FXUS63 KLMK 141951
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
248 PM EST MON DEC 14 2009

.SHORT TERM (TONIGHT AND TUESDAY)...

SOUTHWEST 500MB FLOW ACROSS THE LOWER OHIO VALLEY WILL TRANSITION TO 
A MORE ZONAL FLOW AS A TROUGH MOVES ACROSS THE WESTERN GREAT LAKES 
TOMORROW AFTERNOON. 

AT THE SURFACE...LOW PRESSURE NOW OVER SOUTHERN MICHIGAN WILL 
QUICKLY MOVE EAST ACROSS NEW ENGLAND BY EARLY WEDNESDAY. ARCTIC AIR 
WILL INVADE THE LOWER OHIO VALLEY TOMORROW. THIS AIRMASS IS SHALLOW 
BUT STILL STRONG...HAVING DROPPED TEMPERATURES AT PONCA CITY 
OKLAHOMA 27 DEGREES IN THREE HOURS EARLIER THIS MORNING. EARLIER 
THIS AFTERNOON AT 2 PM THE FRONT WAS RIGHT OVER ST LOUIS...WITH A 20 
DEGREE DROP JUST BEHIND THE BOUNDARY. THIS FRONT WILL MOVE SOUTHEAST 
OF THE OHIO RIVER AROUND MIDNIGHT. 

FORECAST SOUNDINGS SHOW SATURATION ONLY UP TO AROUND 4 THOUSAND FEET 
OR SO DURING FRONTAL PASSAGE. EXPECT A DRY OVERNIGHT...WITH ONLY 
SOME SPRINKLES OR DRIZZLE FOR A COUPLE OF HOURS BEHIND THE FRONT. 

THIS EVENING WILL STAY QUITE MILD UNTIL DARK. MOST AREAS WILL STAY 
PARTLY CLOUDY UNTIL EARLY EVENING. CLOUDS WILL THICKEN BY MID 
EVENING ACROSS SOUTHERN INDIANA AND BECOME CLOUDY BY THE EARLY 
MORNING HOURS. WINDS SHOULD SWITCH TO THE WEST AFTER FRONTAL PASSAGE 
AND THEN TO THE NORTHWEST BY DAYBREAK. 

TEMPERATURES SHOULD STEADILY FALL TOMORROW MORNING...EVEN THROUGH 
THE LATE MORNING HOURS AS MODIFIED ARCTIC AIR ARRIVES. WITH CLEARING 
EXPECTED DURING THE AFTERNOON...TEMPERATURES MAY RISE A COUPLE OF 
DEGREES...BUT WILL STILL STRUGGLE TO EXCEED THE UPPER 30S.

WINDS WILL REMAIN FROM THE NORTHWEST AT 10 TO 15 MPH DURING THE 
AFTERNOON...MAKING THE AFTERNOON SEEM BRISK.

.LONG TERM (TUESDAY - SUNDAY)...

TUE NGT THRU THU NGT...

A DRY...COLD PERIOD.

LONGWAVE TROF WILL BE EAST OF OUR FA AT THE START OF THIS PERIOD 
WITH NW FLOW DOMINANT AFTERWARD. SKIES WILL HAVE CLEARED BY THEN 
WITH COLD HIGH PRESSURE POSITIONED OVER THE MID/UPPER MS VLY. THE 
HIGH WILL REACH THE LOWER OHIO VALLEY WED EVE AND THE TN 
VLY/NORTHERN GULF STATES THU EVE. SKIES SHUD CONTINUE MAINLY CLR 
THRU WED NIGHT WITH A COMBO OF SCANT MOISTURE AND SUBSIDING AIR. 
SOME CLDS SHUD MOVE IN FOR THU AND THU NIGHT(OF THE HIGH/MID LEVEL 
VARIETY)AS THE NEXT COLD FRONT TAKES SHAPE UPSTREAM OF OUR FA.

OUR CURRENT FCST STRONGLY FAVORS THE NAM MET MOS WITH COLDER TEMPS  
THAN GFS MOS THRU MUCH OF THE PERIOD. THIS LOOKS GOOD BASED ON THE 
POST FRONTAL AMS UPSTREAM AND TRAJECTORIES. 
  
FRI THRU MON...

THIS IS A LOW CONFIDENCE FCST WITH DIVERGING MODELS/MUCH UNCERTAINTY 
...ESPECIALLY FOR SUN AND MON...WHEN WE WILL BASICALLY GO WITH AN 
HPC FCST...EXCEPT COLDER TEMPS FOR SUN. 

THIS FCST FAVORS PRIMARILY THE CANADIAN MODEL FOR FRI/SAT AND HPC 
FOR SUN/MON WITH SUBTLE ADJUSTMENTS AS NOTED ABOVE. 

WNW UPR LEVEL FLOW SHUD PREVAIL THRU MUCH OF THE PERIOD WITH TEMPS 
TRENDING DOWNWARD TO MUCH BELOW NORMAL BY SUN/MON. WILL KEEP LOW CHC 
POPS FOR THE FRI NIGHT THRU SAT NIGHT PERIOD WITH REINFORCING SHOTS 
OF COLDER AIR FRI NIGHT AND SAT AS WEAK LOW PRES MOVES PRIMARILY TO 
OUR NORTH WITH TRAILING CDFNTS MOVG ACRS OUR FA. PROGGED DEEPEST 
MOISTURE APPEARS TO BE ON SAT AS LOW PRES PULLS OFF TO OUR NE WITH 
SPOKES/TROFS OF LOW PRES ROTATING ON THE BACKSIDE. AT THAT TIME...
A SHRTWV TROF IS FCST TO AMPLIFY ACRS THE LOWER OH VLY.  

BY SUN INTO MON...WILL GO WITH A DRY AND COLD FCST AS CANADIAN HI 
PRES DROPS SWD INTO OUR NATIONS MID SECTION AND GRADUALLY SPREADS 
EAST.

&&

.AVIATION (18Z TAF ISSUANCE)...

CEILINGS WILL VARY BETWEEN SCATTERED AND BROKEN WITH STRATO-CU 
LIFTING TO BETWEEN 2 AND 3 THOUSAND FEET THROUGH 00Z FOR LEXINGTON 
AND BOWLING GREEN. BWG WILL BE MOST LIKELY TO CLEAR OUT TO SCATTERED 
BETWEEN 18 AND 00Z. 

SDF MAY BRIEFLY CLEAR OUT TO SCATTERED BETWEEN 18 AND 22Z...BUT 
AFTER 22Z...BECOME OVERCAST. 

SOUTHWEST WINDS BETWEEN 10 AND 15 MPH WITH GUSTS UP TO 25 MPH WILL 
CONTINUE THROUGH 22Z AT ALL TAF SITES...THEN DIMINISH SLIGHTLY. A 
SHARP COLD FRONT WILL MOVE SOUTHEAST ACROSS SDF AROUND 05Z AND 
THROUGH LEX AND BWG IN THE 06-07Z TIME FRAME. CEILINGS WILL LOWER 
ALONG AND BEHIND THIS FRONT FOR A FEW HOURS TO MVFR LEVELS...AND 
WINDS WILL SHIFT TO THE WEST AND EVENTUALLY TO THE NORTHWEST BEHIND 
THE FRONTAL PASSAGE. A FEW SPRINKLES MAY DEVELOP FOR A COUPLE OF 
HOURS ALONG AND BEHIND THIS FRONT.

MVFR CIGS WILL CONTINUE THROUGH 12Z TUESDAY BEFORE SCATTERING OUT IN 
THE AFTERNOON. 

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&

$$

SHORT TERM........JSD
LONG TERM.........11