF MORNING CONVECTION HAVE YET TO
STEEPEN. GIVEN THE LACK OF FORCING AND NEARLY MOIST ADIABATIC
LAPSE RATES FROM THE LCL TO THE TROPOPAUSE...HAVE VERY LITTLE
CONFIDENCE IN ANY DIURNAL SHOWER OR THUNDERSTORM DEVELOPMENT.

CHANCES FOR RAINFALL DURING THE EARLY MORNING HOURS ON WEDNESDAY
LOOK QUITE FAVORABLE AS A STRONG VORT MAX PIVOTS OUT OF OKLAHOMA AND
EJECTS TOWARDS OUR AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD ARRIVE BETWEEN 06 AND 12Z AS MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA. MID-LEVEL HEIGHT PERTURBATION WILL BE
DAMPENING AS IT MOVES ACROSS THE AREA...BUT WITH 500-1000 J/KG OF
CAPE ACROSS THE AREA...INSTABILITY SHOULD BE SUFFICIENT FOR STORMS
TO SUSTAIN THEMSELVES. SHEAR PROFILE WILL ONCE AGAIN REMAIN
FAVORABLE...BUT AFOREMENTIONED WEAKENING FORCING AND INSTABILITY
SHOULD KEEP THE SEVERE THREAT MINIMAL.

BUMPED UP HIGH TEMPERATURES SLIGHTLY ON WEDNESDAY AS BREAKS IN THE
CLOUDS DURING THE MORNING HOURS SHOULD ALLOW TEMPERATURES TO WARM
SLIGHTLY MORE THAN PREVIOUSLY FORECAST...ESPECIALLY IN EASTERN
AREAS.  THERE SHOULD BE A LULL IN THE PRECIPITATION DURING THE
MORNING HOURS AS THE OVERNIGHT WAVE LIFTS NORTH...BUT ADDITIONAL
AFTERNOON DEVELOPMENT IS LIKELY AS BREAKS IN THE CLOUDS ALLOW ENOUGH
SURFACE HEATING FOR INSTABILITY BETWEEN 500 AND 1000 J/KG. SEVERE
WEATHER THREAT DOES EXIST IN EASTERN AREAS IF GREATER
DESTABILIZATION CAN OCCUR...BUT CURRENT THINKING IS THAT THE
GREATEST THREAT WILL BE EAST OF OUR FORECAST AREA.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

CLOSED UPPER LOW OPENING UP AND SHIFTING EASTWARD INTO THE MID MS
VALLEY TO BEGIN THE FORECAST PERIOD. SFC LOW PRESSURE WILL BE IN
EASTERN GREAT LAKES AND ASSOCIATED COLD FRONT EXPECTED TO ALREADY BE
EAST OF THE CWA. UPPER TROF AXIS THEN MOVES THROUGH THE AREA ON
THURSDAY BRINGING LINGERING CHANCES FOR SHOWERS BEFORE SYSTEM
FINALLY EXITS AND MAKES WAY FOR MUCH COOLER CANADIAN HIGH PRESSURE.
SFC HIGH PRESSURE TO DOMINATE THE PATTERN FOR FRI AND SAT WITH MUCH
COOLER BUT NOT TOO UNSEASONABLE WITH M60S AND M40S EXPECTED. SFC
RIDGE AXIS SLIDES EAST OF THE REGION AND NW FLOW PATTERN ALOFT
OFFERS A LOT OF UNCERTAINTY AMONG THE MEDIUM RANGE MODELS BY DAYS
6 AND 7. AGREEMENT EXISTS IN ATTEMPTING TO BRING SHORT WAVE
DISTURBANCE FROM THE PLAINS EASTWARD...BUT VARY IN TIMING AND
RANGE IN LOCATION FROM TN VALLEY TO THE GREAT LAKES REGION. GULF
SUFFICIENTLY CUT OFF BY SFC RIDGE BRINGING AVAILABLE MOISTURE INTO
QUESTION AS WELL. MEAN ENSEMBLE AND EVEN MOST OF THE HIGHER END
MEMBERS STILL RUNNING BELOW CLIMATOLOGY FOR POPS SO STILL LEANING
TOWARD STAYING WITH DRY FORECAST UNTIL BETTER CONSENSUS AND
STRONGER MODEL SIGNAL PRESENTS ITSELF.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 116 AM EDT WED MAY 22 2013

