FXUS63 KIND 261057
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
557 AM EST SAT DEC 26 2009

.AVIATION...DISCUSSION FOR 26/12Z TAFS.
UPPER LEVEL LOW PRESSURE CONTINUES TO SPIN OVER THE WESTERN GREAT 
LAKES ARLY THIS MORNING. UPPER LEVEL DISTURBANCE AND ASSOCIATED 
SURFACE CONVERGENCE BOUNDARY IS NOW OFF TO THE EAST OF ALL 
TERMINALS. SKIES HAVE BRIEFLY CLEARED AT KBMG AND KIND AS OF 11Z. 
ANY BREAKS SHOULD BE TEMPORARY THIS MORNING WITH LARGE AREA OF 
STRATOCUMULUS ALREADY EXPANDING INTO KHUF AND KLAF THIS MORNING 
AHEAD OF AREA OF SNOW SHOWERS OVER CENTRAL ILLINOIS. CONTINUED LOW 
LEVEL COLD ADVECTION AND SHALLOW INSTABILITY WILL ALLOW FOR QUICK 
EXPANSION TO LOWER CLOUDS ACROSS ALL OF THE TERMINALS BY MIDDAY. 
NEXT UPPER LEVEL DISTURBANCE ROTATING AROUND THE LOW WILL SWING 
THROUGH CENTRAL INDIANA THIS AFTERNOON. WHILE SNOW SHOWERS 
ASSOCIATED WITH THIS FEATURE LIKELY TO IMPACT KLAF AS SOON AS MID 
MORNING...MOST OF THE IMPACTS WILL BE FELT AT THE TERMINALS DURING 
THE AFTERNOON. MVFR CONDITIONS ARE EXPECTED AT ALL SITES EXCEPT 
KBMG. 

IN WAKE OF THE SECOND DISTURBANCE THIS EVENING...SNOW SHOWERS 
SHOULD DECREASE IN COVERAGE BUT CEILINGS WILL LIKELY REMAIN IN MVFR 
CATEGORY. SOUTHERLY WINDS THIS MORNING WILL VEER TO SOUTHWEST FOR 
THE REMAINDER OF THE FORECAST PERIOD. WIND GUSTS UP TO 25KTS ARE 
POSSIBLE FOR MUCH OF THE DAY...WITH GUSTS DIMINISHING IN WAKE OF THE 
SNOW SHOWERS THIS EVENING. ADDITIONAL SNOW SHOWERS ARE LIKELY NEAR 
THE END OF THE FORECAST PERIOD AS UPPER LOW PINWHEELS INTO THE 
REGION FROM THE WEST. THIS WILL IMPACT THE FORECAST AREA ON SUNDAY 
AND WILL BE ADDRESSED IN GREATER DETAIL WITH SUBSEQUENT TAF 
FORECASTS.

&&

.DISCUSSION...DEEP UPPER LOW CENTERED OVER THE MIDWEST EXPECTED TO 
GRADUALLY LIFT OFF TO THE NORTHEAST DURING THE NEXT FEW 
DAYS...EVENTUALLY REACHING THE NEW ENGLAND REGION BY MONDAY EVENING. 
SEVERAL DISTURBANCES WILL BE ROTATING AROUND THE UPPER LOW...KEEPING 
THINGS UNSETTLED THROUGH SUNDAY. MODELS IN GOOD AGREEMENT ON THE 
MAJOR FEATURES. FORECAST FORECAST CENTERS ON POPS.

FOR TODAY...VORTICITY LOBE CURRENTLY PUSHING THROUGH THE LOCAL AREA 
WITH AN ASSOCIATED BAND OF SNOW SHOWERS. BASED ON ITS 
MOVEMENT...SHOULD BE WELL EAST OF THE AREA BY SUNRISE. 
OTHERWISE...MAY NOT SEE TOO MUCH ACTIVITY UNTIL LATER THIS AFTERNOON 
WHEN MODEL DATA INDICATE THE NEXT IMPULSE SHOULD BE APPROACHING 
THE NORTHWESTERN ZONES. WILL CONTINUE WITH CHANCE POPS FOR SNOW 
SHOWERS ALL AREAS WITH THE HIGHEST POPS IN THE NORTHWEST. POCKETS OF 
CLEARING SKIES EARLY THIS MORNING SHOULD BE TEMPORARY...WITH 
INSTABILITY CLOUDS FILLING BACK IN AFTER SUNRISE.

IN THE LATER PERIODS...DISTURBANCE MENTIONED ABOVE SHOULD BE MOVING 
THROUGH TONIGHT...SO WILL CONTINUE WITH CHANCE POPS. STILL 
LOOKS LIKE THE BEST CHANCES OF PRECIPITATION WILL BE ON SUNDAY AS 
THE BULK OF THE UPPER ENERGY PUSHES THROUGH. COULD SEE SOME 
ACCUMULATIONS IN THE 1/2 TO 1 INCH RANGE AT THAT TIME BASED ON QPF 
PROGS OFF THE MODELS. PRECIPITATION THREAT SHOULD END BY SUNDAY 
NIGHT AS UPPER TROUGH PASSES OFF TO THE EAST.

BASED ON LOW LEVEL THICKNESSES...THE GFS MOS HIGHS FOR TODAY MAY BE 
A FEW DEGREES ON THE WARM SIDE. WILL NUDGE THE GUIDANCE DOWN A BIT 
TODAY. REMAINDER OF THE PERIODS LOOK OK FOR THE MOST PART.

&&

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

&&

$$

PUBLIC...JAS
AVIATION...RYAN