Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 021453
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1053 AM EDT THU OCT 2 2014

.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.

&&

.SYNOPSIS...
ISSUED AT 213 AM EDT THU OCT 2 2014

AN ACTIVE WEATHER DAY IS STORE TODAY. SHOWERS AND THUNDERSTORMS
ARE POSSIBLE FOR THE REMAINDER OF THE MORNING AS A WARM FRONT
,LIFTS ACROSS THE REGION. AS MORNING RAINS EXIT AND DIMINISH IN
COVERAGE... ARM AND MORE HUMID SOUTHERLY FLOW WILL RETURN THIS
AFTERNOON. THIS WILL RESULT IN MORE ABOVE NORMAL TEMPERATURES
TODAY.

A STRONG COLD FRONT WILL PUSH TOWARD CENTRAL INDIANA TONIGHT AND
PASS ACROSS THE STATE EARLY ON FRIDAY. SHOWERS AND THUNDERSTORMS WILL
ACCOMPANY THE FRONT...RESULTING IN STORMY WEATHER TONIGHT AND
FRIDAY. GUSTY WEST WINDS ARE EXPECTED ON FRIDAY IN THE WAKE OF THE
FRONT.

MUCH COLDER AIR WILL ARRIVE IN THE AREA BY SATURDAY AS A COLD
CANADIAN AIR MASS SETTLES OVER THE OHIO VALLEY FOR THE WEEKEND.

&&

.NEAR TERM /REST OF TODAY/...
ISSUED AT 1009 AM EDT THU OCT 2 2014

REMNANT OVERNIGHT CONVECTION HAS MOVED INTO THE REGION THIS
MORNING...MAINLY IMPACTING AREAS ALONG AND NORTH OF I-70. PRECIP
BEING AIDED BY A WARM FRONT LIFTING THROUGH THE FORECAST AREA AT
THIS TIME. CLOUDS AND RAIN HOLDING MOST TEMPS DOWN...WITH 13Z
TEMPS IN THE 60S.

ONGOING ACTIVITY THIS MORNING ALONG WITH NEWER SHORT RANGE
GUIDANCE WILL FACILITATE CHANGES TO THE FORECAST FOR THE MORNING
UPDATE. LOW LEVEL JET NOTED IN THE FLOW APPEARS TO BE ASSISTING
CONVECTION FROM THE WABASH VALLEY WEST INTO CENTRAL ILLINOIS. THIS
FEATURE WILL SHIFT NORTHEAST WITH THE WARM FRONT INTO EARLY
AFTERNOON...AND SHOULD SEE PRECIP LIKEWISE SHIFT NORTHEAST AND
DECREASE IN COVERAGE. WILL FOCUS HIGHEST POPS TO THE NORTHWEST OF
THE INDY METRO THROUGH 18Z. STILL LIKELY TO BE A RELATIVE LULL IN
CONVECTIVE COVERAGE UNTIL LATE AFTERNOON AS STORM COMPLEX OVER
MISSOURI APPROACHES FROM THE WEST. WILL BRING POPS BACK UP LATE...
WITH BULK OF THE MORE WIDESPREAD RAINFALL STILL SLATED TO ARRIVE
TONIGHT WITH THE COLD FRONT.

OTHER BIG CHANGE THIS MORNING IS TO FORECAST HIGHS AS ABUNDANCE OF
CLOUD COVER WILL LIMIT TEMP RISES MUCH MORE THAN PREVIOUSLY
THOUGHT. WHILE STILL LIKELY TO SEE SOME SUN INTO THE AFTERNOON
SOUTH OF I-70...EXPECT A LOT OF CLOUDS FURTHER NORTH. DROPPED
HIGHS 5-7 DEGREES OVER THE NORTHERN HALF OF THE FORECAST AREA WHERE
TEMPS WILL REMAIN UNDER 80. WILL WATCH TRENDS AS MAY NEED TO LOWER
THESE TEMPS EVEN FURTHER. FURTHER SOUTH...PRESENCE OF SUN AND WARM
ADVECTION SOUTH OF THE BOUNDARY SHOULD STILL ENABLE LOCATIONS TO
CLIMB INTO THE LOWER 80S WITH PERHAPS A FEW LOCATIONS APPROACHING 85
DEGREES ALONG OUR SOUTHERN BORDER.