VFR CONDITIONS ACROSS THE AREA ATTM WITH SCT SHRA AND ISOLATED TS.
CONVECTION EXPECTED TO BECOME MORE WIDESPREAD OVERNIGHT AND WED
MORNING AS A SHRTWV OVER NW ARK/SW MO LIFTS NE. WK COOL FRONT MOVG
EAST ACROSS NRN INDIANA WED AFTN MAY CAUSE SCT TS MAINLY OVER NE
INDIANA. GENERALLY VFR CONDITIONS EXPECTED TO PERSIST THROUGH THIS
PERIOD EXCEPT DURING CONVECTION WHEN MVFR OR BRIEFLY LOWER
EXPECTED.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...JT
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 220524
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
124 AM EDT WED MAY 22 2013

.SYNOPSIS...
ISSUED AT 550 PM EDT TUE MAY 21 2013

LOW PRESSURE OVER THE UPPER MIDWEST WILL TRACK EAST INTO THE GREAT
LAKES REGION TOMORROW. THIS SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS TO THE AREA...MAINLY LATER TONIGHT
INTO WEDNESDAY. A FEW THUNDERSTORMS MAY BECOME STRONG TO SEVERE. A
FEW SHOWERS MAY LINGER INTO THURSDAY...WITH COOLER AND DRIER AIR
FORECAST TO SETTLE INTO THE REGION LATE THIS WEEK INTO THE
HOLIDAY WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

DEEP MIXING TO NEAR 800 MB...SAMPLED BY DTX 18Z SOUNDING...HAS
MIXED DOWN GUSTY WINDS TODAY BETWEEN 15-20 KTS WITH GUSTS AS HIGH
AS 30 KTS. THESE WINDS WILL DIMINISH INTO THE EVENING AS BOUNDARY
LEVEL DECOUPLING COMMENCES. EASTERN AREAS ARE NEARLY CLOUD FREE AS
DEWPOINTS HAVE MIXED INTO THE UPPER 50S TO NEAR 60 WHICH HAS
LIMITED INSTABILITY AND CONSEQUENT CU DEVELOPMENT. EVEN IN WESTERN
AREAS WHERE DEWPOINTS HAVE REMAINED IN THE LOW TO MID 60S...CU
DEVELOPMENT HAS LACKED VERTICAL DEVELOPMENT AS MEAGER MID LEVEL
LAPSE RATES LEFT IN THE WAKE OF MORNING CONVECTION HAVE YET TO
STEEPEN. GIVEN THE LACK OF FORCING AND NEARLY MOIST ADIABATIC
LAPSE RATES FROM THE LCL TO THE TROPOPAUSE...HAVE VERY LITTLE
CONFIDENCE IN ANY DIURNAL SHOWER OR THUNDERSTORM DEVELOPMENT.

CHANCES FOR RAINFALL DURING THE EARLY MORNING HOURS ON WEDNESDAY
LOOK QUITE FAVORABLE AS A STRONG VORT MAX PIVOTS OUT OF OKLAHOMA AND
EJECTS TOWARDS OUR AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD ARRIVE BETWEEN 06 AND 12Z AS MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA. MID-LEVEL HEIGHT PERTURBATION WILL BE
DAMPENING AS IT MOVES ACROSS THE AREA...BUT WITH 500-1000 J/KG OF
CAPE ACROSS THE AREA...INSTABILITY SHOULD BE SUFFICIENT FOR STORMS
TO SUSTAIN THEMSELVES. SHEAR PROFILE WILL ONCE AGAIN REMAIN
FAVORABLE...BUT AFOREMENTIONED WEAKENING FORCING AND INSTABILITY
SHOULD KEEP THE SEVERE THREAT MINIMAL.

BUMPED UP HIGH TEMPERATURES SLIGHTLY ON WEDNESDAY AS BREAKS IN THE
CLOUDS DURING THE MORNING HOURS SHOULD ALLOW TEMPERATURES TO WARM
SLIGHTLY MORE THAN PREVIOUSLY FORECAST...ESPECIALLY IN EASTERN
AREAS.  THERE SHOULD BE A LULL IN THE PRECIPITATION DURING THE
MORNING HOURS AS THE OVERNIGHT WAVE LIFTS NORTH...BUT ADDITIONAL
AFTERNOON DEVELOPMENT IS LIKELY AS BREAKS IN THE CLOUDS ALLOW ENOUGH
SURFACE HEATING FOR INSTABILITY BETWEEN 500 AND 1000 J/KG. SEVERE
WEATHER THREAT DOES EXIST IN EASTERN AREAS IF GREATER
DESTABILIZATION CAN OCCUR...BUT CURRENT THINKING IS THAT THE
GREATEST THREAT WILL BE EAST OF OUR FORECAST AREA.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

