FXUS63 KIND 261704
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1200 PM EST SAT DEC 26 2009

.AVIATION...DISCUSSION FOR 26/18Z TAFS

AREA OF LIFT ACROSS ILLINOIS WILL DRIFT EAST TOWARD THE TAF SITES 
THIS AFTERNOON. BEST FORCING LOOKS TO BE NORTH OF THE AREA...SO KLAF 
HAS THE BEST CHANCE TO SEE SNOW. WILL CONTINUE TO GO MVFR CEILINGS 
AND VISIBILITIES IN LIGHT SNOW FOR SEVERAL HOURS LATE THIS AFTERNOON 
INTO THIS EVENING THERE. CHANCES DIMINISH TO THE SOUTH...BUT LOOKING 
UPSTREAM THERE ARE STILL SOME SITES WITH MVFR CONDITIONS IN LIGHT 
SNOW...SO WILL ALSO KEEP THESE CONDITIONS IN THE FORECAST AT HUF/IND 
FOR A FEW HOURS IN A SIMILAR TIME PERIOD. WILL KEEP VISIBILITIES A 
LITTLE HIGHER AT THOSE SITES THOUGH. BMG LOOKS TO BE FAR ENOUGH 
SOUTH FOR NOTHING OTHER THAN A CONTINUED VCSH MENTION.  OUTSIDE THE 
SNOW SHOWERS EXPECT LOW VFR CEILINGS. WINDS WILL CONTINUE TO GUST 
OVER 20KT INTO THE EVENING HOURS AT ALL SITES.

AFTER FIRST WAVE MOVES PAST...THE OVERNIGHT SHOULD BE DRY FOR THE 
MOST PART. MORE WIDESPREAD SNOW LOOKS TO IMPACT THE TAF SITES AFTER 
12Z SUNDAY WITH LOW MVFR CONDITIONS FORECAST AT THE MOMENT. COULD BE 
IFR CONDITIONS IN HEAVIER SNOW SHOWERS...BUT THAT IS TOO FAR OUT TO 
PUT IN THE TAFS AT THE MOMENT.

&&

.UPDATE...

UPDATED FORECAST TO REFLECT CURRENT SKY COVER AS EASTERN HALF OF 
FORECAST AREA HAS BECOME MOSTLY CLEAR. CLOUDS SHOULD REDEVELOP THIS 
MORNING IN THE COLD ADVECTION AND RETURN EVERYONE TO MOSTLY CLOUDY 
SKIES. ALSO DELAYED CHANCES FOR SNOW SHOWERS ACROSS EASTERN AREAS 
UNTIL MAINLY THE AFTERNOON AS IT LOOKS TO TAKE A WHILE FOR THE UPPER 
LEVEL ENERGY TO ROTATE IN.

&&

.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. 

&&

$$

UPDATE...CS
PUBLIC...JAS
AVIATION...CS