FXUS63 KLMK 232315
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
615 PM EST WED DEC 23 2009
...UPDATE TO AVIATION...
.PREV DISCUSSION... /ISSUED 244 PM EST WED DEC 23 2009/
SHORT TERM (TONIGHT AND THURSDAY)...
A WARM FRONT WAS MOVING ACROSS THE WESTERN PORTION OF KENTUCKY AT
19Z WITH SCATTERED SHOWERS MOVING NORTH ACROSS WESTERN TENNESSEE.
THE WARM FRONT EXTENDED FROM AN AREA OF LOW PRESSURE DEEPENING OVER
OKLAHOMA AND TEXAS. A FEW SHOWERS WILL CONTINUE TO BE POSSIBLE...
MAINLY WEST OF I-65 LATE THIS AFTERNOON AS THE FRONT MOVES NORTH OF
THE AREA.
PRECIPITATION DOES NOT LOOK VERY LIKELY TONIGHT AND THURSDAY MORNING
AS SOME LOW LEVEL DRY AIR INTRUDES INTO THE AREA AS LOW LEVEL WINDS
BACK TO THE SOUTHEAST. WE WILL KEEP POPS IN THE CHANCE CATEGORY
OVERNIGHT AND THEN GRADUALLY INCREASE POPS ACROSS THE FORECAST AREA
DURING THE DAY THURSDAY. A FEW ELEVATED THUNDERSTORMS MAY DEVELOP
LATE IN THE DAY ACROSS THE SOUTHWEST PORTION OF THE FORECAST AREA
AND WE HAVE MENTIONED THUNDER THERE.
LOW LEVEL WINDS WILL BEGIN TO INCREASE LATE IN THE DAY THURSDAY BUT
WILL REMAIN BELOW ADVISORY CRITERIA. THE STRONGEST WINDS WILL OCCUR
AFTER THE END OF THIS FORECAST PERIOD.
TEMPERATURES TONIGHT WILL FALL INTO THE 30S AND 40S WITH HIGHS
THURSDAY FROM THE UPPER 40S TO MID 50S.
LONG TERM (THURSDAY NIGHT - WEDNESDAY)...
THE ONGOING EXTENDED FORECAST REMAINS FAIRLY UNCHANGED WITH SOME
SLIGHT CHANGES TO POPS AND SKY COVER TO ACCOUNT FOR TIMING CHANGES
IN BRINGING THE FRONT/DRY SLOT THROUGH THE REGION.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...
THE SURFACE LOW ON THURSDAY NIGHT WILL BE CENTERED OVER SOUTHWEST
MISSOURI. MOISTURE WILL CONTINUE TO STREAM INTO THE AREA ALONG WITH
WARM TEMPERATURES AS THE LOW MOVES NORTHWARD OVERNIGHT. THIS WILL
BRING VERY EFFICIENT RAINFALL RATES TO THE REGION EARLY THURSDAY
EVENING WITH ANOTHER HALF INCH TO ONE INCH OF PRECIP POSSIBLE
OVERNIGHT. BREEZY CONDITIONS WILL ALSO CONTINUE WITH LOW LEVEL JET
WINDS AROUND 50 TO 70 KTS NOSING INTO THE REGION. HAVE CONTINUED TO
LEAVE THE MENTION OF THUNDER OUT OF THE FORECAST BUT CAN NOT RULE
OUT ONE OR TWO STRIKES GIVEN THE DYNAMIC NATURE OF THIS SYSTEM
DESPITE A LACK IN ANY INSTABILITY...ELEVATED OR OTHERWISE.
BY FRIDAY MORNING A DRY SLOT STARTS TO WRAP UP INTO WESTERN AND
CENTRAL KENTUCKY AND WILL LEAVE MUCH OF THE REGION UNDER THIS DRY
SLOT THROUGH MOST OF FRIDAY. THEREFORE LOWERED CLOUD
COVER...ESPECIALLY ACROSS THE SOUTH AND TAPERED OFF PRECIP A LITTLE
QUICKER THAN PREVIOUSLY INDICATED IN THE FORECAST.
TEMPERATURES WILL REMAIN WELL ABOVE FREEZING THURSDAY NIGHT AND
FRIDAY SO ALL PRECIPITATION WILL CONTINUE TO BE RAINFALL WITH LOWS
THURSDAY IN THE 40S AND HIGHS FRIDAY IN UPPER 40S TO NEAR 50.