CLOSED UPPER LOW OPENING UP AND SHIFTING EASTWARD INTO THE MID MS
VALLEY TO BEGIN THE FORECAST PERIOD. SFC LOW PRESSURE WILL BE IN
EASTERN GREAT LAKES AND ASSOCIATED COLD FRONT EXPECTED TO ALREADY BE
EAST OF THE CWA. UPPER TROF AXIS THEN MOVES THROUGH THE AREA ON
THURSDAY BRINGING LINGERING CHANCES FOR SHOWERS BEFORE SYSTEM
FINALLY EXITS AND MAKES WAY FOR MUCH COOLER CANADIAN HIGH PRESSURE.
SFC HIGH PRESSURE TO DOMINATE THE PATTERN FOR FRI AND SAT WITH MUCH
COOLER BUT NOT TOO UNSEASONABLE WITH M60S AND M40S EXPECTED. SFC
RIDGE AXIS SLIDES EAST OF THE REGION AND NW FLOW PATTERN ALOFT
OFFERS A LOT OF UNCERTAINTY AMONG THE MEDIUM RANGE MODELS BY DAYS
6 AND 7. AGREEMENT EXISTS IN ATTEMPTING TO BRING SHORT WAVE
DISTURBANCE FROM THE PLAINS EASTWARD...BUT VARY IN TIMING AND
RANGE IN LOCATION FROM TN VALLEY TO THE GREAT LAKES REGION. GULF
SUFFICIENTLY CUT OFF BY SFC RIDGE BRINGING AVAILABLE MOISTURE INTO
QUESTION AS WELL. MEAN ENSEMBLE AND EVEN MOST OF THE HIGHER END
MEMBERS STILL RUNNING BELOW CLIMATOLOGY FOR POPS SO STILL LEANING
TOWARD STAYING WITH DRY FORECAST UNTIL BETTER CONSENSUS AND
STRONGER MODEL SIGNAL PRESENTS ITSELF.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 116 AM EDT WED MAY 22 2013

VFR CONDITIONS ACROSS THE AREA ATTM WITH SCT SHRA AND ISOLATED TS.
CONVECTION EXPECTED TO BECOME MORE WIDESPREAD OVERNIGHT AND WED
MORNING AS A SHRTWV OVER NW ARK/SW MO LIFTS NE. WK COOL FRONT MOVG
EAST ACROSS NRN INDIANA WED AFTN MAY CAUSE SCT TS MAINLY OVER NE
INDIANA. GENERALLY VFR CONDITIONS EXPECTED TO PERSIST THROUGH THIS
PERIOD EXCEPT DURING CONVECTION WHEN MVFR OR BRIEFLY LOWER
EXPECTED.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...JT


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 220043
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
843 PM EDT TUE MAY 21 2013

.SYNOPSIS...
ISSUED AT 550 PM EDT TUE MAY 21 2013

LOW PRESSURE OVER THE UPPER MIDWEST WILL TRACK EAST INTO THE GREAT
LAKES REGION TOMORROW. THIS SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS TO THE AREA...MAINLY LATER TONIGHT
INTO WEDNESDAY. A FEW THUNDERSTORMS MAY BECOME STRONG TO SEVERE. A
FEW SHOWERS MAY LINGER INTO THURSDAY...WITH COOLER AND DRIER AIR
FORECAST TO SETTLE INTO THE REGION LATE THIS WEEK INTO THE
HOLIDAY WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

