FXUS63 KLMK 251110
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
610 AM EST WED NOV 25 2009

...UPDATED AVIATION DISCUSSION...

.SHORT TERM (TODAY AND TONIGHT)...

A COLD FRONT IS PASSING THROUGH THE REGION...TAKING LIGHT RAIN 
SHOWERS EASTWARD WITH IT. THESE SHOWERS WILL REMAIN SCATTERED OVER 
THE BLUEGRASS REGION FOR THE NEXT COUPLE OF HOURS BEFORE COMPLETELY 
EXITING THE CWA. STRATUS DECK WILL TRAIL THE COLD FRONT THOUGH...BUT 
BY SUNRISE...MOST PLACES EXCEPT OVER THE NRN CWA WILL BE CLOUD FREE.

THE UPPER LOW ASSOCIATED WITH THE FRONTAL PASSAGE IS SPINNING OVER 
THE IA/IL BORDER. THIS HAS A LARGE AREA OF OVERCAST SKIES FROM 
CENTRAL MISSOURI NORTHWARD. THESE CLOUDS WILL MAKE THEIR WAY INTO 
OUR CWA BY MIDDAY...MAINLY AFFECTING THE NORTHERN THIRD OF THE CWA. 
THIS WILL GREATLY IMPACT HIGH TEMPS TODAY...SO WENT MORE TOWARD GFS 
RAW TEMPS FOR HIGHS WITH TEMPS RANGING FROM 50 DEGREES NORTH TO 
55-56 SOUTH. WINDS COULD BE GUSTY AT TIMES TODAY...ESPECIALLY THIS 
MORNING AHEAD OF THE UPPER-LOW CLOUDS.

THIS EVENING INTO THE OVERNIGHT HOURS...ANOTHER TROUGH CURRENTLY 
OVER ND WILL DIVE SE...USHERING IN COLD CANADIAN AIR (SEE LONG TERM 
DISCUSSION). ALTHOUGH IT WILL NOT GENERATE MUCH QPF...THIS TROUGH 
COULD SQUEEZE OUT ISOLATED RAIN SHOWERS MAINLY ACROSS THE NORTHERN 
CWA. AFTER MIDNIGHT AND TOWARDS 12Z THURSDAY WILL BE THE BEST CHANCE 
OF RAIN SHOWERS...THOUGH TOWARDS SUNRISE ON THANKSGIVING ALTHOUGH 
SFC TEMPS WILL NOT BE COLD ENOUGH...TEMPS ALOFT COULD BE COLD ENOUGH 
TO HELP MIX A FEW SNOW FLAKES IN WITH THE COLD RAIN SHOWERS. THESE 
SHOWERS WILL BE ISOLATED AND LIGHT. OVERNIGHT LOWS WILL BE IN THE 
MID 30S N TO AROUND 40 ACROSS THE BLUEGRASS.

.LONG TERM (THURSDAY - WEDNESDAY)...

TWO MAIN WEATHER SYSTEMS WILL AFFECT THE FORECAST AREA THROUGH THE 
LONG TERM. FIRST OFF IS THE UPPER LEVEL LOW WHICH WILL BE CENTERED 
OVER INDIANA THURSDAY MORNING AND HOW THIS WILL AFFECT THE WEATHER 
FOR THANKSGIVING. MODELS ARE IN GOOD AGREEMENT WITH THIS SYSTEM FOR 
THE FIRST TWENTY-FOUR TO THIRTY-SIX HOURS OF THE FORECAST. THURSDAY 
MORNING SCATTERED LIGHT SHOWERS WILL BE AFFECTING MAINLY NORTH 
CENTRAL KENTUCKY AND SOUTHERN INDIANA. THESE SHOWERS WILL INCREASE 
THROUGHOUT THE DAY AS THE UPPER LEVEL LOW SWINGS ACROSS THE OHIO 
VALLEY. THOUGH SHOWERS WILL BE MOST NUMEROUS OVER NORTHERN PORTIONS 
OF THE FORECAST AREA THEY ARE NOT EXPECTED TO BE CONTINUOUS 
THROUGHOUT THE DAY. AT 850 MB MUCH COLDER AIR CAN BE SEEN DIVING 
DOWN ACROSS THE FORECAST AREA ON THE BACKSIDE OF THE LOW. THIS 
COMBINED WITH CLOUDS AND PRECIPITATION WILL HOLD TEMPERATURES IN THE 
LOWER TO MID 40S DURING THE DAY ON THURSDAY.

