Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 301030
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
630 AM EDT TUE SEP 30 2014

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

&&

.SYNOPSIS...
ISSUED AT 237 AM EDT TUE SEP 30 2014

A WEAK LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL PUSH A COOL
FRONT ACROSS CENTRAL INDIANA TODAY. NO PRECIPITATION IS
EXPECTED...HOWEVER A FEW PASSING CLOUDS ALONG WITH NORTHERLY FLOW
IS EXPECTED TODAY.

MORE DRY WEATHER IS EXPECTED TONIGHT AND WEDNESDAY AS WEAK HIGH
PRESSURE LINGERS IN THE AREA IN THE WAKE OF THE FRONT.

A MUCH STRONGER COLD FRONT WILL PUSH INTO THE REGION ON THURSDAY
AND PASS ACROSS CENTRAL INDIANA ON THURSDAY NIGHT. THE FIRST RAIN
SHOWERS IN IN OVER A WEEK ARE EXPECTED ON THURSDAY NIGHT WITH THE
PASSAGE OF THE COLD FRONT. MUCH COOLER AIR WILL ARRIVE FOR FRIDAY
AND THE WEEKEND IN THE WAKE OF THE FRONT ON FRIDAY.

THE COOLER THAN NORMAL TEMPERATURES ARE EXPECTED TO LINGER INTO
NEXT WEEK.

&&

.NEAR TERM /TODAY/...

ISSUED AT 237 AM EDT TUE SEP 30 2014

SURFACE ANALYSIS EARLY THIS MORNING SHOWS A WEAK AREA OF LOW
PRESSURE OVER THE EASTERN GREAT LAKES ALONG WITH A TRAILING COLD
FRONT TO THE SOUTHWEST ACROSS NORTHERN INDIANA AND CENTRAL
ILLINOIS. COOLER NORTH TO NORTHEASTERLY SURFACE FLOW WAS FOUND IN
THE WAKE OF THE FRONT. NO PRECIP WAS FOUND WITH THE FRONT AMID THE
BONE DRY COLUMN...HOWEVER IR IMAGES DID SHOW A FEW CLOUDS
ASSOCIATED WITH THIS FEATURE. SURFACE DEW POINTS REMAINED IN THE 50S.

MAIN CHALLENGE WITH TODAY/S FORECAST WILL BE TEMPS. BOTH THE GFS
AND NAM SUGGEST THE FRONTAL BOUNDARY WILL SWEEP ACROSS THE FORECAST
AREA THIS MORNING...HOWEVER DUE TO A LACK OF MOISTURE NO PRECIP
WILL BE EXPECTED. THE MAIN DIFFERENCE WILL BE A CHANGE IN THE
SURFACE FLOW AS IT BECOMES MORE NORTHERLY. 850MB SURFACE SHOWS
SOME WEAK COLD AIR ADVECTION TODAY AS 850MB TEMPS FALL TO LESS
THAN 12C. FORECAST SOUNDINGS REMAIN DRY...HOWEVER TIME HEIGHTS
SHOW SOME LOWER LEVEL MOISTURE DUE TO THE CLOUDS ASSOCIATED WITH
THE FRONTAL PASSAGE. CONVECTIVE TEMPERATURES WILL BE UNATTAINABLE
TODAY AS THE WEAK COLD AIR ADVECTION WILL ONGOING. THUS WILL TREND
TOWARD PARTLY CLOUDY SKIES TODAY...WITH MORE SUNSHINE LATER THIS
AFTERNOON AS THE LIMITED CLOUD COVER WITH THE FRONT PASSES. AS
FOR TEMPS WILL WORK A BLEND OF THE MAV AND MET.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...

ISSUED AT 237 AM EDT TUE SEP 30 2014

AFTER A WEEK PLUS OF FALL WARMTH AND SUPERB FALL WEATHER...CHANGES
ARE HEADED TO THE FORECAST BY THE END OF THIS PERIOD.

GFS AND NAM SUGGEST UPPER RIDGING WILL BEGIN TO MOVE THROUGH THE
WESTERN GREAT LAKES TONIGHT AND THEN THROUGH THE OHIO VALLEY AND
MICHIGAN ON WEDNESDAY BEFORE DEPARTING ION WEDNESDAY NIGHT TO THE
EAST. THE UPPER RIDGE WILL PROVIDE A FEW MORE DAYS OF DRY AND
PLEASANT WEATHER THROUGH THURSDAY MORNING. FORECAST SOUNDINGS
REMAIN DRY THROUGH THURSDAY MORNING AND TIME HEIGHT SECTIONS
CONTINUE TO SHOW MORE OF THE SAME...JUST A DRY COLUMN. THUS WILL
CONTINUE THE ONGOING TREND OF MOSTLY CLEAR NIGHTS AND MOSTLY SUNNY
DAYS THROUGH THURSDAY MORNING. AS FOR TEMPS THROUGH WEDNESDAY
NIGHT...COOL LIGHT TO CALM NORTHERLY FLOW LOOKS TO REMAIN IN PLACE
TONIGHT AMID CLEAR SKIES. THUS WITH GOOD RADIATIONAL COOLING
CONDITIONS IN PLACE WILL TREND LOWS AT OR BELOW MAVMOS. SURFACE
FLOW TURNS SOUTHEASTERLY ON WEDNESDAY AS WARMER AIR BEGINS TO
ARRIVE FROM THE SOUTHWEST. WILL TREND HIGHS HERE CLOSER TO THE
WARMER MAV. GIVEN THE WEAK WARM AIR ADVECTION IN PLACE AHEAD OF THE
APPROACHING COLD FRONT ON WEDNESDAY NIGHT WILL TREND LOWS THEN WARMER.

