Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 291713
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
113 PM EDT TUE JUL 29 2014

.SYNOPSIS...
ISSUED AT 1103 AM EDT TUE JUL 29 2014

PARTLY CLOUDY SKIES ACROSS THE REGION TODAY AND TONIGHT. AN UPPER
LEVEL DISTURBANCE WILL MOVE THROUGH THIS AFTERNOON POSSIBLY
GENERATING SOME SHOWERS AND THUNDERSTORMS. HIGH TEMPERATURES TODAY
WILL RANGE FROM THE LOWER 70S IN WESTERN OHIO TO THE UPPER 70S IN
WESTERN INDIANA. LOW TEMPERATURES TONIGHT WILL BE IN THE MIDDLE
50S ACROSS THE REGION.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 442 AM EDT TUE JUL 29 2014

WV IMAGERY INDICATING COUPLE UPSTREAM SHORTWAVE TO DROP SSEWD
THROUGH THE WESTERN GREAT LAKES. TIMING OF MOST SIGNIFICANT
IMPULSE TO REACH NWRN CWA ABOUT 18-19 UTC. SOUTHERN PERIPHERY OF
5H COLD POOL SETTLES ACROSS NORTHERN CWA WITH M16-17C...PROVIDING
IMPRESSIVE UPPER 30S TO NEAR 40C SURFACE/5H DIFFERENTIALS.
MODIFIED NAM12/RUC POINT SOUNDINGS WITH LOWER 70S/ABOUT 53F
CONSISTENTLY YIELDS 500-750 J/KG. NOTABLY SMALL DIFFERENCE BETWEEN
LCL TO LFC SHOULD PROMOTE AT LEAST MODERATE VERTICAL CU
DEVELOPMENT BY MIDDAY. INITIALLY SOME CONCERN THAT BULK LOW LEVEL
MOISTURE LACKING...THOUGH AMDAR SOUNDINGS INDICATE SOME LAYER
MOISTURE WITHIN 850-740MB. LOW POPS RAMPING BY MIDDAY WITH HIGHEST
NORTHEAST CWA COINCIDENT WITH GREATER INSTABILITY/REMOVED FROM
COOLER LAKE MODIFIED ENVIRONMENT PLUS TIMING OF SHORTWAVE AND
CONVERGENT SIGNATURE IN LOWEST 100 MB. ALSO OPTED FOR COVERAGE
TYPE WORDING IN THIS AREA AS WELL. LOW/8.5-9KFT WET BULB ZERO
HEIGHTS AND OVERALL COLD PROFILE COULD LEAD TO SMALL HAIL
PRODUCTION ASSOCD WITH STRONGEST UPDRAFTS. CONVECTION HIGHLY TIED
TO DIURNAL HEAT CYCLE WITH LITTLE MORE THAN DECAYING SHOWERS
TOWARD/AFTER SUNSET...MAINLY INTO NWRN CWA/POSSIBLE SE EXTENSION
OF STRONGER SBCAPE CENTERED ACROSS EASTERN WI. SLIGHT DOWNWARD
NUDGE TO TEMPS TODAY ESPECIALLY ACROSS NWRN OHIO MORE PROXIMAL TO
925MB THERMAL TROF.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 442 AM EDT TUE JUL 29 2014

AN UPPER LEVEL RIDGE WILL REMAIN UPSTREAM OVER NORTH AMERICA...WITH
TROFFING DOWNSTREAM FROM HUDSON BAY INTO THE WESTERN GREAT LAKES
REGION. HAVE ADDED A CHANCE FOR SHOWERS AND ISOLATED/SCATTERED
THUNDERSTORMS WEDNESDAY AFTERNOON. VERY COOL AIR ALOFT WILL SUPPORT
CAPE VALUES AS HIGH AS 500 TO 1000 J/KG DURING THE AFTERNOON. THERE
WILL BE OPTIMUM LOW WET BULB ZERO HEIGHTS FOR HAIL...SO EXPECT SMALL
HAIL IS VERY POSSIBLE. FOR THE REST OF THE PERIOD...THE GFS AND
CANADIAN ANALOGS BOTH SUPPORT A PERSISTENT PATTERN WITH A NEGATIVE
HEIGHT ANOMALY LINGERING OVER THE WESTERN GREAT LAKES REGION INTO
EARLY NEXT WEEK. THE GFS/ECMWF 850 MB FORECAST TEMPERATURES FAVOR
THE COOLER GFS/MEAN MEX NUMBERS...SO HAVE FORECAST BELOW THE
OPERATIONAL GFS RUN. ADDED A CHANCE FOR SHOWERS AND STORMS SATURDAY
GIVEN GFS/ECMWF/GEM MODEL CONSENSUS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 109 PM EDT TUE JUL 29 2014

CU HAVE BEEN A BIT SLOW TO DEVELOP THUS FAR WITH BAND OF MID
CLOUDS PASSING OVERHEAD THIS MORNING HOLDING TEMPS DOWN A BIT. AS
THEY LEAVE...CONVECTIVE TEMPERATURE SHOULD BE MET AND SCT TO MAYBE
BROKEN VFR BASED CU SHOULD DEVELOP...ESPECIALLY TOWARDS KFWA. LAKE
BREEZE/SHADOW WAS ALMOST TO KSBN WITH WIND SHIFT ALREADY
OCCURRING. CLOUD COVER SHOULD BE RATHER ISOLATED AT THE AIRPORT
WITH THE MORE STABLE AIRMASS FROM THIS FEATURE SO HAVE BACKED OFF
ON SKY COVER. BIT OF MIXING ALSO OCCURRING RESULTING IN SOME WIND
GUSTS IN THE 15 TO NEAR 20 KT RANGE AT KSBN. A STRAY SHOWER IS
POSSIBLE AT KFWA SO WILL LEAVE VCSH MENTION IN.

CIRRUS WILL MOVE OVER TONIGHT AND INTO WEDNESDAY. MAY BE SOME
ADDITIONAL CU AROUND AS YET ANOTHER SYSTEM DROPPING INTO THE
REGION.

&&

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

$$

SYNOPSIS...LOTHAMER
SHORT TERM...MURPHY
LONG TERM...SKIPPER
AVIATION...FISHER


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