OVERNIGHT A SECOND SHOT OF REINFORCING COLD AIR WILL BE DIVING 
AROUND THE UPPER LOW. PRECIPITATION LOOKS TO BEGIN TO CHANGE OVER TO 
A SNOW/RAIN MIX BY THURSDAY EVENING AND TO ALL SNOW AFTER MIDNIGHT. 
THE MODELS HAVE CONTINUED TO SPEED UP THE EXIT OF THIS SYSTEM. THE 
MAIN BULK OF THE PRECIPITATION WILL BE MOVING OUT BY THE TIME THE 
CHANGEOVER TO ALL SNOW OCCURS...SO EXPECT ONLY LIGHT SNOW SHOWERS  
WITH NO ACCUMULATION DUE TO A WARM GROUND. TEMPERATURES WILL FALL TO 
AT OR BELOW FREEZING AT MOST LOCATIONS BY THURSDAY MORNING SO SOME 
ICING ON BRIDGES AND OVERPASSES MAY BE POSSIBLE.

ALL PRECIPITATION LOOKS TO END OVER THE BLUEGRASS BY MID DAY ON 
FRIDAY. HOWEVER WITH CLOUD COVER AND NORTHWESTERLY UPPER LEVEL FLOW 
CONTINUING TEMPERATURES WILL REMAIN ON THE COOL SIDE IN THE LOWER 
40S. SURFACE HIGH PRESSURE WILL BEGIN RIDGING IN ON FRIDAY NIGHT. 
THIS WILL CLEAR OUT CLOUDS AND WITH WINDS BECOMING SOUTHERLY 
TEMPERATURES WILL REBOUND NICELY TO NEAR SEASONAL NORMS ON SATURDAY 
AND SUNDAY.

THE NEXT SYSTEM TO AFFECT THE AREA WILL BRING PRECIPITATION 
BEGINNING POSSIBLY SUNDAY AFTERNOON TO AREAS WEST OF I-65 AND SPREAD 
EASTWARD AS A SURFACE LOW FORMING OVER THE ARKLATEX BEGINS TO EJECT 
NORTHEASTWARD. GFS/ECMWF HAVE WIDELY DIFFERENT SOLUTIONS TO THE 
UPPER LEVEL PATTERN FOR THIS SYSTEM WITH THE LATEST RUN OF THE GFS 
SIGNIFICANTLY DEEPENING AN UPPER LEVEL LOW AND TAKING IT ON A TRACK 
FROM TEXAS UP THROUGH KY WHILE THE ECMWF IS LESS AGGRESSIVE WITH THIS 
FEATURE THAN IN PREVIOUS RUNS. GIVEN THE DIFFERENCES...HAVE NOT MADE 
ANY CHANGES TO THE FORECAST FOR MON/TUES. EITHER WAY IT LOOKS LIKE 
WE COULD SEE SOME DECENT RAIN FROM THIS SYSTEM MONDAY AND TUESDAY 
WITH THE POSSIBILITY OF A RAIN/SNOW MIX DURING THE OVERNIGHT HOURS.

&&

.AVIATION (12Z TAF ISSUANCE)...

COLD FRONTAL BOUNDARY IS PUSHING THROUGH LEX AT THE MOMENT...AND 
SKIES SHOULD BE CLEARING OUT THERE BY 12Z. MORE LOW VFR/HIGH MVFR 
CIGS ASSOCIATED WITH THE TRAILING UPPER LOW SPINNING OVER CENTRAL IL 
ARE PUSHING INTO THE EVV/HNB AREA RIGHT NOW. THESE CIGS WILL AFFECT 
SDF JUST AFTER 12Z...THOUGH THE CLOUDS WILL WAVER BETWEEN BKN AND 
SCT. BUT BY MIDDAY...THE BKN-OVC SKIES ON THE BACKSIDE OF THE UPPER 
LOW SHOULD FILTER INTO THE SDF AND LEX TERMINALS...PERHAPS AS FAR 
SOUTH AS BWG. THESE CIGS MAY DIP INTO THE LOW MVFR RANGE...IF NOT 
LOWER AT TIMES. WILL KEEP MVFR CIGS AT SDF AND LEX...WITH SCATTERED 
CLOUDS AT BWG. 

THESE CLOUDS WILL STICK AROUND FOR THE BETTER PART OF THE DAY BEFORE 
ANOTHER UPPER LOW FROM THE NRN PLAINS DIVES QUICKLY SEWD TOWARD US. 
THIS WILL BRING ISOLATED VERY LIGHT RAIN SHOWERS TO THE 
REGION...WITH THE BEST CHANCE AT SDF AFTER 05Z. TOWARDS 12Z 
THURSDAY...A FEW SNOW FLAKES COULD MIX IN. BUT BECAUSE OF THE LACK 
OF COVERAGE AND LIGHT INTENSITY OF THE SHOWERS...WILL CONTINUE THE 
VCSH WORDING AT SDF AND POSSIBLE LEX.

WINDS WILL BE OUT OF THE SOUTHWEST FOR THE MOST PART...AND GUSTY AT 
TIMES ESPECIALLY WHERE CLOUD BREAKS OCCUR. DURING THE LAST 12 HOURS 
OF THE TAF PERIOD...WINDS WILL VEER AND BECOME MORE WESTERLY...AND 
STILL GUSTY.

&&

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

$$

SHORT TERM........AL
LONG TERM.........EES
AVIATION..........AL