FXUS63 KLMK 291518
AFDLMK

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1018 AM EST SUN NOV 29 2009

...FORECAST UPDATE...

SOME MINOR FORECAST ADJUSTMENTS FOR THIS AFTERNOON AND EVENING WERE 
MADE BASED ON CURRENT RADAR TRENDS AND LATEST MODEL RUNS COMING IN. 
PRECIPITATION WAS INCREASING IN COVERAGE ACROSS WESTERN TENNESSEE 
WITH SOME SHOWERS DEVELOPING OVER WESTERN KY AS WELL. THIS ARE OF 
PRECIPITATION WAS MOVING EAST/NORTHEAST AND MAY AFFECT WESTERN 
PORTIONS OF THE FORECAST AREA THIS AFTERNOON WITH LIGHT RAIN. 
THEREFORE...ADDED SOME SLIGHT CHANCE POPS MAINLY WEST OF INTERSTATE 
65 FROM SOUTHERN INDIANA TO THE KY/TN BORDER BEGINNING AT 18Z AND 
INCREASING POPS GENERALLY FROM WEST TO EAST THROUGH THE REMAINDER OF 
THE AFTERNOON AND INTO THE EVENING AS A COLD FRONT APPROACHES THE 
REGION. 

CURRENTLY...THE COLD FRONT WAS LOCATED FROM NEAR CHICAGO TO JUST 
WEST OF SAINT LOUIS TO THE OK/AR STATE LINE. WINDS SPEEDS WILL 
INCREASE THROUGH THE DAY AS THIS FRONT PUSHES SOUTHEAST AND GUSTS TO 
AROUND 20 MPH WERE ALREADY BEING RECORDED AT BOWMAN FIELD IN 
LOUISVILLE AND AT FRANKFORT. MID LEVEL CLOUDS AROUND 8KFT WILL ALSO 
BEGIN TO MOVE INTO WESTERN PORTIONS OF THE FORECAST AREA OVER THE 
NEXT HOUR OR SO AND WORK EASTWARD. GIVEN BKN UPPER LEVEL CLOUDINESS 
AND THE THICKER MID LEVEL DECK HEADED THIS WAY...DECREASED TEMPS A 
DEGREE OR TWO ACROSS THE WEST WHILE KEEPING HIGHS IN THE LOW 60S 
EAST OF INTERSTATE 65.

.SHORT TERM (TODAY - MONDAY)...

A FRONTAL BOUNDARY STRETCHING FROM SOUTHERN LAKE MICHIGAN TO 
NORTHERN TEXAS THIS MORNING WILL BE THE FOCUS FOR PRECIPITATION IN 
THE SHORT TERM PERIOD.  THIS FRONT WILL MOVE EAST TODAY AND BE 
KNOCKING ON OUR DOORSTEP BY THIS EVENING.  EXPECT INCREASING CLOUDS 
AND GUSTY WINDS AHEAD OF THIS SYSTEM.  SW WINDS WILL GUST UP TO 20 
TO 25 MPH TODAY.  HIGH TEMPERATURES ARE EXPECTED TO TOP OUT IN THE 
UPPER 50S OVER SOUTHERN INDIANA TO LOW 60S ELSEWHERE.  WE SHOULD 
START TO SEE A FEW STRAY SHOWERS OVER OUR FAR WESTERN COUNTIES BY 
LATE THIS AFTERNOON/EARLY EVENING.

TONIGHT...THE FRONT WILL PASS THROUGH THE AREA BETWEEN 3Z TO 9Z 
BRINGING WIDESPREAD RAIN.  QPF AMOUNTS WILL GENERALLY RANGE FROM A 
FEW HUNDREDTHS OF AN INCH UP TO A HALF INCH.  COLDER AIR WILL BE 
USHERED IN BEHIND THE FROPA ALLOWING TEMPS TO DROP INTO THE UPPER 
30S OVER SOUTHERN INDIANA TO MID 40S IN THE LAKE CUMBERLAND REGION.

FOR MONDAY...EXPECT ANY STRAY SHOWERS ASSOCIATED WITH THE FROPA TO 
BE OUT OF THE REGION BY EARLY AFTERNOON.  THE COLDER AIR MASS OVER 
OUR FORECAST AREA WILL HOLD HIGH TEMPS STEADY IN THE LOW TO MID 40S 
FOR MONDAY.

.LONG TERM (MONDAY NIGHT - SATURDAY)...

MON NIGHT THROUGH THU...