DEEP MIXING TO NEAR 800 MB...SAMPLED BY DTX 18Z SOUNDING...HAS
MIXED DOWN GUSTY WINDS TODAY BETWEEN 15-20 KTS WITH GUSTS AS HIGH
AS 30 KTS. THESE WINDS WILL DIMINISH INTO THE EVENING AS BOUNDARY
LEVEL DECOUPLING COMMENCES. EASTERN AREAS ARE NEARLY CLOUD FREE AS
DEWPOINTS HAVE MIXED INTO THE UPPER 50S TO NEAR 60 WHICH HAS
LIMITED INSTABILITY AND CONSEQUENT CU DEVELOPMENT. EVEN IN WESTERN
AREAS WHERE DEWPOINTS HAVE REMAINED IN THE LOW TO MID 60S...CU
DEVELOPMENT HAS LACKED VERTICAL DEVELOPMENT AS MEAGER MID LEVEL
LAPSE RATES LEFT IN THE WAKE OF MORNING CONVECTION HAVE YET TO
STEEPEN. GIVEN THE LACK OF FORCING AND NEARLY MOIST ADIABATIC
LAPSE RATES FROM THE LCL TO THE TROPOPAUSE...HAVE VERY LITTLE
CONFIDENCE IN ANY DIURNAL SHOWER OR THUNDERSTORM DEVELOPMENT.

CHANCES FOR RAINFALL DURING THE EARLY MORNING HOURS ON WEDNESDAY
LOOK QUITE FAVORABLE AS A STRONG VORT MAX PIVOTS OUT OF OKLAHOMA AND
EJECTS TOWARDS OUR AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD ARRIVE BETWEEN 06 AND 12Z AS MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA. MID-LEVEL HEIGHT PERTURBATION WILL BE
DAMPENING AS IT MOVES ACROSS THE AREA...BUT WITH 500-1000 J/KG OF
CAPE ACROSS THE AREA...INSTABILITY SHOULD BE SUFFICIENT FOR STORMS
TO SUSTAIN THEMSELVES. SHEAR PROFILE WILL ONCE AGAIN REMAIN
FAVORABLE...BUT AFOREMENTIONED WEAKENING FORCING AND INSTABILITY
SHOULD KEEP THE SEVERE THREAT MINIMAL.

BUMPED UP HIGH TEMPERATURES SLIGHTLY ON WEDNESDAY AS BREAKS IN THE
CLOUDS DURING THE MORNING HOURS SHOULD ALLOW TEMPERATURES TO WARM
SLIGHTLY MORE THAN PREVIOUSLY FORECAST...ESPECIALLY IN EASTERN
AREAS.  THERE SHOULD BE A LULL IN THE PRECIPITATION DURING THE
MORNING HOURS AS THE OVERNIGHT WAVE LIFTS NORTH...BUT ADDITIONAL
AFTERNOON DEVELOPMENT IS LIKELY AS BREAKS IN THE CLOUDS ALLOW ENOUGH
SURFACE HEATING FOR INSTABILITY BETWEEN 500 AND 1000 J/KG. SEVERE
WEATHER THREAT DOES EXIST IN EASTERN AREAS IF GREATER
DESTABILIZATION CAN OCCUR...BUT CURRENT THINKING IS THAT THE
GREATEST THREAT WILL BE EAST OF OUR FORECAST AREA.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

CLOSED UPPER LOW OPENING UP AND SHIFTING EASTWARD INTO THE MID MS
VALLEY TO BEGIN THE FORECAST PERIOD. SFC LOW PRESSURE WILL BE IN
EASTERN GREAT LAKES AND ASSOCIATED COLD FRONT EXPECTED TO ALREADY BE
EAST OF THE CWA. UPPER TROF AXIS THEN MOVES THROUGH THE AREA ON
THURSDAY BRINGING LINGERING CHANCES FOR SHOWERS BEFORE SYSTEM
FINALLY EXITS AND MAKES WAY FOR MUCH COOLER CANADIAN HIGH PRESSURE.
SFC HIGH PRESSURE TO DOMINATE THE PATTERN FOR FRI AND SAT WITH MUCH
COOLER BUT NOT TOO UNSEASONABLE WITH M60S AND M40S EXPECTED. SFC
RIDGE AXIS SLIDES EAST OF THE REGION AND NW FLOW PATTERN ALOFT
OFFERS A LOT OF UNCERTAINTY AMONG THE MEDIUM RANGE MODELS BY DAYS
6 AND 7. AGREEMENT EXISTS IN ATTEMPTING TO BRING SHORT WAVE
DISTURBANCE FROM THE PLAINS EASTWARD...BUT VARY IN TIMING AND
RANGE IN LOCATION FROM TN VALLEY TO THE GREAT LAKES REGION. GULF
SUFFICIENTLY CUT OFF BY SFC RIDGE BRINGING AVAILABLE MOISTURE INTO
QUESTION AS WELL. MEAN ENSEMBLE AND EVEN MOST OF THE HIGHER END
MEMBERS STILL RUNNING BELOW CLIMATOLOGY FOR POPS SO STILL LEANING
TOWARD STAYING WITH DRY FORECAST UNTIL BETTER CONSENSUS AND
STRONGER MODEL SIGNAL PRESENTS ITSELF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 840 PM EDT TUE MAY 21 2013

