FXUS63 KIND 260449
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
1150 PM EST FRI DEC 25 2009

AVIATION...DISCUSSION FOR 26/06Z TAFS
A BAND OF SNOW WILL TRACK ACROSS WEST CENTRAL AND NORTH CENTRAL 
INDIANA THROUGH 08Z OR 09Z WITH THE WORST OF IT TRACKING BETWEEN 
KLAF AND KIND.  BRIEF IFR VISIBILITIES ARE POSSIBLE INSIDE THIS 
BAND...BUT SINCE TAF SITES ARE GETTING THE EDGE WILL FORECAST A FEW 
HOURS OF OCCASIONAL MVFR VISIBILITIES. 

THIS BAND OF SNOW WILL MOVE OUT OF OUR REGION BY 09Z AND A DRY SLOT 
PUSHING INTO OUR REGION SHOULD PRODUCE A PERIOD OF VFR CONDITIONS 
WITH CIGS 35 HUNDRED TO FIVE THOUSAND FEET LATE TONIGHT AND EARLY 
SATURDAY.  MODELS BRING ANOTHER BAND OF SNOW SHOWERS ACROSS OUR 
REGION BY MIDDAY SATURDAY AND CONDITIONS MAY DROP BACK TO MVFR 
CATEGORY.  

STRONG SURFACE LOW WILL REMAIN ACROSS IOWA THROUGH 00Z SUNDAY...THIS 
SYSTEM WILL BEGIN TO OPEN UP AND TRACK TOWARDS THE SOUTHERN GREAT 
LAKES SATURDAY NIGHT.  THIS LOW WILL PRODUCE A MODERATE SOUTHWEST 
FLOW WITH GUSTS IN EXCESS OF 20 KNOTS AT TIMES.

&&

.UPDATE...
A NARROW BAND OF SNOW HAS BEEN MOVING ACROSS SOUTHERN AND CENTRAL
ILLINOIS...CAUSING REDUCED VISIBILITIES. ANTICIPATE THIS BAND WILL
CLIP THE WESTERN COUNTIES OF FORECAST AREA. AS A RESULT...BUMPED
POPS/QPF AMOUNTS UP A BIT ACROSS THOSE COUNTIES. IN
ADDITION...INCREASED TONIGHT/S LOWS ABOUT 2 TO 3 DEGREES. CURRENT
TRENDS ARE FAVORING THE MAV INSTEAD OF MET.

&&

.PREV DISCUSSION... /ISSUED 555 PM EST FRI DEC 25 2009/ 

BIGGEST PROBLEM IS TEMPERATURES. 

MAV LOOKS HIGH TO ME FOR MOST OF FORECAST PERIOD. MET LOOKS BETTER 
BUT STILL NEEDS TO BE CUT. 

LOOKING AT TEMPERATURES UPSTREAM DONT SEE 30S UNTIL YOU GET TO 
ARKANSAS AND ITS SUNNY THERE. ABOVE 30 WILL BE CHALLENGING TOMORROW 
SINCE WE ARE APT TO BE CLOUDY. 

SECOND REASON I DONT LIKE MOS TEMPS IS THE MODELS CONCUR WITH 
THICKNESSES PLUNGING OVER INDIANA BEGINNING OVERNIGHT. MAV TEMPS 
DONT SEEM TO PICK UP ON THIS VERY WELL AND MET DOES NOT AFTER 
TONIGHT....BUT ITS CONSISTENT WITH THE COLD TEMPERATURES THAT SEEM 
TO BE HEADING TOWARD THIS. 

BOTTOM LINE IS I CAN LIVE WITH MET TONIGHT...BUT AFTER THAT I WILL 
CUT IT ABOUT 3 DEGREES INTO MONDAY. 

AT LEAST IT WILL BE COLD ENOUGH SO ANY PRECIPITATION WILL BE SNOW. 
MODELS AGREE WE WILL BE IN DRY SLOT MOST OF TONIGHT WITH MOISTURE 
INCREASING AT MID LEVELS BUT BOUNDARY LAYER STAYING DRY TOWARD. I 
EXPECT FLURRIES FLURRIES DEVELOPING IN MOIST LAYER AND MAKING IT TO 
SURFACE...BUT AGREE WITH GUIDANCE ABOUT LOW CHANCE OF MEASURABLE.

SATURDAY COULD BE GOOD FOR SNOW SHOWERS WITH CYCLONIC FLOW OVR 
LAKES...UNSTABLE BOUNDARY LAYER...AND SOME Q VECTOR DIVERGENCE 
ALOFT. SOME PLACES WILL TRACE OUT...OTHERS WILL MEASURE...BUT THINK 
MOST REPRESENTATIVE FCST WILL BE SNOW SHOWERS LIKELY.

MODELS AGREE FAIRLY WELL ABOUT PRIMARY FIELDS SATURDAY NIGHT THROUGH 
SUNDAY. TO THE EXTENT THEY DIFFER LIKED GFS WHICH WAS MUCH CLOSER TO 
SREF. FOR THE MOST PART ACCEPT MAV POPS SATURDAY NIGHT INTO 
MONDAY...BUT WILL BUMP UP TO 50 PERCENT SUNDAY WITH MODELS SHOWING 
FAIRLY GOOD QVECTOR DIVERGENCE ALOFT. 

BUFKIT SUPPORTS SOME GUSTS SATURDAY WHICH MAKES SENSE AS COLD 
ADVECTION ALOFT PROMOTES DOWNWARD MIXING. CLOUDY TO MOSTLY CLOUDY 
THROUGH SUNDAY NIGHT UNDER CYCLONIC FLOW. MAY GET SOME BREAKS MONDAY 
AS HIGH STARTS TO BUILD IN. 

&&

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

&&

$$

PUBLIC...KWIATKOWSKI
AVIATION...JH
UPDATE...TDUD