ZONE AND GRID UPDATES OUT.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...

ISSUED AT 213 AM EDT THU OCT 2 2014

GFS AND NAM ARE IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN
AND WILL USE A BLEND. THE MAIN FOCUS OF THIS PERIOD WILL BE THE
FRONTAL PASSAGE TONIGHT.

NUMEROUS INGREDIENTS COMING TOGETHER FOR RAIN TONIGHT. BY 00Z
FRIDAY THE GFS 305K ISENTROPIC SURFACE SHOWS BROAD LIFT ACROSS
THE AREA WITH SPECIFIC HUMIDITIES OVER 9 G/KG. UPPER SUPPORT IS
PLENTIFUL AS THE DEEP TROUGH OVER THE CENTRAL PLAINS IS POISED TO
PUSH TOWARD INDIANA OVERNIGHT PROVIDING PLENTY OF UPPER SUPPORT.
FORECAST SOUNDINGS SHOW PLENTY OF DEEP MOISTURE AVAILABLE. LOWER
LEVEL Q VECTOR CONVERGENCE IS ALSO FAVORABLE. THUS WILL TREND
TOWARD 100 POPS TONIGHT. AS FOR TEMPS WILL TREND AT OR ABOVE
MAVMOS AS THE COLD FRONTAL PASSAGE DOES NOT APPEAR TO OCCUR UNTIL
AFTER 12Z FRIDAY.

THE STRONG COLD FRONT IS EXPECTED TO PASS ON FRIDAY MORNING. MUCH
DRYER AIR ARRIVES AS ISENTROPIC LIFT IS LOST BY 18Z ALONG WITH THE
ACCESS TO MOIST AIR LONG THE ISENTROPIC SURFACE. FORECAST
SOUNDINGS BEGIN TO DRY OUT AS STRONG COLD AIR ADVECTION BEGINS.
WILL AIM FOR STEADY OR SLOWLY FALLING TEMPERATURES THROUGH THE DAY
WITH DAYTIME HIGHS AT OR SHORTLY AFTER 12Z. WILL CONTINUE WITH
HIGH POPS AS ONGOING RAIN AHEAD OF THE FRONT IS EXPECTED DURING
THE FIRST FEW HOURS AFTER 12Z. WILL TREND POPS LOWER AS THE DAY
PROGRESSES.

ALSO NOTABLE ON FRIDAY IS THE STRONG LOWER LEVEL PRESSURE
GRADIENT THAT WILL BE IN PLACE ACROSS THE AREA. THIS SHOULD RESULT
IN GUSTY WINDS ON FRIDAY AND FRIDAY NIGHT.

FOR FRIDAY NIGHT THROUGH SATURDAY NIGHT THE GFS AND NAM SUGGEST
STRONG TROUGH WILL BE IN PLACE ALOFT OVER THE GREAT LAKES AND OHIO
VALLEY. STRONG COLD AIR ADVECTION WILL CONTINUE ON FRIDAY NIGHT
AND INTO SATURDAY AS 850MB TEMPERATURES FALL TO BELOW -4C AND
THICKNESSES FALL TO BELOW 535. FORECAST SOUNDINGS THROUGH THE
PERIOD SHOW ATTAINABLE CONVECTIVE TEMPS AMID A BROAD CYCLONIC
FLOW. THUS CANNOT RULE OUT A STRAY SHOWER DURING THE DAY ON
SATURDAY. WITH ALL THE COLD AIR ADVECTION...FORECAST SOUNDINGS
ALSO SHOWING SIGNS OF WINTER LIKE TRAPPED STRATOCU BENEATH A MID
LEVEL INVERSION. THUS WILL TRY TO KEEP A MENTION OF A SPRINKLE OR
LOW CHC POP ON SATURDAY. AS FOR TEMPS...GIVEN THE STRONG COLD AIR
ADVECTION...WILL BE TRENDING COLDER AT MOST TIMES DURING THE
PERIOD.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...

