FXUS63 KLMK 242331
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
631 PM EST THU DEC 24 2009
...UPDATE TO AVIATION...
.AVIATION....(00Z TAF ISSUANCE)
WOW! I HAD TO SHARPEN MY PENCIL TWICE TO GET ALL OF THE ISOBARS
ON MY SURFACE ANALYSIS! NOT SURE I CAN RECALL EVER SEEING A
SURFACE LOW AS TIGHTLY WOUND UP AS THE ONE CENTERED OVER NORTHWEST
ARKANSAS AT 22Z. WHILE THE GRADIENT OVER CENTRAL KY IS NOT AS
TIGHT AS OUT TO THE WEST...IT WILL NOT STAY THIS WAY. BWG GUSTS
HAVE JUMPED UP THE PAST HOUR...WITH A PEAK WIND OF 35KTS AT 2249Z.
AMDAR SOUNDINGS FROM SDF THE PAST HOUR SHOW 60KT WINDS AT 050
AGL...BUT ONLY 33KT AT 020 AGL. HOWEVER...UPSTREAM CLOSER TO THE
SFC LOW...MEM AMDAR SOUNDINGS SHOWED 55KTS NEAR 020 AGL. AS THE
LOW TRACKS NE...THIS AREA OF HIGHER WINDS WILL SWING CYCLONICALLY
THOUGH OUR FCAST AREA.
WITH ALL OF THE ABOVE SAID...WHILE PRECIPITATION IS STILL PROGGED TO
MOVE THROUGH...THE PRIMARY PROBLEM FOR THIS TAF ISSUANCE WILL BE
BOTH SFC WINDS AND LLWS AS THE LOW LEVEL JET INTENSIFIES. BUFKIT
ETA FCST SOUNDINGS SHOW UP TO 90KTS AT 060 BY 09Z OVER SDF. WHILE
NMM AND GFS ARE NOT AS STRONG...THE TREND IS THE SAME FOR
OVERNIGHT. THE LOW LEVEL JET STARTS TO WEAKEN QUICKLY AFTER
12Z...LESSENING THE LLWS THREAT. EVEN SO...SURFACE WINDS WILL
CONTINUE TO GUST OVER 30KTS THROUGH THE DAY.
BOTTOM LINE...CONTINUE TREND OF 18Z TAFS.
&&
.PREV DISCUSSION... /ISSUED 306 PM EST THU DEC 24 2009/
SHORT TERM (TODAY AND TONIGHT)...
PROVIDED SANTA DECIDES TO DROP DOWN FROM NORTHERN PLAINS INTO TEXAS
AND THEN COMES UP ACROSS THE TENNESSEE VALLY 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 (FRIDAY - 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.
&&
.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..........JBS