ATTEMPT TO TARGET CONDITIONAL CONVECTIVE CHANCES THIS FORECAST
PERIOD. MARGINAL SURFACE BASED INSTABILITY ACROSS NORTHERN INDIANA
WITH ONLY A FEW CELLS BETWEEN KSBN/KFWA THIS EVENING...FAILING TO
SUSTAIN AS WELL SOUTH OF BETTER SBCAPE/EFFECTIVE SHEAR OVERLAP THAT
RESIDES FARTHER NORTH...FROM THE MI THUMB SOUTHWEST TO NEAR KGRR
VCNTY. ISOLATED NOW INTO SOUTHERN LOWER MICHIGAN BARELY MUSTERING
DEPTH FOR GLACIATION/LIGHTNING PRODUCTION AMID WEAK MID LEVEL LAPSE
RATES AROUND 5 C/KM. ONLY SUBSTANTIVE CHANCE WILL BE NEAR DAYBREAK
AS BACKED/RAMPING NOCTURNAL LOW LEVEL JET ASSERTS FROM 40-50KT
SSWRLY FLOW FROM WESTERN TN INTO SOUTHERN INDIANA AROUND 09-12 UTC.
MIDLEVEL SHORTWAVE/SPEEDMAX SUPPORTS UPTICK IN OVERALL UPSTREAM DEEP
LAYER BULK SHEAR PROFILE NECESSARY FOR SUSTENANCE GIVEN GENERALLY
ANEMIC AND DECLINING THERMODYNAMIC PROFILE ACROSS NORTHERN INDIANA
LATE TONIGHT. ATTEMPT TO TARGET 3 HOUR WINDOWS FOR TEMPO TSRA WITH
OVERALL CONDITIONS AOA FUEL ALTERNATE...WITH MUCH LOWER CHANCES THAT
CELL CENTROIDS AND ASSOCD IFR MET CONDITIONS WOULD AFFECT AIRFIELD
DIRECTLY. ANOTHER TIMED CHANCE FOR CONVECTION LATE IN FORECAST
PERIOD AT KFWA IMMEDIATELY AHEAD OF FRONTAL BOUNDARY AND
DIFFERENTIAL CYCLONIC VORTICITY ADVECTION EARLY WED AFTERNOON.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...MURPHY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 212151
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
551 PM EDT TUE MAY 21 2013

.SYNOPSIS...
ISSUED AT 550 PM EDT TUE MAY 21 2013

LOW PRESSURE OVER THE UPPER MIDWEST WILL TRACK EAST INTO THE GREAT
LAKES REGION TOMORROW. THIS SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS TO THE AREA...MAINLY LATER TONIGHT
INTO WEDNESDAY. A FEW THUNDERSTORMS MAY BECOME STRONG TO SEVERE. A
FEW SHOWERS MAY LINGER INTO THURSDAY...WITH COOLER AND DRIER AIR
FORECAST TO SETTLE INTO THE REGION LATE THIS WEEK INTO THE
HOLIDAY WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

DEEP MIXING TO NEAR 800 MB...SAMPLED BY DTX 18Z SOUNDING...HAS
MIXED DOWN GUSTY WINDS TODAY BETWEEN 15-20 KTS WITH GUSTS AS HIGH
AS 30 KTS. THESE WINDS WILL DIMINISH INTO THE EVENING AS BOUNDARY
LEVEL DECOUPLING COMMENCES. EASTERN AREAS ARE NEARLY CLOUD FREE AS
DEWPOINTS HAVE MIXED INTO THE UPPER 50S TO NEAR 60 WHICH HAS
LIMITED INSTABILITY AND CONSEQUENT CU DEVELOPMENT. EVEN IN WESTERN
AREAS WHERE DEWPOINTS HAVE REMAINED IN THE LOW TO MID 60S...CU
DEVELOPMENT HAS LACKED VERTICAL DEVELOPMENT AS MEAGER MID LEVEL
LAPSE RATES LEFT IN THE WAKE OF MORNING CONVECTION HAVE YET TO
STEEPEN. GIVEN THE LACK OF FORCING AND NEARLY MOIST ADIABATIC
LAPSE RATES FROM THE LCL TO THE TROPOPAUSE...HAVE VERY LITTLE
CONFIDENCE IN ANY DIURNAL SHOWER OR THUNDERSTORM DEVELOPMENT.

