FXUS63 KIND 021046
AFDIND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
546 AM EST WED DEC 2 2009

.AVIATION...DISCUSSION FOR 02/12Z TAFS

VFR CONDITIONS EARLY IN THE PERIOD WILL GIVE WAY TO MVFR FROM SOUTH 
TO NORTH ACROSS THE AREA FROM 18-21Z OR SO AS AN AREA OF LOW 
PRESSURE MOVES INTO THE OHIO VALLEY. RAIN WILL BEGIN BEFORE 
THAT...BUT AT THE ONSET OF RAIN CEILINGS WILL GRADUALLY LOWER 
THROUGH THE VFR RANGE. MODELS ARE STILL HINTING AT IFR CONDITIONS 
DEVELOPING AS THE LOW GETS CLOSER TO THE OHIO RIVER TOWARD 00Z. 
STILL NOT CONFIDENT OF THIS WITH THE WINDS INCREASING AND PROMOTING 
MIXING OF THE LOWER ATMOSPHERE. HOWEVER SINCE BMG IS PRONE TO LOWER 
CEILINGS AM MORE CONFIDENT TO GO IFR THERE BY 00Z. ELSEWHERE WILL 
LOWER TO LOW MVFR. RAIN WILL CONTINUE INTO THE EVENING WITH 
VISBILITIES IN THE MVFR RANGE. AS THE LOW MOVES OFF TO THE EAST 
AFTER 06Z PRECIPITATION WILL DIMINISH...BUT LOW MVFR CEILINGS STILL 
WILL HANG AROUND THROUGH THE END OF THE PERIOD. WOULD NOT RULE OUT 
SOME SNOW MIXING IN WITH ANY LEFTOVER RAIN AFT 06Z.

CONCERNING WINDS...THE BACKING TREND WILL CONTINUE AS WINDS GO FROM 
EAST TO NORTH TO NORTHWEST DURING THE PERIOD. AS THE SURFACE LOW 
GRADUALLY INTENSIFIES...EXPECT SOME GUSTS THIS AFTERNOON AND 
ESPECIALLY OVERNIGHT...WHEN THE GUSTS COULD APPROACH 25KT.

&&

.DISCUSSION...
A 999 MB LOW PRESSURE SYSTEM WAS ALONG THE LOUISIANA COAST...WHILE 
ANOTHER LOW PRESSURE SYSTEM WAS OVER SOUTHERN LAKE SUPERIOR.  A COLD 
FRONT EXTENDED FROM THE LOW ACROSS WISCONSIN TO THE TEXAS PANHANDLE.
WATER VAPOR SATELLITE SHOWED A STRONG UPPER LOW OVER TEXAS...WHILE A 
STRONG UPPER TROUGH WAS DIGGING INTO THE NORTHERN PLAINS.

MAIN FORECAST CONCERNS WILL BE TIMING OF PRECIPITATION LATER 
TODAY...RAIN CHANCES AND HOW QUICKLY IF IT DOES THIS PRECIPITATION 
CHANGES OVER TO SNOW LATER TONIGHT.

MODELS ARE IN VERY GOOD AGREEMENT DURING THE NEXT 24 HOURS AND THEY 
DIVERGE SOME AFTER THAT.  THEY ALL TRACK THE SURFACE LOW FROM 
LOUISIANA TO NEAR LOUISVILLE BY 00Z THURSDAY AND NEAR LAKE ERIE BY 
12Z THURSDAY.  RADAR LOOPS INDICATES A SOLID AREA OF RAIN FROM THE 
TENNESSEE KENTUCKY BORDER AND SOUTHWARD. MODELS SPREAD THIS RAIN 
RAPIDLY NORTHWARD...BUT ARE A TAD SLOWER THAN IN THE PREVIOUS RUN.
I EXPECT RAIN TO REACH OUR FAR SOUTH BY 14-15Z...TO NEAR INDY BY 
17-18Z AND ACROSS OUR NORTH AN HOUR OR TWO LATER.

DEWPOINTS ARE AROUND 30 AND THERE COULD BE QUIET A BIT OF 
EVAPORATIONAL COOLING ONCE THE RAIN BEGINS SO WILL UNDERCUT MOS 
HIGHS 3 TO 5 DEGREES CENTRAL AND SOUTH TODAY.  OUR WARMEST 
TEMPERATURES WILL OCCUR IN THE FAR NORTH AS RAIN WILL BE A BIT 
SLOWER REACHING THERE.

AS THE SURFACE AND UPPER LOW NEAR THE GULF COAST TRACK TOWARDS THE 
GREAT LAKES...MODELS DIG THE STRONG UPPER TROUGH INTO THE UPPER 
MIDWEST.  COLDER WITH THIS NORTHERN SYSTEM SPREADS IN BEHIND THE LOW 
...BUT MODELS HAVE TRENDED A LITTLE SLOWER IN SPREADING THIS COLDER 
AIR ACROSS OUR REGION.

THE 1300 MB 1000-850 THICKNESS MOVES INTO WESTERN INDIANA SHORTLY 
AFTER 06Z AND INTO OUR EAST BY 12Z THURSDAY.  PRECIPITATION WILL BE 
PRIMARILY RAIN OVERNIGHT...BUT IT COULD BECOME MIXED WITH SNOW IN 
OUR WEST BY 06Z AND ELSEWHERE AFTER 09Z.  THERE MAY BE ONE OR TWO 
TENTHS OF AN INCH OF SNOW ACROSS OUR FAR NORTHWEST.  BUT NO 
ACCUMULATION IS EXPECTED ELSEWHERE.

WILL CONTINUE A CHANCE OF FLURRIES THURSDAY AS SOME WRAP AROUND 
MOISTURE MOVES ACROSS OUR REGION. MODELS DROP 850 TEMPERATURES TO 
-10 BY 00Z FRIDAY AND KEEP -10 TO -14 DEGREE VALUES ACROSS OUR 
REGION THURSDAY NIGHT INTO SATURDAY. WILL UNDERCUT MOS TEMPERATURES 
A FEW DEGREES.

HIGH PRESSURE WILL DOMINATE OUR WEATHER THIS WEEKEND AND 
TEMPERATURES WILL MODERATE SOME SUNDAY AND MONDAY.  THE GFS AND 
EUROPEAN BRING PRECIPITATION BACK INTO OUR REGION BY THE MIDDLE OF 
NEXT WEEK. 

&&

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

&&

$$

DISCUSSION...JH
AVIATION...CS