Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 301748
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
148 PM EDT TUE SEP 30 2014

.SYNOPSIS...
ISSUED AT 144 PM EDT TUE SEP 30 2014

COOL AND CLOUDY CONDITIONS WILL CONTINUE ACROSS THE REGION THROUGH
TUESDAY NIGHT. DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES ARE
EXPECTED WEDNESDAY AND WEDNESDAY NIGHT. ABOVE NORMAL TEMPERATURES
ARE EXPECTED DURING THE DAY ON THURSDAY...BEFORE SHOWER AND
THUNDERSTORMS CHANCES RETURN TO THE AREA THURSDAY AFTERNOON INTO
FRIDAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM EDT TUE SEP 30 2014

CLOSING OFF UPR LOW WAS MOVG SE INTO THE LWR GRTLKS THIS MORNING
WITH AN ASSOCIATED SFC CDFNT MOVG ACROSS SE PORTION OF CWA.
SHOWERS ASSOCIATED WITH THIS SYSTEM WERE PRIMARILY CONFINED TO THE NE
PORTION OF THE CWA AND SHOULD TAPER OFF/MOVE OUT OF THE AREA THIS
MORNING. EXTENSIVE POST-FRONTAL LOW CLOUD SHIELD SHOULD PERSIST
THROUGH THE MORNING BUT WITH LOW LEVEL FLOW BECOMING ANTICYCLONIC
THIS AFTN AS RIDGE BUILDS SE INTO WI/MI... EXPECT PARTIAL SUNSHINE
LATER TODAY. LOW LEVELS WERE WELL MIXED BEHIND THE FRONT SO NOT
MUCH OF A RECOVERY IN TEMPS EXPECTED TODAY, BUT WILL COUNT ON SOME
INSOLATION THIS AFTN TO BOOST TEMPS A BIT... INTO THE L-M60S OVER
MOST OF THE AREA.

UPR LOW WILL MOVE TO THE MID ATLANTIC COAST TONIGHT WITH DEEP LAYER
RIDGING FOLLOWING IT THE GRTLKS/OH VALLEY. SOME LOW CLOUDS TRAPPED
BENEATH SUBSIDENCE INVERSION ARE EXPECTED TO PERSIST IN OUR
AREA... ESPECIALLY NE PORTIONS OVERNIGHT. THIS SHOULD LIMIT
RADIATIONAL COOLING WITH LOWS FCST MAINLY IN THE M40S. IF SKIES DO
CLEAR... FOG COULD BE A PROBLEM... THOUGH FELT POTENTIAL TOO SMALL TO
MENTION IN FCSTS ATTM.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 342 AM EDT TUE SEP 30 2014

UPPER RIDGE AXIS WILL CENTER OVER THE REGION WEDNESDAY INTO
WEDNESDAY EVENING ENSURING A CONTINUATION OF DRY/FAIR WEATHER TO
START THE PERIOD. SHOULD SEE ANY LOW BKN/OVC STRATOCU MIX OUT BY
LATE MORNING/EARLY AFTERNOON WEDNESDAY GIVEN STRENGTHENING
SUBSIDENCE AND DIURNAL MIXING...WHICH SHOULD ALLOW HIGHS TO MAKE A
RUN AT THE UPPER 60S/LOW 70S. THURSDAY WILL FEATURE INCREASING
CLOUDS AND WARMER TEMPS AS SOUTHERLY FLOW STRENGTHENS IN ADVANCE OF
A WESTERN CONUS LONGWAVE TROUGH. SHOWER CHANCES INCREASE WITH TIME
INTO WESTERN PORTIONS INVOF A POTENTIAL WEAK PRE-FRONTAL FEATURE IN
THETA-E ADV REGIME...ALTHOUGH HELD SHY OF LIKELY POPS AS BETTER
MOISTURE CONVERGENCE/FORCING INITIALLY FOCUSES WEST OF THE IWX CWA.

EXCELLENT MODEL AGREEMENT REMAINS IN ABRUPT FLIP TO COOLER/UNSETTLED
WX UNDER AN AMPLIFYING EASTERN NOAM MEAN TROUGH FRIDAY INTO THE
WEEKEND. EXPECTED PHASING OF EMBEDDED SHORTWAVE ENERGY...WITH
ASSOCIATED DEEPENING SFC CYCLONE TRACK NE THROUGH THE NRN
LAKES/ONTARIO...WILL FORCE A STRONG COLD FRONT EAST THROUGH THE
LOCAL AREA THURSDAY NIGHT/FRIDAY MORNING. RAIN/EMBEDDED THUNDER
CHANCES LOOKING GOOD WITH FROPA GIVEN AMPLE MOISTURE RETURN AND DEEP
ASCENT PLUME WITH SHORTWAVE TROUGH AXIS TAKING ON A NEGATIVE TILT.
CONSIDERED A POP BUMP INTO CATEGORICAL BUT HELD OFF FOR NOW GIVEN
NORMAL TIMING DIFFERENCES AND SLIGHT CONCERN FOR MID MS VALLEY
CONVECTION TO HINDER MOISTURE TRANSPORT. STRONG COLD ADVECTION
EXPECTED FRIDAY INTO FRIDAY NIGHT WITH BEST CHANCE FOR AFTN/EVE
SHOWERS ACROSS NORTHERN PORTIONS NEAR VORT MAX/WRAP AROUND
MOISTURE...AND ADDED SUPPORT FROM LAKE MI AS LAKE-7H DIFFERENTIALS
PLUMMET INTO THE UPPER 20S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 145 PM EDT TUE SEP 30 2014

EXTENSIVE AREA OF LOW CLOUDS PERSISTING OVER MUCH OF THE AREA THIS
AFTERNOON. SOME CLEARING TO THE SOUTH AND WEST OF SBN AND FWA AS MID
LEVEL DRYING ALLOWING FOR SOME MIXING OUT. MAY REALIZE A LITTLE OF
THIS BY LATE THIS AFTERNOON AT THE TAF SITES BUT EXPECT CLOUDS TO
FILL BACK IN OVERNIGHT WITH AMPLE LOW LEVEL MOISTURE IN LIGHT NE
FLOW. MAY SEE SOME PATCHY FOG DEVELOPING OVERNIGHT BUT UNCERTAINTY
EXISTS IN GETTING SUFFICIENT RADIATIONAL COOLING WITH CLOUD COVER SO
WILL LEAVE AS MVFR FOR NOW. SURFACE HIGH PRESSURE BUILDS INTO THE
GREAT LAKES REGION ON WEDNESDAY RESULTING IN VFR CONDITIONS BY MID
MORNING WITH LIGHT EASTERLY FLOW.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.

&&

$$

SYNOPSIS...NG
SHORT TERM...JT
LONG TERM...STEINWEDEL
AVIATION...JAL


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