ON THURSDAY THINGS FINALLY START GETTING INTERESTING AS A STRONG
TROUGH PUSHES THROUGH THE CENTRAL PLAINS AND ALONG WITH A COLD
FRONT. THE FRONT DOES NOT LOOK TO ARRIVE UNTIL THURSDAY
NIGHT...HOWEVER FORECAST SOUNDINGS ON THURSDAY AFTERNOON SHOW
REACHABLE CONVECTIVE TEMPERATURES AND CENTRAL INDIANA WILL BY THEN
BE IN THE WARM SECTOR. THUS WILL TREND HIGHS ON THURSDAY WARMER
THAN MAVMOS GIVE THE STRONG SOUTHERLY FLOW AHEAD OF THIS
APPROACHING SYSTEM...BUT WILL ALSO INCLUDE A LOW CHANCE POPS FOR
THE LATE AFTERNOON HOURS AS CONVECTIVE TEMPERATURES MAY BE REACHED.

BEST CHANCES FOR SHOWERS AND STORMS REMAIN ON THURSDAY NIGHT AS
THE COLD FRONT PASSES. FORECAST SOUNDINGS SHOW DEEP SATURATION
WITH PWATS OVER 1.50 INCHES. 310K GFS ISENTROPIC SURFACE SHOWS
GOOD UPGLIDE ALONG WITH SPECIFIC HUMIDITIES OVER 5 G/KG. LOWER
LEVEL Q VECTORS ALSO SHOW EXCELLENT CONVERGENCE ALONG THE FRONT.
THUS WILL TREND POPS HIGHER ON THURSDAY NIGHT AND TREND LOWS AT OR
ABOVE MEXMOS AS COLD AIR ADVECTION REALLY DOESN/T LOOK TO TAKE
SHAPE UNTIL AFTER 12Z FRIDAY.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...

ISSUED AT 237 AM EDT TUE SEP 30 2014

ENSEMBLES INDICATE THAT UPPER TROUGH AND SURFACE FRONTAL SYSTEM
THAT IS EXPECTED TO BEGIN AFFECTING THE AREA AT THE TAIL END OF
THE SHORT TERM...WILL BE IN THE PROCESS OF PASSING THROUGH ON
FRIDAY. WILL CONTINUE WITH RATHER HIGH POPS ON FRIDAY.

INITIAL UPPER TROUGH LOOKS PROGRESSIVE...WITH THE ENSEMBLES
INDICATING SYSTEM WILL MOVE OFF TO THE EAST BY SATURDAY. WILL KEEP
SATURDAY DRY. ANOTHER POTENTIAL UPPER DISTURBANCE MAY DROP SOUTHEAST
INTO THE AREA BY NEXT SUNDAY OR MONDAY AS LONG WAVE TROUGHING
DEVELOPS OVER THE EASTERN PARTS OF THE COUNTRY. WILL CONTINUE WITH
CHANCE POPS ON SUNDAY TO COVER THIS POTENTIAL DISTURBANCE.

SEVERAL ENSEMBLES LINGER THE PRECIPITATION THREAT INTO NEXT MONDAY
AS WELL. FOR NOW...WILL KEEP NEXT MONDAY DRY AND WATCH THE TRENDS.

&&

.AVIATION /DISCUSSION FOR THE 301200Z TAFS/...
ISSUED AT 630 AM EDT TUE SEP 30 2014

AREA OF IFR CEILINGS...004-008 AGL...WITH PATCHY LIFR CEILINGS AND
VISIBILITIES NEAR THE LEADING EDGE OF THE LOW CLOUD DECK...
CONTINUES TO DROP SOUTHEAST IN THE WAKE OF A WEAK COLD FRONT. THE
MORE SOUTHERN TAF SITES...KIND/KHUF/KBMG...WILL BE IMPACTED BY THESE
CONDITIONS FOR SEVERAL HOURS THIS MORNING. SHORT TERM MODEL DATA
SUGGEST THESE LOW CEILINGS WILL EVENTUALLY LIFT AND SCATTER OUT BY
EARLY AFTERNOON. APPEARS THE CEILINGS AT KLAF HAVE ALREADY LIFTED TO
ABOVE IFR BASED ON UPSTREAM OBSERVATIONS.

SURFACE WINDS SHOULD BECOME 340-010 AT 7-10 KTS OVER THE NEXT COUPLE
OF HOURS AS FRONT PASSES BY.

&&

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

$$

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

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