Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 012351
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
751 PM EDT WED OCT 1 2014

.SYNOPSIS...
ISSUED AT 730 PM EDT WED OCT 1 2014

A LOW PRESSURE SYSTEM WILL MOVE TOWARD THE REGION TONIGHT AND
THURSDAY. SMALL CHANCES FOR PRECIPITATION WILL BEGIN ACROSS
WESTERN AREAS LATE TONIGHT AND INCREASE THROUGH THE DAY ON
THURSDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED
THURSDAY NIGHT ACROSS MOST OF THE REGION JUST AHEAD OF A STRONG
COLD FRONT THAT WILL USHER IN MUCH COOLER AIR.

LOW TEMPERATURES TONIGHT WILL FALL INTO THE LOWER AND MIDDLE 50S
AS SKIES BECOME MOSTLY CLOUDY. ABOVE NORMAL TEMPERATURES ARE
EXPECTED ON THURSDAY WITH HIGHS RANGING FROM THE MIDDLE 70S NORTH
TO LOWER 80S SOUTH.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 334 PM EDT WED OCT 1 2014

DEEP TROUGH TO THE WEST THAT HAS BROUGHT LOTS OF RAINFALL ACROSS THE
PLAINS AND MIDWEST WILL BEGIN TO GAIN SOME MOMENTUM BUT ALSO
STRENGTHEN SIGNIFICANTLY (MAINLY IN THE LONG TERM PERIOD) AS A
SERIES OF STRONGER PIECES OF ENERGY EJECT FROM CLOSED LOW PRESSURE
OVER NORTHERN CANADA. FOR THE SHORT TERM PERIOD THE MAIN IMPACTS OF
THE PROCESS WILL BE A FURTHER CARVING OF THE TROUGH AND SUBSEQUENT
HEIGHT RISES TO USHER IN A QUICK SHOT OF MUCH WARMER AIR BUT ALSO
SET THE STAGE FOR INCREASING MOISTURE. CONVECTION OVER FAR WESTERN
ILLINOIS WILL WORK EAST TONIGHT. MODELS VARY ON TIMING AND EXTENT OF
THIS AREA LATER TONIGHT INTO EARLY THURSDAY BEFORE MAIN LOW LEVEL
JET SETS UP TO THE WEST AGAIN. WHILE SOME SIGNALS SUGGEST A DRAMATIC
INCREASE IN POPS IS WARRANTED IN THIS TIME FRAME ENOUGH UNCERTAINTY
EXISTS TO HOLD OFF ON EXTREME INCREASES AND SIMPLY INTRODUCE SLGT
CHC/CHC POPS OVERNIGHT IN WESTERN AREAS AND WILL DEFER TO EVE SHIFT
TO MONITOR TRENDS. BETTER CHANCES DEFINITELY BEGIN TO ARRIVE
THURSDAY AFTERNOON AS MAIN WAVE DRAWS CLOSER WITH LIKELY POPS
WARRANTED BY MID AFTERNOON IN WEST AREAS. HIGHS SHOULD REACH THE MID
70S TO AROUND 80 WITH LOCATIONS IN THE WEST AND NORTH COOLEST DUE TO
INCREASING CLOUD COVER. IF RAINFALL DOES OCCUR/LINGER IN THE WEST
HIGHS COULD BE IN JEOPARDY OF BEING REACHED.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 334 PM EDT WED OCT 1 2014

POTENT SRN STREAM WAVE ACRS THE CNTRL ROCKIES WILL DRIVE EWD SHRT
TERM AND THEN PHASE W/RAPIDLY SEWD DIGGING NRN STREAM SW OUT OF WRN
AB FRI. RESULTING SIGLY DEEP TROUGH DVLPMNT ACRS THE WRN GREAT
LAKES SUBSEQUENTLY HIGHLITES THE PD EARLY ON.

AS WAS THE CASE YDA AND IN CONJUNCTION W/PRIOR SHIFT WILL AGAIN BUMP
POPS HIGHER LT THU NIGHT THROUGH SAT AM IN REFLECTION OF GREATER
TROUGH DIG/AMPLIFICATION SEEN THROUGHOUT THE 12Z GUIDANCE SPECTRUM.
IN FACT YDA/S OUTLIER ECMWF H7-5 EVOLUTION ALOFT NOW SEEN IN BOTH
THE GFS AND GEM...TAKING H5 HFC IN EXCESS OF 22 DM THROUGH SRN IN
FRI NIGHT. THUS WILL BREAK EVEN HIGHER LT FRI NIGHT W/LIKELY
MENTION ACRS THE NORTH IN LIGHT OF BOTH STGR LL THERMAL TROUGH
WRAPPING SEWD THROUGH CWA UNDERNEATH WHAT SHLD BE A ROBUST COMMAHEAD INVOF
OF BOTTOMING NRN STREAM SW. THAT SAID...ENOUGH DETAIL/TIMING
UNCERTAINTY EXISTS TO HOLD W/HIGH CHC MENTION FOR THE MOMENT SAT AM.
HWVR REGARDLESS OF SOLUTION YDA/S 40 DEGREE HOLD HUNCH HOLDS PER
LWR TRENDING GUIDANCE TEMPS AND WILL HEDGE LWR FURTHER THIS CYCLE.

SLW MODERATION FOLLOWS THEN INTO EARLY NXT WEEK ALTHOUGH PUNCTUATED
BY A PAIR OF WAVES EMBEDDED WITHIN STEEP NW FLW ALOFT.
TIMING/DETAILS VARY CONSIDERABLY YET WILL FOLLOW SUPER BLEND
APPROXIMATION IN SPITE OF ANYTHING ELSE MAKING A MORE COMPELLING
CASE TO STRAY AT THIS POINT.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 728 PM EDT WED OCT 1 2014

VFR TO START THE PERIOD BUT CONDITIONS WILL BEGIN TO DETERIORATE
LATE IN THIS VALID PERIOD. EXPECT A DECAYING AREA OF SHOWERS IN
VICINITY OF TAF SITES LATE TONIGHT INTO THURSDAY MORNING. NOT
CURRENTLY EXPECTING RESTRICTIONS WITH DRY LOWER LEVELS INITIALLY.
MORE SUBSTANTIAL RAIN AND RESTRICTIONS EXPECTED LATER THU AND
ESPECIALLY THU NIGHT AHEAD OF STRONG COLD FRONT. FOR NOW KEPT TAFS
IN THE VFR CATEGORY BUT THIS COULD CHANGE THU AFTERNOON DEPENDING
ON HOW CONVECTION DEVELOPS.


&&

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

$$

SYNOPSIS...LASHLEY
SHORT TERM...FISHER
LONG TERM...T
AVIATION...LASHLEY


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