FXUS63 KLMK 250451
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
1151 PM EST THU DEC 24 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM (TONIGHT AND CHRISTMAS DAY)...
PROVIDED SANTA DECIDES TO DROP DOWN FROM NORTHERN PLAINS INTO TEXAS
AND THEN COMES UP ACROSS THE TENNESSEE VALLEY AND INTO THE LOWER OHIO
VALLEY HE WILL MAKE QUICK TIME WITH SUCH A STRONG LOW LEVEL FLOW.
THIS IS THANKS TO A DEEPENING LOW PRESSURE SYSTEM WITH A SURFACE LOW
THAT WILL TRACK FROM EASTERN TEXAS THIS AFTERNOON INTO MISSOURI AND
THEN NORTH INTO IOWA BY TOMORROW NIGHT.
THE MAIN ISSUE FOR OUR FORECAST AREA WILL BE WINDS AS THEY INCREASE
TO 50KTS AT 925MB OVERNIGHT. AN INVERSION JUST ABOVE THE SURFACE
SHOULD KEEP THE STRONGEST WINDS OFF THE GROUND BUT SUSTAINED WINDS
TO 25 MPH WITH SOME HIGHER GUSTS WILL BE POSSIBLE. THE WIND FIELDS
WILL RELAX SOME ON CHRISTMAS DAY BUT WITH BETTER MIXING GUSTS TO 45
MPH WILL BE POSSIBLE. SO WITH THIS IN MIND WE WILL ISSUE A WIND
ADVISORY FOR TONIGHT AND CHRISTMAS DAY... THROUGH 21Z.
THE LOW LEVEL SOUTHEAST DRY FLOW WILL GRADUALLY MOISTEN UP AS THE
WINDS BEGIN TO SHIFT TO THE SOUTH AHEAD OF AN APPROACHING COLD
FRONT. THE HEAVIEST RAIN WILL OCCUR FROM THE 06 TO 12Z TIME FRAME
AND QUICKLY SHIFT TO THE NORTHEAST. BECAUSE OF THE SPEED OF THE
PRECIPITATION RAINFALL AMOUNTS WILL GENERALLY REMAIN UNDER 0.75
INCHES WITH THE HEAVIER AMOUNTS NOTED ACROSS SOUTHERN INDIANA.
COLDER AIR WILL QUICKLY FILTER INTO THE AREA ON CHRISTMAS DAY AND WE
MAY SEE A CHANGE OVER TO SOME VERY LIGHT SNOW ACROSS THE NORTHERN
PORTION OF THE FORECAST AREA LATE IN THE DAY. SNOW FLURRIES WILL BE
POSSIBLE ACROSS THE SOUTH.
THE WARMEST TEMPERATURES WILL OCCUR LATE TONIGHT AND EARLY CHRISTMAS
MORNING WITH FALLING TEMPERATURES DURING THE AFTERNOON.
.LONG TERM (CHRISTMAS NIGHT - THURSDAY)...
CHRISTMAS NIGHT-SUNDAY NIGHT...
FOR THIS HOLIDAY WEEKEND...COLD AND GUSTY CONDITIONS WILL BE THE
RULE WITH OFF AND ON CHANCES FOR FLURRIES AND SNOW SHOWERS.
BEGINNING FRIDAY NIGHT/CHRISTMAS NIGHT...THE SFC LOW CAUSING ALL
SORTS OF PROBLEMS ACROSS THE PLAINS AND MIDWEST WILL BE WRAPPED UP
ACROSS IOWA WITH ITS STRONG UPPER LOW OVER MISSOURI. AS THE LOW
SLOWLY WORKS ITS WAY TOWARDS THE GREAT LAKES...OUR PRECIP WILL EXIT
TO THE NORTHEAST FRIDAY NIGHT...SO HAVE A SMALL AREA OF A RASN MIX
ACROSS THE NERN CWA...CHANGING TO FLURRIES ACROSS THE NORTH. THE
FLURRIES WILL CONTINUE ON AND OFF THROUGH SATURDAY NIGHT AS UPPER
LEVEL ENERGY ON THE SOUTH SIDE OF THE UPPER LOW COMES CLOSE TO THE
CWA.