HOWEVER...HIGHS ON FRIDAY WILL LIKELY BE NEAR SUNRISE AS COLDER AIR
BEGINS TO FILTER INTO THE REGION AND TEMPS WILL LIKELY FALL
THROUGHOUT THE DAY AND DROP INTO THE 30S BY 00Z SATURDAY. FRIDAY
NIGHT TEMPERATURES WILL BE COLD ENOUGH FOR SNOW BUT LIKELY THE AREA
WILL ONLY SEE FLURRIES OR VERY LIGHT SNOW SHOWERS AS A LARGE AREA OF
SUBSIDENCE MOVES INTO THE REGION AND ONLY LOW LEVEL MOISTURE IN
AVAILABLE WITH A DECREASING JET AVAILABLE TO GENERATE LIFT.
SATURDAY THROUGH MONDAY...
THE LOW WILL BASICALLY SIT OVER NORTHERN MO/WESTERN IL THURSDAY
NIGHT THROUGH FRIDAY NIGHT BEFORE TREKKING EASTWARD ON SATURDAY AND
PUSHING THE DRY SLOT OFF INTO THE VIRGINIAS. SKIES WILL BECOME
CLOUDY AGAIN AND TEMPERATURES WILL REMAIN COLDER AS THE LOW TRACKS
INTO THE LAKE MICHIGAN REGION. BY SUNDAY THE LOW WILL LIFT INTO THE
UPSTATE NY REGION AND WHILE TEMPERATURES WILL STILL REMAIN COOL
SKIES WILL BEGIN TO CLEAR INTO MONDAY. EXPECTED HIGHS MAINLY IN THE
30S AND LOWS IN THE 20S SATURDAY THROUGH MONDAY.
TUESDAY AND WEDNESDAY...
AN UPPER LEVEL RIDGE WILL MOVE INTO THE REGION TUESDAY AHEAD OF
ANOTHER LOW PRESSURE SYSTEM IN THE SOUTHERN PLAINS AND BRING WARMER
TEMPERATURES TO CENTRAL KY AND SOUTHERN IN. MOISTURE WILL INCREASE
ON SOUTHWEST FLOW AND SKIES WILL ONCE AGAIN BECOME OVERCAST BY
TUESDAY NIGHT BUT EXPECT CONDITIONS TO REMAIN DRY AT THIS TIME.
AVIATION (00Z TAF ISSUANCE)...
OHIO VALLEY AND CENTRAL KENTUCKY CONTINUES TO BE A SPECTATOR TO THE
MAJOR STORM DEVELOPING OVER THE CENTRAL U.S. RADAR DISPLAY OF
PRECIPITATION OVER SOUTHERN 1/3 OF FORECAST AREA IS OVERDONE AS MOST
OF THE REFLECTIVITY SHOWN IS ALOFT WITH LITTLE OR NO RAIN REACHING
THE GROUND. DEWPOINT DEPRESSIONS REMAIN IN THE 10-15 DEGREE RANGE
WITH DEWPOINGS IN THE 30S ACROSS THE AREA...AND UPSTREAM TO THE
SOUTHEAST. WITH SLIGHT DOWNSLOPE OF THESE WINDS...PRECIP WILL HAVE
TO FALL FOR A CONSIDERABLE LENGTH OF TIME TO JUICE UP THE LOW LEVEL
ENOUGH FOR RAIN TO REACH THE GROUND.
SURFACE PRESSURE GRADIENT RELAXES FROM WEST TO EAST ACROSS KY AT
21Z...AND WHILE SOME TIGHTENING IS EXPECTED...THIS WILL NOT OCCUR
UNTIL LATE IN THE FORECAST PERIOD. OVERNIGHT WINDS WILL REMAIN IN
THE 6-9 KT RANGE...WHICH...ALONG WITH DRY SURFACE AIR...WILL PREVENT
ANY CHANCE OF VSBY REDUCTION FROM FOG AT ALL TAF SITES. CIGS COULD
WANDER INTO MVFR RANGE BRIEFLY OVERNIGHT...BUT WILL BE MORE LIKELY
TOWARD END OF FORECAST TIME FRAME.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........JA
LONG TERM.........LMS
AVIATION..........JBS
