Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 290846
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
446 AM EDT TUE JUL 29 2014

.SYNOPSIS...
ISSUED AT 443 AM EDT TUE JUL 29 2014

COOLER AND LESS HUMID CONDITIONS WILL PREVAIL THROUGH MUCH OF THE
WEEK AS LOW PRESSURE REMAINS NORTH OF THE REGION. THERE IS A
SMALL CHANCE FOR SHOWERS AND POSSIBLY EVEN A RUMBLE OF THUNDER
THIS AFTERNOON AND WEDNESDAY AFTERNOON AS WEAK DISTURBANCES WITH
COLD AIR ALOFT MOVE THROUGH THE REGION. HIGHS ON TDAY WILL CLIMB
BACK INTO THE LOWER TO MIDDLE 70S. LOWS TONIGHT WILL GENERALLY BE
IN THE MIDDLE 50S.

&&

.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 143 AM EDT TUE JUL 29 2014

VFR CONDITIONS EXPECTED TO PERSIST THROUGH THIS FORECAST PERIOD.
UPSTREAM IMPULSE COMBINED WITH EXTREMELY COLD MID TROPOSPHERIC
PROFILES SHOULD EASILY GENERATE CU FIELD COINCIDENT WITH MID/LATE
AM SURFACE HEATING. PRESENCE OF MOISTURE PER AMDAR SOUNDINGS IN
850-740MB LAYER AS WELL AS DEGREE OF SURFACE TO 5H THERMAL
DIFFERENTIALS SUGGEST EVEN POTENTIAL FOR SCT SHRA/ISOLD TSRA WITH
PEAK HEATING. AT PRESENT HAVE ONLY ADDED MENTION VCSH TO KFWA PER
TIMING OF IMPULSE AND SLIGHTLY GREATER INSTABILITY/LOW LEVEL
CONVERGENCE SIGNALS PRESENTING WELL INLAND OF LAKE MICHIGAN.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT UNTIL 4 AM CDT EARLY THIS MORNING FOR
     INZ003.

MI...BEACH HAZARDS STATEMENT UNTIL 5 AM EDT EARLY THIS MORNING FOR
     MIZ077.

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
     LMZ043-046.

&&

$$

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


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