Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 251450
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1050 AM EDT TUE AUG 25 2015

.SYNOPSIS...
ISSUED AT 1030 AM EDT TUE AUG 25 2015

LINGERING CLOUDS ASSOCIATED WITH A DEEP LOW PRESSURE AREA WILL
PERSIST THROUGH THE REST OF TODAY INTO TONIGHT. A FEW SPRINKLES OR
LIGHT SHOWERS ARE POSSIBLE...ESPECIALLY OVER NORTHERN AREAS
INCLUDING FAR SOUTHERN LOWER MICHIGAN. HIGHS THIS AFTERNOON WILL
BE FROM 65 TO 70. LOWS TONIGHT SHOULD BE FROM 50 TO 55. HIGHS
WEDNESDAY SHOULD BE AROUND 70.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EDT TUE AUG 25 2015

UNSEASONABLY NEGATIVE HEIGHT ANOMALY OVER THE NORTHERN GREAT LAKES
WILL SLOWLY ROTATE EASTWARD THROUGH THE SHORT TERM PERIOD. SUBTLE
VORT MAX CURRENTLY ROTATING TO THE EAST JUST NORTH OF THE LOCAL
FORECAST AREA. LAKE SFC-850MB DELTA T VALUES NEAR 16C HELPING TO
PRODUCE WEAK -SHRA RETURNS ACROSS SW LWR MI. WILL CONTINUE WITH ISO
RW-/SCT SPRINKLES ACROSS THE NORTHERN PORTION OF THE FCST AREA
THROUGH 12Z. TRENDED DOWN POPS A BIT AFTER 12Z AS VORT LOBE EXITS
EAST OF THE AREA AND 850 MB TEMPS SLOWLY WARM W/ A MORE BACKED WRLY
FLOW OFF OF THE LAKE.

ANOTHER VORT MAX WILL ROTATE SE ACROSS LAKE MI LATE TUESDAY
AFTERNOON INTO THE EVENING...COINCIDENT W/ LAKE AGGREGATE SFC TROF.
AS THIS FEATURE PUSHES INLAND ACROSS THE FCST AREA AROUND/AFTER
06Z...INCREASED POPS SLIGHTLY...ESPECIALLY NORTHWEST...AS FLOW VEERS
MORE NNW AND DELTA T VALUES HOVER NEAR 13C W/ BETTER BOUNDARY LAYER
MOISTURE RELATIVE TO THE PREVIOUS 12-18 HOURS. ANY QPF AMOUNTS WILL
BE FAIRLY LIGHT IF ANYTHING THROUGH THE SHORT TERM PERIOD. AS FAR AS
TEMPS GO...BUMPED HIGHS DOWN ON TUESDAY A DEGREE OR SO...ESPECIALLY
NORTH. BUMPED UP LOW TEMPS A DEGREE OR TWO TUESDAY
NIGHT...ESPECIALLY ACROSS THE WEST...AS A RESULT OF EXPECTED
INCREASED CLOUD COVER/LAKE SHADOW DUE TO A MORE NORTHERLY FLOW
REGIME.

&&

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 409 AM EDT TUE AUG 25 2015

PESKY UPPER LOW WILL BE DRIFTING AWAY FROM THE UPPER GREAT LAKES
WEDNESDAY. ONE LAST SHORT WAVE AND WEAK SFC TROUGH WILL BE
SWINGING THROUGH ON BACKSIDE EARLY WEDNESDAY. HIRES MODELS
CONTINUE TO INDICATE SOME SHOWERS ASSOCIATED WITH THIS FEATURE IN
COMBINATION WITH MARGINAL LAKE INSTABILITY AND MOISTURE. HAVE
ADJUSTED POPS WEDNESDAY MORNING TO BETTER REFLECT LATEST GUIDANCE
TRAJECTORIES AND PLACEMENT OF POSSIBLE SHOWER ACTIVITY.

HIGH PRESSURE SLIDES ACROSS THE REGION WEDNESDAY NIGHT INTO FRIDAY
WITH DRY WEATHER AND SLOW WARMING TREND EXPECTED. NEXT CHANCE FOR
PRECIPITATION STILL LOOKS TO BE TOWARD FRIDAY NIGHT INTO THE WEEKEND
WITH SHORT WAVE ORIGINATING FROM MONSOONAL MOISTURE IN THE
SOUTHWEST. THIS FEATURE COULD PROVE INTERESTING FOR OUR AREA DURING
THE LATTER HALF OF THE WEEKEND INTO EARLY NEXT WEEK. MODELS HAVE
BEEN TRENDING TOWARD SLOWING THIS FEATURE AS IT APPROACHES AND
WASHING IT OUT AS IT ENCOUNTERS RIDGING TO OUR EAST. THE PROBLEM IS
THAT A WEAK RESIDUAL UPPER CIRCULATION MAY REMAIN WHICH COULD
PROMOTE SOME AFTERNOON CONVECTION GIVEN BUILDING HEAT AND MOISTURE.
FOR NOW HAVE KEPT THE SUNDAY INTO MONDAY PERIOD DRY BUT WOULD NOT BE
SURPRISED TO SEE THE ADDITION OF SOME POPS IN LATER FORECAST
ITERATIONS IF THIS WEAK FEATURE LINGERS IN THE AREA.

TEMPS WILL BEGIN BELOW NORMAL WITH HIGHS IN THE LOW TO MID 70S AND
LOWS IN THE 50S THROUGH THURSDAY. TEMPS WILL CREEP INTO UPPER 70S
FRIDAY AND THEN BACK ABOVE NORMAL WITH 80S FOR THE WEEKEND AND EARLY
NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 536 AM EDT TUE AUG 25 2015

UPPER LOW ACROSS THE NORTHERN GREAT LAKES WILL KEEP A VFR STRATO-
CU DECK ENTRENCHED ACROSS THE TERMINALS THROUGH MUCH OF THE TAF
PD. A LIGHT -SHRA IS POSSIBLE AT KSBN THROUGH THE TAF PD...HOWEVER
CONFIDENCE/COVERAGE/IMPACT TO LOW TO INCLUDE IN TAF AT THIS TIME.
WINDS WILL GENERALLY BE OUT OF THE W/NW THROUGH THE PERIOD...WITH
A SLIGHT DIURNAL INCREASE IN SPEED THROUGH THE DAYLIGHT HOURS.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT UNTIL 7 PM CDT THIS EVENING FOR INZ003.

MI...BEACH HAZARDS STATEMENT UNTIL 8 PM EDT THIS EVENING FOR MIZ077.

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

&&

$$

SYNOPSIS...SKIPPER
SHORT TERM...NG
LONG TERM...LASHLEY
AVIATION...NG


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