CHANCES FOR RAINFALL DURING THE EARLY MORNING HOURS ON WEDNESDAY
LOOK QUITE FAVORABLE AS A STRONG VORT MAX PIVOTS OUT OF OKLAHOMA AND
EJECTS TOWARDS OUR AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD ARRIVE BETWEEN 06 AND 12Z AS MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA. MID-LEVEL HEIGHT PERTURBATION WILL BE
DAMPENING AS IT MOVES ACROSS THE AREA...BUT WITH 500-1000 J/KG OF
CAPE ACROSS THE AREA...INSTABILITY SHOULD BE SUFFICIENT FOR STORMS
TO SUSTAIN THEMSELVES. SHEAR PROFILE WILL ONCE AGAIN REMAIN
FAVORABLE...BUT AFOREMENTIONED WEAKENING FORCING AND INSTABILITY
SHOULD KEEP THE SEVERE THREAT MINIMAL.

BUMPED UP HIGH TEMPERATURES SLIGHTLY ON WEDNESDAY AS BREAKS IN THE
CLOUDS DURING THE MORNING HOURS SHOULD ALLOW TEMPERATURES TO WARM
SLIGHTLY MORE THAN PREVIOUSLY FORECAST...ESPECAILLY IN EASTERN
AREAS.  THERE SHOULD BE A LULL IN THE PRECIPITATION DURING THE
MORNING HOURS AS THE OVERNIGHT WAVE LIFTS NORTH...BUT ADDITIONAL
AFTERNOON DEVELOPMENT IS LIKELY AS BREAKS IN THE CLOUDS ALLOW ENOUGH
SURFACE HEATING FOR INSTABILITY BETWEEN 500 AND 1000 J/KG. SEVERE
WEATHER THREAT DOES EXIST IN EASTERN AREAS IF GREATER
DESTABILIZATION CAN OCCUR...BUT CURRENT THINKING IS THAT THE
GREATEST THREAT WILL BE EAST OF OUR FORECAST AREA.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

CLOSED UPPER LOW OPENING UP AND SHIFTING EASTWARD INTO THE MID MS
VALLEY TO BEGIN THE FORECAST PERIOD. SFC LOW PRESSURE WILL BE IN
EASTERN GREAT LAKES AND ASSOCIATED COLD FRONT EXPECTED TO ALREADY BE
EAST OF THE CWA. UPPER TROF AXIS THEN MOVES THROUGH THE AREA ON
THURSDAY BRINGING LINGERING CHANCES FOR SHOWERS BEFORE SYSTEM
FINALLY EXITS AND MAKES WAY FOR MUCH COOLER CANADIAN HIGH PRESSURE.
SFC HIGH PRESSURE TO DOMINATE THE PATTERN FOR FRI AND SAT WITH MUCH
COOLER BUT NOT TOO UNSEASONABLE WITH M60S AND M40S EXPECTED. SFC
RIDGE AXIS SLIDES EAST OF THE REGION AND NW FLOW PATTERN ALOFT
OFFERS ALOT OF UNCERTAINTY AMONG THE MEDIUM RANGE MODELS BY DAYS 6
AND 7. AGREEMENT EXISTS IN ATTEMPTING TO BRING SHORT WAVE
DISTURBANCE FROM THE PLAINS EASTWARD...BUT VARY IN TIMING AND RANGE
IN LOCATION FROM TN VALLEY TO THE GREAT LAKES REGION. GULF
SUFFICIENTLY CUT OFF BY SFC RIDGE BRINGING AVAILABLE MOISTURE INTO
QUESTION AS WELL. MEAN ENSEMBLE AND EVEN MOST OF THE HIGHER END
MEMBERS STILL RUNNING BELOW CLIMATOLOGY FOR POPS SO STILL LEANING
TOWARD STAYING WITH DRY FORECAST UNTIL BETTER CONSENSUS AND STRONGER
MODEL SIGNAL PRESENTS ITSELF.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 136 PM EDT TUE MAY 21 2013