ISSUED AT 213 AM EDT THU OCT 2 2014

ENSEMBLES INDICATE A DEEP UPPER TROUGH OVER THE EASTERN PARTS OF THE
COUNTRY AT THE BEGINNING OF THE EXTENDED WILL GRADUALLY LIFT OFF TO
THE NORTHEAST...LEAVING RELATIVELY ZONAL FLOW OVER THE LOCAL AREA BY
THE MIDDLE OF NEXT WEEK.

ENSEMBLES CONTINUE TO KEY IN A POTENTIAL UPPER DISTURBANCE THAT WILL
DROP SOUTHEAST INTO THE AREA IN THE SUNDAY OR MONDAY TIME FRAME.
WILL GO WITH CHANCE POPS DURING THOSE PERIODS TO COVER THIS
POTENTIAL DISTURBANCE.

PRECIPITATION THREAT SHOULD DIMINISH TOWARDS THE MIDDLE OF NEXT WEEK
AS UPPER FLOW FLATTENS OUT AND HEIGHTS RISE. WILL GO DRY FOR NEXT
TUESDAY AND WEDNESDAY.

&&

.AVIATION /DISCUSSION FOR THE 021500Z TAFS/...
ISSUED AT 1053 AM EDT THU OCT 2 2014

RAIN HAS MOVED OUT OF KLAF AND ALSO KBMG FOR THE MOST PART BUT IS
STILL HANGING AROUND KIND AND KHUF. THIS SHOULD MOVE OFF OVER THE
NEXT COUPLE OF HOURS AND UPDATED TAFS TO INDICATE THIS. ADDED SOME
VCSH LATER THIS AFTERNOON AT KLAF AS THIS IS LOOKING MORE LIKELY BUT
STILL NOT CONFIDENT ENOUGH TO INCLUDE THUNDER OR EXPLICIT RAIN
MENTION. STILL LOOKS LIKE BEST CHANCES FOR WIDESPREAD THUNDERSTORMS
IS COMING IN AFTER 0-6Z AND LEFT THIS PORTION OF THE TAFS ALONE.
PREVIOUS DISCUSSION FOLLOWS...

OVERALL...EXPECTING SHOWER ACTIVITY AT THE TAF SITES THROUGH ABOUT
MIDDAY...WITH THE MOST WIDESPREAD ACTIVITY AT KHUF/KLAF. DUE TO THE
ELEVATED NATURE OF THE CONVECTION...CEILINGS AND VISIBILITIES SHOULD
REMAIN ABOVE IFR...EXCEPT BRIEF IFR VISIBILITY RESTRICTIONS POSSIBLE
IN THE HEAVIER PRECIPITATION AREAS. PRECIPITATION SHOULD DIMINISH
DURING THE MIDDAY HOURS AS VORT CENTER MOVES OFF TO THE NORTHEAST.

MAY SEE MORE CONVECTIVE DEVELOPMENT IN THE KHUF/KLAF AREAS TOWARDS
THE MID TO LATE AFTERNOON HOURS AS THE TAIL END OF ILLINOIS VORT
CENTER GETS STRUNG OUT OVER THE NORTHWEST ZONES...BUT CONFIDENCE IS
LOW HERE AS MODELS DISAGREE AS TO WHETHER CONVECTION WILL DEVELOP
ALONG THIS FEATURE OR NOT.

OUTSIDE OF ANY PRECIPITATION AREAS...CEILINGS GENERALLY AT OR ABOVE
050 WITH SURFACE WINDS 150-180 AT 7-11 KTS.

&&

.IND WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SYNOPSIS...PUMA/RYAN
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....JAS
AVIATION...JAS

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