Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 250027
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
827 PM EDT MON AUG 24 2015

.SYNOPSIS...
ISSUED AT 825 PM EDT MON AUG 24 2015

A STRONG LOW PRESSURE SYSTEM OVER SOUTHERN ONTARIO WILL MOVE
SLOWLY EAST OVER THE NEXT COUPLE RESULTING IN UNSEASONABLY COOL
TEMPERATURES ACROSS OUR AREA WITH LOWS TONIGHT IN THE LOWER AND
MIDDLE 50S AND HIGHS TUESDAY IN THE UPPER 60S TO AROUND 70. THERE
IS A SLIGHT CHANCE OF LIGHT SHOWERS OVER SOUTHERN MICHIGAN TONIGHT
INTO TUESDAY MORNING DUE TO A COMBINATION OF THE COLD AIR FLOW
ACROSS THE RELATIVELY WARM WATERS OF LAKE MICHIGAN AND WEAK UPPER
LEVEL DISTURBANCES ROTATING AROUND THE ONTARIO LOW.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 352 PM EDT MON AUG 24 2015

DEEP CUT-OFF LOW OVER SRN ONTARIO WILL MOVE SLOWLY EAST DURING
THE SHORT TERM PERIOD. STRATO CU ASSOCIATED WITH VORT LOBE AND LOW
LEVEL MOISTURE WRAPPING AROUND THIS SYSTEM SHOULD OVERSPREAD NRN
ZONES LATE THIS AFTN WITH SCT-BKN LOW CLOUDS EXPECTED OVER THE
REST OF THE CWA OVERNIGHT. SOME LAKE ENHANCED SHOWERS PSBL TONIGHT
AS LOW LEVEL FLOW VEERS TO 300 DEGREES AND INVERSION RISES INTO
THE 6-9KFT RANGE WITH DELTA T`S IN THE MID TEENS. LAKE EFFECT
SHOWERS REMAIN PSBL TUESDAY ESPECIALLY IN THE MORNING WITH
INVERSION LOWERING IN THE AFTN REDUCING CHANCES. ELSEWHERE IN THE
AREA... COLDER TEMPS ALOFT AND GREATER LEVEL MOISTURE THAN TODAY
SHOULD RESULT IN A BKN CU DECK MUCH OF THE DAY...ESPECIALLY
DOWNWIND OF LAKE MICHIGAN. FOLLOWED MODEL CONSENSUS FOR TEMPS WITH
FCST LOWS IN THE L-M50S TONIGHT AND HIGHS TUESDAY IN THE
U60S/L70S.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 352 PM EDT MON AUG 24 2015

THE UPPER LOW SHOULD HAVE DRIFTED NORTH TO NEAR JAMES BAY BY LATE
TUESDAY. THE GFS APPEARS ON TRACK WITH THIS SYSTEM WITH ISENTROPIC
MID LEVELS/305K SURFACE SHOWING VERY LITTLE TO SUPPORT SYNOPTIC
PRECIPITATION. ALSO...GFS BUFKIT SHOWS WEAK SUBSIDENCE AND
SIGNIFICANT DRYING ABOVE 800 MB...FROM EARLY WEDNESDAY INTO
THURSDAY. HOWEVER...DELTA T VALUES SHOULD BE AROUND 14C AND SHOULD
SUPPORT A CHANCE FOR SHOWERS FROM TUESDAY NIGHT INTO WEDNESDAY
MORNING. INVERSION HEIGHTS SHOULD FALL ENOUGH BY WEDNESDAY AFTERNOON
TO END CHANCES FOR RAIN...SO HAVE ADJUSTED TIMING AND COVERAGE OF
SHOWERS ACCORDINGLY. CHILLY NIGHTS ARE EXPECTED TUESDAY NIGHT AND
WEDNESDAY NIGHT GIVEN A COOL AND DRY AIRMASS WITH CLEAR SKIES AND
LIGHT WINDS. FAVORED THE COOLER GFS LOWS AROUND 50 TO THE LOWER 50S.

FOR THE REST OF THE PERIOD...A WEAK UPPER LEVEL SYSTEM SHOULD EJECT
NORTHEAST AS AN UPPER LEVEL RIDGE BUILDS INTO THE MIDWEST EARLY NEXT
WEEK. KEPT A LOW CHANCE FOR SHOWERS AND STORMS WITH THIS SYSTEM
FRIDAY NIGHT INTO SATURDAY NIGHT. TEMPERATURES SHOULD RISE ABOVE
NORMAL MONDAY AS THE UPPER LEVEL RIDGE BUILDS INTO THE AREA.


&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 822 PM EDT MON AUG 24 2015

VFR CONDS THROUGH THE PD. HIGH BASED STRATOCU FIELD TO INCREASE
AS SHORTWAVE ROTATES THROUGH SRN END OF PRIMARY/NORTHERN UPPER
GREAT LAKES LOW CENTER. ISOLD LIGHT SHRA ASSOCD WITH MODEST LAKE
INDUCED INSTABILITY SHOULD REMAIN WELL NORTH OF KSBN AIRFIELD
OVERNIGHT/TUE AM. OTHERWISE DETAIL PROVIDED FOR WIND SPEED/DIR
WITH SIG LESSER INCREASE IN SPEED/GUSTS TMRW WITH LOWER SFC BASED
LAPSE RATES.

&&

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

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

OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR LMZ043-046.

&&

$$

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


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