DEEP MIXING TO GREATER THAN 850MB PER RAP/NAM/GFS BUFKIT SOUNDINGS
HAS COMMENCED THIS AFTERNOON RESULTING IN GUSTS AOA 30 KTS BEING
REPORTED ACROSS MOST OF THE AREA. THESE WINDS WILL CONTINUE INTO THE
EARLY EVENING BEFORE WEAKENING NEAR SUNSET. CONVECTIVE CHANCES
REMAIN LOW THROUGHOUT THE DAY TODAY AS AIRMASS STABILIZATION FROM
MORNING CONVECTION SEEMS TO BE WINNING OUT. THUNDERSTORM CHANCES
WILL INCREASE TONIGHT AS VORT MAX ACROSS WESTERN OKLAHOMA AT 18Z
SWINGS UP INTO THE SOUTHERN GREAT LAKES. THE STORMS WILL MOVE INTO
THE AREA AFTER 06Z. IFR OR LOWER CIGS/VIS POSSIBLE WITH THESE
STORMS. LATER TAF ISSUANCES WILL ATTEMPT TO BETTER DISCERN THE
TIMING/IMPACT AT KFWA AND KSBN AS CONVECTIVE EVOLUTION EVOLVES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL/KG
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)

FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA

000
FXUS63 KIWX 211915
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
315 PM EDT TUE MAY 21 2013

.SYNOPSIS...
ISSUED AT 1042 AM EDT TUE MAY 21 2013

LOW PRESSURE OVER THE UPPER MIDWEST WILL TRACK EAST INTO THE GREAT
LAKES REGION TOMORROW. THIS SYSTEM WILL BRING INCREASING CHANCES
FOR SHOWERS AND THUNDERSTORMS TO THE AREA...MAINLY LATER TONIGHT
INTO WEDNESDAY. A FEW THUNDERSTORMS MAY BECOME STRONG TO SEVERE. A
FEW SHOWERS MAY LINGER INTO THURSDAY...WITH COOLER AND DRIER AIR
FORECAST TO SETTLE INTO THE REGION LATE THIS WEEK INTO THE
HOLIDAY WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

DEEP MIXING TO NEAR 800 MB...SAMPLED BY DTX 18Z SOUNDING...HAS
MIXED DOWN GUSTY WINDS TODAY BETWEEN 15-20 KTS WITH GUSTS AS HIGH
AS 30 KTS. THESE WINDS WILL DIMINISH INTO THE EVENING AS BOUNDARY
LEVEL DECOUPLING COMMENCES. EASTERN AREAS ARE NEARLY CLOUD FREE AS
DEWPOINTS HAVE MIXED INTO THE UPPER 50S TO NEAR 60 WHICH HAS
LIMITED INSTABILITY AND CONSEQUENT CU DEVELOPMENT. EVEN IN WESTERN
AREAS WHERE DEWPOINTS HAVE REMAINED IN THE LOW TO MID 60S...CU
DEVELOPMENT HAS LACKED VERTICAL DEVELOPMENT AS MEAGER MID LEVEL
LAPSE RATES LEFT IN THE WAKE OF MORNING CONVECTION HAVE YET TO
STEEPEN. GIVEN THE LACK OF FORCING AND NEARLY MOIST ADIABATIC
LAPSE RATES FROM THE LCL TO THE TROPOPAUSE...HAVE VERY LITTLE
CONFIDENCE IN ANY DIURNAL SHOWER OR THUNDERSTORM DEVELOPMENT.

CHANCES FOR RAINFALL DURING THE EARLY MORNING HOURS ON WEDNESDAY
LOOK QUITE FAVORABLE AS A STRONG VORT MAX PIVOTS OUT OF OKLAHOMA AND
EJECTS TOWARDS OUR AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND
THUNDERSTORMS SHOULD ARRIVE BETWEEN 06 AND 12Z AS MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA. MID-LEVEL HEIGHT PERTURBATION WILL BE
DAMPENING AS IT MOVES ACROSS THE AREA...BUT WITH 500-1000 J/KG OF
CAPE ACROSS THE AREA...INSTABILITY SHOULD BE SUFFICIENT FOR STORMS
TO SUSTAIN THEMSELVES. SHEAR PROFILE WILL ONCE AGAIN REMAIN
FAVORABLE...BUT AFOREMENTIONED WEAKENING FORCING AND INSTABILITY
SHOULD KEEP THE SEVERE THREAT MINIMAL.

