Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 311735
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
135 PM EDT FRI JUL 31 2015

.SYNOPSIS...
ISSUED AT 125 PM EDT FRI JUL 31 2015

ISOLATED SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A PASSING COLD
FRONT WILL CONTINUE THROUGH LATE AFTERNOON...MAINLY ACROSS THE
SOUTH AND EASTERN CWA. HIGHS WILL BE IN THE 80S.

&&

.UPDATE...
ISSUED AT 125 PM EDT FRI JUL 31 2015

WITH INCREASED MOISTURE CONVERGENCE AND MODEST
INSTABILITY...ISOLATED SHOWERS AND THUNDERSTORMS POPPED UP AROUND
1 PM EDT WITHIN A LINE OF CU AHEAD OF THE APPROACHING COLD FRONT.
EXPECT ADDITIONAL SHOWERS AND THUNDERSTORMS TO DEVELOP THIS
AFTERNOON AS THE FRONT PROGRESSES EASTWARD...MAINLY SOUTH OF
US-30. GUSTY WESTERLY WINDS WILL VEER MORE NORTHWEST AS THE FRONT
PASSES. THESE MODEST ONSHORE WINDS LED TO WAVE HEIGHTS OF 2 TO 3
FEET ON LAKE MICHIGAN IN NORTHERN BERRIEN COUNTY. UPGRADED THE
SWIM RISK TO MODERATE ACCORDINGLY GIVEN THAT WINDS/WAVES WILL
CONTINUE THROUGH AT LEAST THE EVENING.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM EDT FRI JUL 31 2015

DIFFICULT NR TERM OWING TO SEWD AMPLIFICATION OF
SEASONABLY STG SW OVR SWRN ONTARIO AS ATTENDANT SFC TROUGH CROSSES
THE SRN LAKES THIS AFTN. NARROW LL THETA-E RIDGING NOTED UPSTREAM IN
00Z RAOBS AND XPCD TO ADVT E/NE INTO THE AREA BY THIS AFTN. HWVR SIG
DIFFS NOTED AMG EVEN SHRT TERM GUIDANCE W/DEGREE OF BNDRY LYR
MOISTENING AND/OR DRYING THAT TAKES PLACE INTO THIS AFTN AND AS SUCH
WHETHER OR NOT CONVN INITIATES OR NOT IN AN OTRWS FVRBL SYNOPTIC
ENVIRONMENT AS DECENT HGT FALLS OVERSPREAD FNTL ZONE THIS AFTN.
REGARDLESS GIVEN OBSVD SFC CONDS UPSTREAM YDA WITHIN WELL MIXED
BNDRY LYR AND GENERAL WIDESPREAD UPR 50 TDS...CONSERVATIVE SFC BASED
CAPES SHLD APCH 1000 J/KG ACRS NRN IN/NW OH PRIOR TO FROPA AND WILL
ENTERTAIN USUALLY SUPERIOR 4KM SPC WRF IN NOTCHING A SWATH OF HIGHER
POPS MID-LT AFTN SOUTH OF HIGHWAY 6 ESP SW/SRN THIRD IN PROXIMITY TO
HIGHER XPCD LL THETA-E RTN.

&&

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 AM EDT FRI JUL 31 2015

THIS PERIOD WILL FEATURE A SOMEWHAT ACTIVE NORTHWEST FLOW REGIME
UNDER A QUASI-STATIONARY HUDSON BAY UPPER LOW THAT WILL SLOWLY PIVOT
SOUTHEAST. NUMEROUS SMALLER SCALE SHORTWAVES EMBEDDED IN THIS
CYCLONIC FLOW WILL SUPPORT SHOWER/STORM CHANCES FOR THE SECOND HALF
OF THE WEEKEND INTO MUCH OF NEXT WEEK...WITH TEMPERATURES TRENDING
BELOW NORMAL. AS EXPECTED MODELS STRUGGLING WITH THE
TIMING/AMPLITUDE OF THESE SMALLER SCALE FEATURES MAKING POPS A LOW
CONFIDENCE FCST IN ANY ONE PERIOD. MODELS CONTINUE TO KEY IN ON
LATER SATURDAY NIGHT/SUNDAY WITH INITIAL LOW LEVEL WAA
SURGE/CONVECTIVELY AIDED WAVE...AND LATER SUNDAY NIGHT/EARLY MONDAY
WITH A STRONGER SHORTWAVE TROUGH/CDFNT ROTATING THROUGH THE GREAT
LAKES FOR BEST SHOWER/STORM CHANCES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 125 PM EDT FRI JUL 31 2015

FORECAST STILL LOOKING ON TRACK FOR VFR CONDITIONS
THROUGH THE TAF PERIOD. COLD FRONT PASSAGE WILL BE THE MAIN STORY
TODAY...WITH WEST-SOUTHWEST WINDS BECOMING MORE NORTHWESTERLY BY
LATE AFTERNOON. AT THIS POINT...ISOLATED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE ALONG AND AHEAD OF THE FRONT THIS AFTERNOON. KFWA STILL
HAS THE BEST SHOT AT SEEING SOME PRECIPITATION...SO INCLUDED VCTS
AROUND 20Z WHEN FRONT MOVES THROUGH. AS OF 1720Z...THERE WAS A SCT-
BKN LINE OF CU ALONG THE FRONT EXTENDING FROM KSBN SOUTHWESTWARD TO
UNION HILL ILLINOIS...WITH DEVELOPING SHOWERS/THUNDERSTORMS ALONG IT
NEAR MARSHALL/STARKE COUNTIES. COULD SEE BRIEF MVFR CONDITIONS IN
HEAVIER SHOWER/TS IF ONE REACHES KFWA.


&&

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

$$

UPDATE...MCD
SYNOPSIS...MCD
SHORT TERM...T
LONG TERM...STEINWEDEL
AVIATION...MCD


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