Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 292003
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
403 PM EDT SAT AUG 29 2015

.SYNOPSIS...
ISSUED AT 359 PM EDT SAT AUG 29 2015

A WEAKENING TROUGH WILL CROSS OVER THE REGION TONIGHT AND SUNDAY.
SCATTERED TO NUMEROUS RAIN SHOWERS ARE EXPECTED OVERNIGHT...WITH
ISOLATED THUNDERSTORMS POSSIBLE IN THE EVENING. OTHERWISE...AREAS
OF FOG ARE POSSIBLE LATER TONIGHT AND SUNDAY MORNING. LOWS WILL
BE IN THE 60S. THERE IS AN ADDITIONAL CHANCE FOR SHOWERS AND
THUNDERSTORMS SUNDAY AFTERNOON. HIGHS WILL BE IN THE 70S AND LOW
80S ON SUNDAY...COOLEST NEAR LAKE MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 359 PM EDT SAT AUG 29 2015

MAIN FOCUS OF THE SHORT TERM IS PRECIPITATION CHANCES TONIGHT AND
SUNDAY...WITH POTENTIAL FOR FOG DEVELOPMENT LATE TONIGHT.

THE UPPER LEVEL DIVERGENCE ASSOCIATED WITH A 300MB JET STREAK THAT
HELPED SUSTAIN PRECIPITATION IN THE NORTH/NORTHWEST EARLIER TODAY
WILL MOVE INTO OUR EASTERN/CENTRAL CWA THIS EVENING....THOUGH IT
WILL GRADUALLY WEAKEN IN INTENSITY. THE VORT MAX ASSOCIATED WITH THE
500MB TROUGH IS SITUATED OVER OUR NORTHWEST NOW...AND WILL GRADUALLY
SHIFT EASTWARD UNTIL IT DISSIPATES SUNDAY MORNING. DEEPEST MOISTURE
ALSO DIMINISHES GRADUALLY AS HIGH PRESSURE OVER THE ATLANTIC SHIFTS
SOUTHEAST AND THE LOW PRESSURE SYSTEM OVER IA SINKS SOUTHEASTWARD
OVERNIGHT. AN AXIS OF DEEPER MOISTURE PER PWATS OF 1.6-1.8 INCHES
AND 500-700MB RH COLLOCATED WITH BEST RADAR RETURNS THIS AFTERNOON
WILL SHIFT TOWARDS THE CENTRAL AND EASTERN PORTIONS OF THE CWA
TONIGHT. AS A RESULT...HAVE PRECIPITATION CHANCES SHIFTING EASTWARD
AND DIMINISHING THROUGH THE NIGHT AS BETTER FORCING/DEEPER MOISTURE
EXIT THE AREA. LOWS WILL BE IN THE 60S OVERNIGHT. WITH ABUNDANT
MOISTURE...RECENT/ONGOING RAINFALL...AND FAIRLY LIGHT WINDS EXPECTED
TONIGHT...ADDED IN PATCHY/AREAS OF FOG FOR LATE TONIGHT.

PRECIPITATION CHANCES CONTINUE FOR SUNDAY MORNING JUST PRIOR TO THE
DEPARTURE OF THE DIMINISHING 500MB TROUGH. EXPECT PATCHY/AREAS OF
FOG TO DIMINISH BY MID-LATE MORNING. A WEAK SHORTWAVE SLIDES THROUGH
TOWARDS THE AFTERNOON...BUT OTHERWISE THERE IS VERY LITTLE IN THE
WAY OF FORCING. DESPITE THIS...SOME MODELS SUGGEST SCATTERED
SHOWERS/STORMS DURING THE AFTERNOON...ESPECIALLY TO THE SOUTHEAST.
KEPT LOWER END-CHANCE/SLIGHT CHANCE POPS TO ACCOUNT FOR THIS...BUT
CONFIDENCE IS LOW. HIGHS SHOULD REACH INTO THE 70S AND LOW
80S...COOLEST NEAR LAKE MICHIGAN WHERE WINDS WILL GENERALLY BE OUT
OF THE NORTH-NORTHWEST.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 359 PM EDT SAT AUG 29 2015

AN UPPER LEVEL SHEAR AXIS SITUATED OVER THE LOWER/MID MS VALLEY
WEAKENS SUN NIGHT THROUGH MON AS UPPER RIDGING BUILDS OVER THE OH
VALLEY. BY TUE AN UPPER SHORT WAVE LIFTS NEWD INTO THE GTLKS REGION
CAUSING THE RIDGE TO FLATTEN SOMEWHAT. ADDITIONAL WEAK WAVES ARE
EXPECTED TO LIFT NEWD TOWARD THE GTLKS REGION BRINGING A CHANCE FOR
SCATTERED SHRA/TSRA TUE/WED WITH AFTERNOON HEATING BEING THE MORE
PRONOUNCED PERIODS FOR PRECIP CHANCES. THU THE RIDGE AXIS REDEVELOPS
WEST OF INDIANA ALLOWING FOR IMPULSES TO DROP SEWD TOWARD THE LOWER
GTLKS. THIS WILL CONT AFTN PRECIP CHANCES WITH WEAK ASCENT PRESENT
THROUGH FRI. STRONG INSTABILITY ISN`T EXPECTED SO GENERAL AFTN
SCATTERED TSTMS AGAIN. THE PRESENCE OF CLOUDS AND SCATTERED PRECIP
SHOULD PRECLUDE TEMPS BREAKING 90 SO CONT MID TO UPPER 80S THROUGH
SAT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 359 PM EDT SAT AUG 29 2015

RAIN SHOWERS OVER MUCH OF THE NORTHWESTERN PORTIONS OF THE FORECAST
AREA WILL GRADUALLY SHIFT EASTWARD OVERNIGHT AS SEVERAL UPPER LEVEL
DISTURBANCES MOVE THROUGH ALOFT. MOST OF THE CEILINGS WITHIN SHOWERS
TODAY AND UPSTREAM HAVE REMAINED VFR-MVFR AT VARIOUS SITES...SO HAVE
KEPT CEILINGS RANGING FROM 4000-7000FT THROUGH THE PERIOD. SHOWERS
ARE FAIRLY SCATTERED IN NATURE...MAKING IT DIFFICULT TO PINPOINT
EXACT TIMES OF PRECIPITATION FOR THE TAF SITES. KSBN MAY SEE A BRIEF
BREAK BEFORE SHOWER ACTIVITY RESTARTS LATER THIS AFTERNOON AS THE
NEXT UPPER LEVEL TROUGH MOVES IN. SHOWERS ARE MORE ISOLATED THIS
AFTERNOON NEAR KFWA BUT EXPECT ACTIVITY TO INCREASE TOWARDS THE LATE
AFTERNOON EARLY EVENING. WITH ABUNDANT MOISTURE THINKING THAT BOTH
SITES MAY HAVE A SHOT AT SEEING SOME LOWERED VISIBILITIES DUE TO FOG
LATE TONIGHT/EARLY SUNDAY...BUT CONFIDENCE WAS PRETTY LOW SO KEPT IT
MVFR AT WORST FOR NOW.


&&

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

$$

SYNOPSIS...MCD
SHORT TERM...MCD
LONG TERM...FRAZIER
AVIATION...MCD


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