THE BEST CHANCE FOR SNOW SHOWERS WILL COME SUNDAY INTO SUNDAY
NIGHT...ESPECIALLY ACROSS THE NORTH...AS THE UPPER LOW SWINGS ACROSS
THE REGION FINALLY. HAVE CHC POPS BECAUSE OF THIS WITH THE HIGHEST
CHC NORTH. COULD HAVE MINOR ACCUMS...A DUSTING OR HALF INCH
MAYBE...ACROSS THE NORTH BY MONDAY DAWN. LOWS WILL BE IN THE 20S
EACH NIGHT...WITH THE COLDEST NIGHT SUNDAY NIGHT. HIGHS WILL RANGE
IN THE UPPER 30S SATURDAY AND DROP TO THE LOW 30S ON SUNDAY.
MONDAY-THURSDAY...
THE NEXT WORK WEEK SHOULD BE MOSTLY DRY...WITH TEMPS GENERALLY
COLDER THAN NORMAL FOR THIS TIME OF YEAR. MONDAY WILL STILL BE VERY
COLD AS NORTHWESTERLY WINDS BEHIND THE UPPER LOW BLANKET THE REGION.
PLUS ANY SNOW FROM THE NIGHT BEFORE AND CLOUDY SKIES WILL KEEP TEMPS
DOWN. HIGHS WILL BE IN THE LOW 30S N TO THE UPPER 30S S. A SLOW
"WARM-UP" WILL TAKE PLACE THROUGH THURSDAY WITH HIGHS WED AND THURS
IN THE LOW 40S SOUTH AND UPPER 30S NORTH. THE UPPER LEVEL FLOW
BECOMES WSWRLY...WITH A WEAK SYSTEM TRAVERSING THE GULF STATES
WEDNESDAY. THIS WILL BRING CLOUDY SKIES TO OUR SRN CWA. BY
THURSDAY...BROAD TROUGHING WILL AFFECT THE CENTRAL CONUS...WITH A
WEAK UPPER TROUGH PASSING THROUGH THE LOWER GREAT LAKES AND POSSIBLY
THIS FAR SOUTH THURSDAY-THURSDAY NIGHT. THIS COULD GENERATE LIGHT
SNOW SHOWERS FOR OUR AREA...SO HAVE INSERTED THIS INTO THURSDAY
NIGHT'S GRIDS. OTHERWISE...LOOKS TO BE A MOSTLY DRY WEEK.
&&
.AVIATION (06Z TAF ISSUANCE)...
IT/S A ROUGH RIDE FOR SANTA TONIGHT AS TIGHTLY WOUND LOW PRESSURE
MOVING FROM ARKANSAS TO IOWA DURING THIS FORECAST PERIOD BRINGS
STIFF WINDS TO THE REGION. LLWS WILL CONTINUE THROUGH THE PRE-DAWN
HOURS. AT 02Z AN ACARS/AMDAR SOUNDING FROM KBNA SHOWED 43KT
SOUTHEASTERLY WINDS AT 2000 FT. AT 04Z AN AMDAR TRACE AT KSDF
DISPLAYED 40KT AT 2000 FT. ALSO AT 04Z KLVX VWP SHOWED 40KT WINDS
AND KOHX AND KHPX 88D VWPS SHOWED 45KT WINDS AT 2000 FT. THESE
NUMBERS ARE IN APPROXIMATE AGREEMENT WITH MODEL PROGS FROM YESTERDAY
AND THIS EVENING. LLWS SHOULD DIMINISH AFTER SUNRISE.
A BAND OF RAIN WILL PIVOT THROUGH THE TERMINALS DURING THE LATE
NIGHT/EARLY MORNING HOURS. CIGS AND VSBYS WILL LIKELY DROP INTO
HIGH-END MVFR DURING THE RAIN...AND THEN RETURN TO LOW-END VFR AFTER
THE RAIN DEPARTS LATER THIS MORNING. PRIMARILY DRY CONDITIONS ARE
EXPECTED FROM MID MORNING THROUGH THIS AFTERNOON AND EVENING.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ FRIDAY FOR KYZ023>043-
045>049-053>057-061>067-070>078-081-082.
IN...WIND ADVISORY UNTIL 4 PM EST /3 PM CST/ FRIDAY FOR INZ076>079-
083-084-089>092.
&&
$$
SHORT TERM........JA
LONG TERM.........AL
AVIATION..........13