BUMPED UP HIGH TEMPERATURES SLIGHTLY ON WEDNESDAY AS BREAKS IN THE
CLOUDS DURING THE MORNING HOURS SHOULD ALLOW TEMPERATURES TO WARM
SLIGHTLY MORE THAN PREVIOUSLY FORECAST...ESPECAILLY IN EASTERN
AREAS.  THERE SHOULD BE A LULL IN THE PRECIPITATION DURING THE
MORNING HOURS AS THE OVERNIGHT WAVE LIFTS NORTH...BUT ADDITIONAL
AFTERNOON DEVELOPMENT IS LIKELY AS BREAKS IN THE CLOUDS ALLOW ENOUGH
SURFACE HEATING FOR INSTABILITY BETWEEN 500 AND 1000 J/KG. SEVERE
WEATHER THREAT DOES EXIST IN EASTERN AREAS IF GREATER
DESTABILIZATION CAN OCCUR...BUT CURRENT THINKING IS THAT THE
GREATEST THREAT WILL BE EAST OF OUR FORECAST AREA.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 PM EDT TUE MAY 21 2013

CLOSED UPPER LOW OPENING UP AND SHIFTING EASTWARD INTO THE MID MS
VALLEY TO BEGIN THE FORECAST PERIOD. SFC LOW PRESSURE WILL BE IN
EASTERN GREAT LAKES AND ASSOCIATED COLD FRONT EXPECTED TO ALREADY BE
EAST OF THE CWA. UPPER TROF AXIS THEN MOVES THROUGH THE AREA ON
THURSDAY BRINGING LINGERING CHANCES FOR SHOWERS BEFORE SYSTEM
FINALLY EXITS AND MAKES WAY FOR MUCH COOLER CANADIAN HIGH PRESSURE.
SFC HIGH PRESSURE TO DOMINATE THE PATTERN FOR FRI AND SAT WITH MUCH
COOLER BUT NOT TOO UNSEASONABLE WITH M60S AND M40S EXPECTED. SFC
RIDGE AXIS SLIDES EAST OF THE REGION AND NW FLOW PATTERN ALOFT
OFFERS ALOT OF UNCERTAINTY AMONG THE MEDIUM RANGE MODELS BY DAYS 6
AND 7. AGREEMENT EXISTS IN ATTEMPTING TO BRING SHORT WAVE
DISTURBANCE FROM THE PLAINS EASTWARD...BUT VARY IN TIMING AND RANGE
IN LOCATION FROM TN VALLEY TO THE GREAT LAKES REGION. GULF
SUFFICIENTLY CUT OFF BY SFC RIDGE BRINGING AVAILABLE MOISTURE INTO
QUESTION AS WELL. MEAN ENSEMBLE AND EVEN MOST OF THE HIGHER END
MEMBERS STILL RUNNING BELOW CLIMATOLOGY FOR POPS SO STILL LEANING
TOWARD STAYING WITH DRY FORECAST UNTIL BETTER CONSENSUS AND STRONGER
MODEL SIGNAL PRESENTS ITSELF.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 136 PM EDT TUE MAY 21 2013

DEEP MIXING TO GREATER THAN 850MB PER RAP/NAM/GFS BUFKIT SOUNDINGS
HAS COMMENCED THIS AFTERNOON RESULTING IN GUSTS AOA 30 KTS BEING
REPORTED ACROSS MOST OF THE AREA. THESE WINDS WILL CONTINUE INTO THE
EARLY EVENING BEFORE WEAKENING NEAR SUNSET. CONVECTIVE CHANCES
REMAIN LOW THROUGHOUT THE DAY TODAY AS AIRMASS STABILIZATION FROM
MORNING CONVECTION SEEMS TO BE WINNING OUT. THUNDERSTORM CHANCES
WILL INCREASE TONIGHT AS VORT MAX ACROSS WESTERN OKLAHOMA AT 18Z
SWINGS UP INTO THE SOUTHERN GREAT LAKES. THE STORMS WILL MOVE INTO
THE AREA AFTER 06Z. IFR OR LOWER CIGS/VIS POSSIBLE WITH THESE
STORMS. LATER TAF ISSUANCES WILL ATTEMPT TO BETTER DISCERN THE
TIMING/IMPACT AT KFWA AND KSBN AS CONVECTIVE EVOLUTION EVOLVES.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&

$$

SYNOPSIS...STEINWEDEL
SHORT TERM...BENTLEY
LONG TERM...JAL
AVIATION...BENTLEY


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