Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 010041
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
841 PM EDT FRI JUL 31 2015

.SYNOPSIS...
ISSUED AT 400 PM EDT FRI JUL 31 2015

SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN PORTIONS OF
THE FORECAST AREA WILL DIMINISH THIS EVENING. OTHERWISE...
EXPECT DRY CONDITIONS TO PREVAIL OVERNIGHT. LOWS WILL BE
IN THE UPPER 50S AND 60S. ON SATURDAY EXPECT MOSTLY SUNNY
SKIES THROUGH EARLY AFTERNOON...THEN INCREASING CLOUDS AND A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS. HIGHS WILL RANGE
FROM THE UPPER 70S NEAR LAKE MICHIGAN TO THE MID 80S INLAND.

&&

.UPDATE...
ISSUED AT 801 PM EDT FRI JUL 31 2015

UPDATED FORECAST THIS EVENING TO REMOVE AFTERNOON WORDING AND
REMOVE POPS...OTHERWISE NO CHANGES MADE TO PREVIOUS FORECAST.
NORTHWEST GUSTS SHOULD CONTINUE TO RAPIDLY DIMINISH OVER THE NEXT
HOUR WITH BOUNDARY DECOUPLING...ALLOWING FOR GOOD RADIATIONAL
COOLING CONDITIONS TONIGHT WHICH SHOULD SUPPORT PREVIOUS MINS FROM
UPPER 50S TO LOWER 60S.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 400 PM EDT FRI JUL 31 2015

QUIET FORECAST IN STORE FOR THE IMMEDIATE SHORT TERM WITH DRY
WEATHER EXPECTED TONIGHT AND SATURDAY MORNING IN THE WAKE OF THE
FRONTAL PASSAGE THIS AFTERNOON. HIGH PRESSURE CENTERED OVER MISSOURI
WILL SHIFT EASTWARD INTO WESTERN TENNESSEE BY 21Z SATURDAY...WHICH
KEEPS OUR CWA ON THE PERIPHERY UNDER CONTINUED WESTERLY WINDS. FLOW
ALOFT REMAINS FAIRLY ZONAL OUT OF THE WEST-NORTHWEST AS FAIRLY
STATIONARY 500MB LOW SPINS OVER HUDSON BAY. MODELS ONCE AGAIN
CONFLICTING ON POPS SATURDAY AFTERNOON. A WEAK SHORTWAVE ROTATING
AROUND THE LOW WILL APPROACH THE AREA...PROVIDING SOME SUPPORT FOR
PRECIPITATION. MOISTURE WILL ONCE AGAIN BE ADVECTED INTO THE
REGION...WITH PWATS EXPECTED TO BE SIMILAR TO TODAY/AROUND 1.3
INCHES. INSTABILITY IS FORECAST TO RISE INTO THE 1500 J/KG ML CAPE
RANGE...SO THINKING ISOLATED SHOWERS/T-STORMS ARE NOT OUT OF THE
QUESTION. HOWEVER...FORCING IS NOT AS STRONG AS IT WAS TODAY...SO
KEPT LOW CHANCE POPS FOR NOW.

OTHERWISE...GUSTY ONSHORE WINDS SATURDAY WILL LEAD TO WAVE HEIGHTS
OF 2 TO 3 FEET AND STRONG CURRENTS ALONG THE BERRIEN COUNTY SHORELINE.
KEPT A MODERATE SWIM RISK FOR THIS TIME PERIOD.

&&

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 400 PM EDT FRI JUL 31 2015

PESKY UPPER LOW WILL CONTINUE TO MEANDER OVER THE HUDSON BAY
REGION THROUGH MIDDLE OF NEXT WEEK. CENTRAL CONUS RIDGE TO ALSO
BUILD WEST AND NORTH KEEPING NORTHWEST FLOW OVER THE GREAT LAKES.
THIS WILL RESULT IN NORMAL TO BELOW NORMAL TEMPERATURES FOR MUCH
OF THE PERIOD ALONG WITH PERIODIC CHANCES FOR SHOWERS AND
THUNDERSTORMS WITH WEAK EMBEDDED SHORT WAVES AND ATTENDANT SURFACE
FRONTS.

BEST CHANCES FOR SHOWERS AND STORMS STILL LOOKS TO BE SUNDAY AND
SUNDAY NIGHT. SHARP SHORT WAVE TROUGH WILL ROTATE THROUGH THE LAKES
REGION ALONG WITH ASSOCIATED SURFACE COLD FRONT. MOISTURE ADVECTION
AHEAD OF THIS WAVE AND DECENT MID LEVEL FORCING SHOULD ALLOW AREA OF
PRECIPITATION TO MOVE THROUGH THE REGION. RAISED POPS FURTHER TO
HIGH CHANCE CATEGORY BUT STOPPED SHORT OF LIKELY GIVEN CONVECTIVE
NATURE AND MODEL ISSUES. FRONT NOW LOOKS TO BE EXITING THE AREA ON
MONDAY BUT SECONDARY SHORT WAVE COULD PRODUCE SOME AFTERNOON
CONVECTION SO ALLOWED LOW CHANCE POPS TO CONTINUE FOR NOW MONDAY
AFTERNOON. REMAINDER OF FORECAST REMAINS UNCERTAIN WITH MODELS FLIP
FLOPPING ON A STRONGER WAVE MID WEEK MOVING THROUGH THE OHIO VALLEY.
STAYED WITH SOME LOW CHANCE POPS WITH HIGHEST IN THE SOUTH NEAR SFC
BOUNDARY. EXPECT ADDITIONAL CHANGES IN GUIDANCE AS THEY TRY TO
RESOLVE THE WEAK WAVES WITHIN LONG WAVE TROUGH AND ANY CONVECTIVELY
INDUCED SHORT WAVES UPSTREAM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 801 PM EDT FRI JUL 31 2015

THE THREAT OF SHOWERS HAS ENDED AT TERMINALS AS SFC FRONT HAS
CLEARED TO THE SOUTH. DRIER LOW LEVEL AIR WILL CONTINUE TO FILTER
SOUTHWARD THIS EVENING WITH MAINLY CLEAR SKIES EXPECTED THROUGH
THE NIGHT. NORTHWEST WINDS AROUND 10 KNOTS EARLY THIS EVENING
SHOULD BECOME WEST AROUND 5 KNOTS AFTER 02Z WITH CENTER OF SFC
ANTICYCLONE DRIFTING ACROSS SOUTHERN ILLINOIS TONIGHT. LOW LEVEL
WINDS TO BACK ON SATURDAY AS SFC HIGH DRIFTS SOUTH OF THE
AREA...ALLOWING FOR SOME RETURN LOW LEVEL WARM/MOISTURE ADVECTION.
HOWEVER WILL KEEP TAFS DRY AS ANY SHOWER/THUNDERSTORM ACTIVITY IS
EXPECTED TO REMAIN VERY ISOLATED WITH WEAK FORCING. MODEST
GRADIENT SHOULD SUPPORT SOME WESTERLY GUSTS INTO THE 15 TO 18 KNOT
RANGE ONCE AGAIN ON SATURDAY AFTERNOON.

&&

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

$$

UPDATE...MARSILI
SYNOPSIS...MCD
SHORT TERM...MCD
LONG TERM...SLASH
AVIATION...MARSILI


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