000
FXUS63 KLMK 061345 CCA
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
900 AM EST TUE JAN 6 2009
.MORNING UPDATE...
WILL ALLOW THE WINTER WEATHER ADVISORY TO EXPIRE AT 9 AM THIS
MORNING. TEMPERATURES HAVE RISEN TO AT LEAST 32 EVERYWHERE EXCEPT
PERHAPS THE NORTHERN SECTIONS OF THE 5 COUNTIES STRETCHING FROM
DUBOIS THROUGH JEFFERSON COUNTY INDIANA. EARLIER CALLS TO LOCAL
EMERGENCY MANAGERS INDICATE VERY MINOR ICING...IF ANY...AND ONLY
MINOR INCONVENIENCES TO TRAVELERS.
WITHIN THIS FLAT SOUTHWESTERLY FLOW...ENERGY WILL BE MOVING ACROSS
THE REGION IN SEVERAL PIECES. AN INITIAL AREA OF LIGHT RAIN HAS
EXITED INTO OHIO. EXPECT DINGY...DRIZZLY WEATHER TO CONTINUE THE
REST OF TODAY WITH OCCASIONAL LIGHT RAIN.
A SECOND AREA OF RAIN NOW MOVING INTO WESTERN TENNESSEE WILL AFFECT
SOUTHEASTERN KENTUCKY LATER THIS AFTERNOON AND EVENING.
&&
.SHORT TERM (TDA AND TONIGHT)...
WILL MOVE THE ADVISORY 1 TIER OF COUNTIES FARTHER TO THE NORTH AND
END IT SOONER...BY 9 AM EST. COORDINATED WITH PAH AND ILN.
LIGHT FRZG RAIN...MIXED AT TIMES WITH SLEET...HAS BEEN CONFINED TO
OUR SRN INDIANA COUNTIES AND PARTS OF OLDHAM...HENRY AND TRIMBLE
COUNTIES IN KY. THIS SHUD NOT CHG MUCH THRU SUNRISE...WITH TEMPS
STEADY OR RISING A DEG OR SO. THE MOST PRONE AREAS
(BRIDGES-OVERPASSES) FOR THOSE COUNTIES JUST SOUTH OF THE
NEW ADVISORY AREA...MAY DEVELOP SOME BRIEF ICING (ITS 31 DEG AT
NWS-LMK)...BUT THE TEMP AT THE PRESENT IS TRENDING UP...AS WELL AS
THOSE ACRS THE REGION WITH SENSIBLE HEAT FLUX IN PROGRESS DUE TO
PRECIP FALLING FROM A WARMER LAYER JUST ABOVE THE SFC.
LEAD SHRTWV TROF/VORT MAXS IN SRN STREAM FCST TO PHASE WITH NRN
STREAM IMPULSES AND APPROACH OUR FA TDA WHILE LNWV TROF AXIS MOVES
INTO THE PLAINS. STRONGER SHRTWV TROF PROGGED ACRS E TEXAS AT 00Z
TNGT...THEN FCST TO APPROACH AND MOVE INTO OUR FA BY 12Z WED.
QUASISTNRY SFC BNDRY HAS BEGUN A SLIGHT NWD DRIFT INTO THE TN VLY
WITH WAVE DEVELOPMENT NOTED ON THE BNDRY ACRS NRN MS INTO SRN
MIDDLE TN. THIS PROCESS WILL CONTINUE TDA WITH NAM/GFS INDICATING A
DEEPENING TROF AXIS FROM NRN AL INTO EKY. WITH THE APPROACH OF
SHRTWV ENERGY AND DEEPENING TROF...ASCENT AND LOW LEVEL WARM MOIST
ADVECTION WILL INCREASE TDA AND RAIN SHUD BECOME WIDESPREAD.
CONTINUED DEEPENING TROF OF LOW PRES PROGGED TO BE ACRS EKY/THE
VIRGINIAS TNGT WITH BACKLASH PCPN-RAIN CHANGING TO OR MIXING WITH
SNOW FROM NW TO SE EXPECTED TOWARD SUNRISE WED.
.LONG TERM (WEDNESDAY THROUGH MONDAY)...
SUBTLE BUT SIGNIFICANT DIFFERENCES IN MODELS THROUGHOUT THIS
PERIOD...ESPECIALLY WITH RESPECT TO RH FIELDS AND RESULTANT
POPS...AND ESPECIALLY OVER THE WEEKEND. GFS HAS BEEN ODD MAN OUT
WITH DIGGING A 50H CUTOFF LOW DURING THE WEEKEND OVER THE SOUTHERN
ROCKIES AND KEEPING IT THERE FOR REMAINDER OF THE FCST TIME FRAME
WHILE OTHER MODELS BRING A SHARP BUT OPEN WAVE EAST INTO THE CENTRAL
U.S. BY MONDAY MORNING. HAVE OPTED TO GO WITH THE MAJORITY SOLUTION
ON THIS AND HAVE USED ECMWF AS MODEL OF PREFERENCE FOR THIS FCST
PERIOD.
WITH THE ABOVE IN MIND...PRECIP LINGERING WEDNESDAY SHOULD END FROM
WEST TO EAST ACROSS THE AREA AS BULK OF MOISTURE RACES EASTWARD WITH
COLD FRONT. TRAILING STREAM OF HIGHER RH BACK TO NORTHERN PLAINS
WILL BE ENOUGH TO KEEP SOME CLOUDS AROUND...BUT BEST DYNAMICS WILL
BE EAST OF THE AREA WHEN IT COMES IN. AS COLDER AIR MOVES IN...RAIN
SNOW MIX WILL CHANGE OVER TO ALL SNOW BUT WITH LITTLE ACCUMULATION.
POPS DROP FROM WED NIGHT THROUGH FRIDAY...THEN RETURN FRIDAY NIGHT
AND SATURDAY WITH NEXT FROPA...THOUGH CONFIDENCE NOT GREAT ON TIMING
ATTM DUE TO MODEL DISAGREEMENTS. SUNDAY AND MONDAY SHOULD REMAIN DRY.
NO MAJOR TEMPERATURE SWINGS THROUGH THE PERIOD AS PROGRESSIVE
PATTERN NOT ALLOWING MUCH TIME FOR ANY BIG WARM UPS OR COOL DOWNS.
MAX TEMPS MAINLY IN THE 40S WITH MINS MAINLY IN THE 20S TO LOWER 30S.
&&
.AVIATION (12Z TAFS)...
VLIFR TO IFR CONDITIONS EXPECTED TO CONTINUE THRU MUCH OF THE PERIOD
MAINLY DUE TO LIFR CIGS.
LOW PRES WILL DEEPEN IN TN TDA AND CONTINUE TO DO SO TNGT AS IT
MOVES NEWD INTO OH. RAIN WILL BE WIDESPREAD TDA WITH A LULL IN THE
ACTIVITY TNGT. PRECIP WILL DEVELOP ON THE BACKSIDE OF THE LOW LATE
IN THE PERIOD WITH A RAIN/SNOW MIX EXPECTED AT SDF NEAR SUNRISE
WED.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
WEATHER.GOV/LOUISVILLE
SHORT TERM...KIRKPATRICK/JSD
LONG TERM....JBS
AVIATION.....JSD