THE FOCUS THIS PERIOD ON WED AND THU WITH OUR FIRST POTENTIAL WINTER 
SYS POSSIBLY BRINGING MEASURABLE FROZEN PRECIP INTO OUR FA. AS FOR 
NOW...THE BEST CHC AND TIMING FOR MEASURABLE SNOW LOOKS TO BE ABOUT 
AN 8-HR PERIOD FROM 08Z-16Z THU ACROSS OUR NRN FA. DETAILS:

BASED ON HPC INPUT AND RUN TO RUN CONSISTENCY...THE EURO AND 
CANADIAN 00Z RUNS WILL PROVIDE THE MOST INPUT INTO THIS FCST. 

BOTH MID RANGE MODELS START OFF WITH A CUTOFF COLD CORE LOW ACRS 
SCNTRL TEXAS AT 12Z WED...MOVE IT NEWD INTO THE LOWER MS VLY BY WED 
EVE AND TO THE TN VLY 12Z THU. THE CANADIAN IS A BIT MORE W/N WITH 
ITS TRACK. ASSOCIATED SFC LOWS MOVE FROM THE SWRN GULF STATES (LA) 
WED MRNG TO NRN MS WED EVE TO WEST VA-12Z THU. BASED ON GULF 
MOISTURE TRANSPORT/INCREASING SYNPOTIC SCALE LIFT/CONVERGENCE...RAIN 
WILL LIKELY OVERSPREAD OUR FA WED AFTN AND POSSIBLY CHANGE TO SNOW 
(BASED ON THERMAL PROFILES)ACRS OUR NWRN/NRN COUNTIES IN THE 08Z-12Z 
TIME FRAME AS SFC LOW MOVES FROM EKY INTO WEST VA. THIS TRANSITION 
WOULD CONTINUE NW TO SE AS COLD AIR CONTINUES TO WRAP INTO THE 
SYSTEM. 

TEMPS ACRS OUR NRN FA...WHERE SNOW COULD BE FALLING...WOULD LIKELY 
BE IN THE LOWER/MID 30S...A BIT WARM TO CAUSE MAJOR PROBS. CERTAINLY 
WE WILL MONITOR THIS SYS CLOSELY AS ITS GETS NEARER. FOR NOW...WILL 
INCREASE POPS FOR WED AFTN TO LIKELY...AT LEAST OVER THE SRN 2/3RDS 
OF OUR FA AND CONTINUE INTO EARLY WED NIGHT. AFTERWARD...WILL LEAVE 
CHC POPS FOR EARLY THU MRNG INTO MIDDAY WITH RAIN OR SNOW WORDING. 
TOO EARLY TO GO WITH HIGHER POPS AND A DEFINITE PRECIP TRANSITION 
WITH THE NAM AND ESPECIALLY THE GFS NOT ON BOARD WITH THIS SCENARIO.

&&

.AVIATION (12Z TAF ISSUANCE)...

VFR CONDITIONS WILL BE EXPECTED FOR THE FIRST 12 HRS OF THIS TAF 
PERIOD. A COLD FRONT WILL APPROACH THE AREA TONIGHT.  AHEAD OF THE 
FRONT...THE SFC PRESSURE GRADIENT WILL INCREASE TODAY CAUSING SW 
WINDS TO GUST UP TO 18 TO 22 KTS THIS AFTERNOON AND EARLY EVENING.  
MID AND UPPER LEVEL CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON 
ALSO.  FOR TONIGHT...WE SHOULD SEE VCSH AHEAD OF THE FRONT THROUGH 
ABOUT 3Z-6Z. AROUND OR AFTER 6Z FLIGHT CONDITIONS WILL DROP INTO THE 
MVFR CAT FOR CIGS/VSBYS AS MORE WIDESPREAD LIGHT TO MODERATE 
RAINFALL ENTERS THE AREA AND PERSISTS THROUGH THE MORNING HOURS. IT 
SHOULD BE NOTED THE IFR CIGS ARE NOT OUT OF THE QUESTION ACCORDING 
TO MET MOS GUIDANCE...HOWEVER WILL REMAIN OPTIMISTIC AT THIS POINT. 
THE FROPA WIND SHIFT TO NW SHOULD OCCUR AT THE VERY END OF THIS TAF 
PERIOD IN THE 10Z-12Z TIME FRAME TOMORROW MORNING.

&&

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

$$

UPDATE.........LS
SHORT TERM.....AML
LONG TERM......DK
AVIATION.......AML