FXUS63 KIND 150447
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1145 PM EST MON DEC 14 2009

.AVIATION...DISCUSSION FOR 150600Z TAF ISSUANCE. WIDESPREAD CEILINGS 
AROUND 015 CURRENTLY ACROSS THE FORECAST AREA IN THE WAKE OF COLD 
FRONT. STILL SOME AREAS OF IFR CEILINGS AROUND...007-009 ABOVE 
GROUND LEVEL...BUT AREAL EXTENT HAS BEEN DIMINISHING OVER THE PAST 
COUPLE OF HOURS AS LOW LEVEL DRY ADVECTION HAS BEEN WORKING ON THE 
CLOUD BASES FROM BELOW. DON/T THINK IFR CEILINGS WILL BE 
SUFFICIENTLY WIDESPREAD BY ISSUANCE TIME TO INCLUDE IN THE FORECAST. 
BACK EDGE OF CLOUD DECK APPROACHING THE MISSISSIPPI RIVER...SO 
SHOULD SEE CEILINGS BEGINNING TO DISSIPATE TOWARDS 151500Z. 

SURFACE WINDS HAVE NOT BEEN AS STRONG AS PREVIOUSLY EXPECTED...BUT 
THIS EVENING/S SOUNDING AND MODEL DATA SUGGEST POTENTIAL FOR SOME 
WIND GUSTS TO AROUND 20KTS FROM 290-310 HEADINGS FOR THE REST OF THE 
NIGHT.

&&

.DISCUSSION...ACROSS THE FORECAST AREA THIS AFTERNOON...TEMPERATURES 
REBOUNDED NICELY INTO THE 50S AS THE INVERSION SHALLOWED OUT 
SUBSTANTIALLY AND ALLOWED SOME CLEARING TO OCCUR AHEAD OF THE 
FRONTAL BOUNDARY CURRENTLY STRETCHING FROM NEAR GARY TO DECATUR IL 
AND ST LOUIS. DEWPOINTS WERE IN THE LOW TO MID 40S...WITH BREEZY 
CONDITIONS OUT OF THE SOUTHWEST. AN ABRUPT CHANGE BACK TO COLD 
CONDITIONS IS IN THE OFFING AS THE AFOREMENTIONED COLD FRONT PUSHES 
QUICKLY THROUGH THE AREA THIS EVENING.

FORECAST FOCUS OF THE DAY WILL GENERALLY BE TEMPERATURES...AS 
PRECIPITATION APPEARS UNLIKELY.

MODELS WERE IN A DECENT STATE OF AGREEMENT AND A BLEND WAS USED 
TODAY. THE FRONT WILL BLAST THROUGH THE AREA THIS EVENING...REACHING 
OUR NORTHWEST CORNER IN THE NEXT COUPLE OF HOURS...THROUGH IND 
AROUND 01Z...AND EXITING OUR SOUTHEAST BEFORE MIDNIGHT. LOW LEVEL 
MOISTURE HAS FAILED TO PRODUCE ANY DRIZZLE TODAY...AND UPSTREAM OBS 
INDICATE LITTLE TO NO PRECIPITATION OCCURRING. ISENTROPIC SURFACES 
SHOW STRONG DOWNGLIDE AFTER FRONTAL PASSAGE TONIGHT AND COLUMN GETS 
DRIER AND DRIER...SO HAVE REMOVED ALL WEATHER FROM GRIDS. MAIN 
IMPACT OF THE BOUNDARY WILL BE RETURN TO LOW OVERCAST SKIES AND 
QUICK COOLING.

REMAINDER OF THE SHORT TERM...AND INDEED MOST OF THE FORECAST 
PERIOD...IS DRY AS THE ARCTIC HIGH SETTLES INTO THE CENTRAL PART OF 
THE NATION AND SLOWLY PUSHES EASTWARD BEFORE RETREATING NORTHWARD 
LATE IN THE WEEK.

ON TEMPERATURES...MAV LOOKS GOOD THROUGHOUT THE SHORT TERM...AS IT 
DEPICTS GOOD LOW LEVEL COOLING OCCURRING...BUT BULK OF COLDEST AIR 
IS NOT LIKELY TO ARRIVE BY END OF THE OVERNIGHT PERIOD...AND DEPICTS 
WARMING TOMORROW AS CLEARING IS LIKELY TO BEGIN IN THE DAY...AND 
THAT SHOULD ALLOW US TO RECOVER TO LEVELS ABOVE MET DEPICTIONS...AND 
UPSTREAM TEMPS FIT WELL WITH THIS. TOMORROW NIGHT...MAV FITS WELL 
WITH EXPECTED 850 TEMPERATURES...AND COOLER MET IS UNLIKELY AS WEAK 
WARM ADVECTION BEGINS IN EARNEST OVERNIGHT. FOR WEDNESDAY...WEAK 
WARM ADVECTION CONTINUES...BUT THE OPERATIONAL MAV IS THE HIGHEST 
END OF THE ENSEMBLES AND THIS SEEMS UNLIKELY...SO USED A MIX OF THE 
OPERATIONAL AND ENSEMBLE AVERAGES.

&&

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

&&

$$

PUBLIC...NIELD
AVIATION...JAS