FXUS63 KLMK 151040
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
540 AM EST TUE DEC 15 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (TODAY AND TONIGHT)...
CURRENTLY...THE COLD FRONT HAS MOVED THROUGH THE FORECAST AREA AND
WINDS HAD SHIFTED TO THE NORTHWEST. SOME LOWER CLOUDS WERE ALSO
MOVING INTO THE REGION AND THEY WILL STICK AROUND AT LEAST THROUGH
MIDDAY BEFORE CLEARING FROM WEST TO EAST AS HIGH PRESSURE BUILDS
EASTWARD FROM THE MID MISSISSIPPI VALLEY.
THE CHALLENGE FOR TODAY IS HIGH TEMPS. HIGH WERE ACTUALLY AT
MIDNIGHT AND TEMPERATURES WILL NOW BEGIN FALLING BEHIND THE FRONT AS
COLDER AIR FILTERS INTO THE OHIO VALLEY. EXPECT THAT DURING AT LEAST
THROUGH THE MORNING HOURS TEMPERATURES WILL FLUCTUATE TOO MUCH AND
WILL REMAIN IN THE UPPER 30S TO LOW 40S BEFORE FALLING OFF IN THE
AFTERNOON AND THROUGH TUESDAY NIGHT. THEREFORE...EXPECT TEMPERATURES
TO START IN THE UPPER 30S NORTHWEST TO THE LOW OR MID 40S SOUTHEAST
AND FALL INTO THE LOW 30S NORTHWEST TO THE UPPER 30S SOUTHEAST BY 6
PM.
VERY DRY AIR WILL FIND ITS WAY INTO THE OHIO VALLEY TONIGHT WITH
DEWPOINTS FALLING INTO THE UPPER TEENS TO LOW 20S AND OVERNIGHT LOW
TEMPERATURES WILL FALL TO NEAR OVERNIGHT LOW DEWPOINTS. EXPECT LOWS
FROM THE UPPER TEENS TO MID 20S.
.LONG TERM (WEDNESDAY - MONDAY)...
WEDNESDAY-THURSDAY...
HIGH PRESSURE WILL BE IN PLACE MIDWEEK SO THE WEATHER WILL BE DRY
THIS PERIOD. WEDNESDAY...OUR AREA IS ON THE BACKSIDE OF THE TUES
MORN FRONT...SO WITH MAINLY NORTHERLY WINDS DESPITE CLEAR SKIES...WE
SHOULD REACH HIGHS IN THE UPPER 30S TO LOWER 40S. THE SFC HIGH WILL
SLIDE TO THE EAST BY THURSDAY AND WITH WARM AIR ADVECTION...SUNNY
SKIES AND A WESTERLY FLOW ALOFT IN PLACE...OUR CWA WILL SEE HIGHS IN
THE LOW/MID 40S N TO THE LOW 50S ACROSS THE SOUTH UP AGAINST TN.
THIS IS A TREND TOWARD THE WARMER MET MOS. OVERNIGHT LOWS WILL BE IN
THE 20S...BEING SLIGHTLY WARMER THRS NIGHT.
FRIDAY-SATURDAY...
BETTER MODEL AGREEMENT FOR THIS PERIOD BETWEEN THE GFS AND EURO...SO
HAVE HIGHER CONFIDENCE IN COLDER TEMPS AND A BETTER CHC FOR SNOW
MAINLY ON SATURDAY.
BY FRIDAY A CLIPPER DIVES OUT OF CANADA ALMOST DUE SOUTH ACROSS THE
CENTRAL PLAINS. IT WILL REACH OUR REGION BY LATE FRIDAY
NIGHT...BARELY BRINGING ANY MOISTURE WITH IT. KEPT THE SLIGHT CHC
POPS FRIDAY NIGHT...BUT MADE IT ALL LIGHT SNOW SINCE ANY MOISTURE
WILL NOT REACH OUR AREA UNTIL AFTER MIDNIGHT FRIDAY NIGHT...WHERE
TEMPS WILL BE IN THE UPPER 20S TO AROUND 30 AT THAT TIME.
THIS TROUGH WILL NOT MOVE TOO QUICKLY SINCE LOW PRESSURE OVER THE
SERN CONUS WILL KEEP IT IN PLACE OVER THE LOWER OH VALLEY. SO NOT
ONLY WILL IT TRAVERSE SLOWLY TO THE EAST...IT WILL ALSO BRING IN
EVEN COLDER AIR FROM THE NEW ENGLAND AREA...MOST LIKELY KEEPING OUR
SATURDAY HIGHS IN THE MID 30S/MAYBE UPPER 30S SOUTH). LIGHT SNOW
WILL LIKELY OCCUR BUT NOT EXPECTING ANYTHING MORE THAN LIGHT ACCUMS
SINCE DEEP MOISTURE IS LACKING. BY LATE SATURDAY NIGHT...THE UPPER
TROUGH WILL BE OVER OUR FAR ERN CWA...WITH SCATTERED LIGHT SNOW AND
FLURRIES CONTINUING. SATURDAY NIGHT LOWS WILL DROP INTO THE LOW
20S...BUT GIVEN THE VERY COLD TEMPS AT 850MB...IT COULD BE MUCH
COLDER IF SKIES WERE GOING TO BE CLEAR.
PREVIOUS DISCUSSION FOR SUNDAY-MONDAY...
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 (12Z TAF ISSUANCE)...
LOW CLOUDS BEHIND A COLD FRONT THAT PASSED THROUGH THE REGION
OVERNIGHT WILL PERSIST THROUGH MUCH OF THE MORNING BEFORE STARTING
TO CLEAR FROM THE NORTHWEST TO THE SOUTHEAST IN THE AFTERNOON. MVFR
CIGS CURRENTLY AT SDF AND BWG WILL WORK INTO LEX EVENTUALLY. BY
AROUND 21Z CIGS SHOULD START TO CLEAR OUT OF SDF AND BWG AND BY 00Z
AT LEX. THE OVERNIGHT HOURS WILL BE CLEAR AS MUCH DRIER AIR WORKS
INTO THE REGION. NORTHWEST WINDS TODAY UP TO 12 KTS WILL BE
NORTHEASTERLY OVERNIGHT UP TO 6 KTS.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM........LMS
LONG TERM.........AL
AVIATION..........LMS
