FXUS63 KJKL 010758
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
258 AM EST TUE DEC 1 2009

.SHORT TERM.../TODAY THROUGH THURSDAY/...UPDATED

EXPECT SOME FREEZING FOG AND SOME POSSIBLE BLACK ICE THIS MORNING.
HAVE ISSUED AN SPS TO HIGHLIGHT THIS HAZARD. THE TRACK OF THE
SURFACE LOW PRESSURE SYSTEM CONTINUES TO VARY FROM RUN TO RUN.
DECIDED TO GO WITH THE ECMWF...NAM...AND SREF THAT KEEPS THE TRACK OF
THE LOW ACROSS CENTRAL KENTUCKY. THE GFS IS A OUTLIER AS IT BRINGS
THE LOW DIRECTLY ACROSS EASTERN KENTUCKY. BASED ON THE LATEST MODEL
RUNS...DECIDED TO DELAY THE ONSET OF PRECIPITATION UNTIL WEDNESDAY
MORNING. ALSO RAISED THE POPS ON WEDNESDAY IN LINE WITH ALL THE
MODELS AND MOS GUIDANCE. THE DOWNSLOPING WILL GREATLY REDUCE THE
AMOUNT OF PRECIPITATION...HOWEVER THE FORCING WILL BE TOO GREAT AND
EVEN IN THE TYPICAL DOWNSLOPING AREAS WILL GET MEASURABLE RAINFALL.
BACKED OFF OF THE SNOW ON THE BACK SIDE OF THE FRONT DUE TO LACK OF
ICE CRYSTAL FORMATION. IT IS MORE LIKELY TO SEE SOME DRIZZLE BEHIND
THE FRONT.

.LONG TERM.../THURSDAY NIGHT THROUGH MONDAY/

AMPLIFIED UPPER LEVEL SYSTEM ACROSS THE GREAT LAKES AND SOUTHERN 
CANADA WILL BRING MAINLY A CHILL DOWN ACROSS THE AREA FOR THE END OF 
THE WEEK. THE MODELS HAVE TRENDED SLIGHTLY WARMER WITH THE INITIAL 
SHOT OF COLDER AIR ARRIVING THURSDAY NIGHT. THIS PUTS ICE CRYSTAL 
FORMATION IN JEOPARDY WITH A SHALLOW MOISTURE LAYER GETTING ONLY AS 
COOL AS -6 TO -7C. AS SUCH...WILL MENTION SOME PATCHY DRIZZLE FOR 
THURSDAY NIGHT. DEPENDING ON HOW COOL THE SURFACES GET IN THE HIGHER 
SOUTHEAST TERRAIN...THERE MAY BE A SMALL WINDOW OF FREEZING DRIZZLE 
POTENTIAL BEFORE THE MOISTURE BECOMES TOO SHALLOW. 

HIGH PRESSURE WILL BUILD IN AT THE SURFACE FOR FRIDAY...WITH DRY BUT 
COLD WEATHER EXPECTED. THE LEFTOVER TROUGH AXIS FROM THE GREAT 
LAKES/SOUTHERN CANADIAN SYSTEM WILL THEN MOVE THROUGH ON SATURDAY. 
THE LAST COUPLE OF RUNS OF THE ECMWF HAVE HAD MUCH MORE MOISTURE 
ASSOCIATED WITH THIS TROUGH COMPARED TO THE GFS. WILL MAINTAIN THE 20 
POPS FOR THIS FEATURE...AND IT STILL LOOKS LIKE THAT ANYTHING THAT 
DOES FALL WILL BE IN THE FORM OF SNOW WITH A REINFORCEMENT OF COLDER 
AIR. DRY WEATHER AND A SLOW MODIFICATION IN TEMPERATURES IS THEN 
EXPECTED FOR THE REST OF THE PERIOD AS THE FLOW BECOMES MORE ZONAL 
ALOFT. FOR TEMPERATURES...CONTINUED TO STAY BELOW GUIDANCE FOR THE 
HIGHS IN THE COLD AIR REGIME. DID ADJUST SOME OF THE LOWS UP A 
BIT...CLOSER TO GUIDANCE EARLY IN THE EXTENDED...DO TO LINGERING 
CLOUD COVER.

&&

.AVIATION.../06Z TO 06Z/

AN AREA OF BKN STRATOCU WITH BASES ABOUT 4K MSL WILL CONTINUE TO
MOVE EAST AND SHOULD MOVE OUT OF EASTERN KENTUCKY BETWEEN 8 AND 9Z.
SOME PATCHES OF DENSE FOG HAVE ALREADY FORMED. THE FOG WOULD HAVE
BEEN MORE WIDESPREAD IF IT HAD NOT BEEN FOR THE STRATOCU DECK. WITH
THE DECK MOVING OUT...EXPECT THE FOG TO GET MORE DENSE WITH SOME
VLIFR CONDITIONS...MAINLY IN THE TYPICAL RIVER VALLEYS. EXPECT THE
LOZ AND SME TO BE MVFR AND JACKSON TO STAY VFR. THERE MAY BE SOME
TEMPO MVFR AT JKL AS THE FOG LIFTS OUT OF THE VALLEYS...HOWEVER WILL
NOT INCLUDE IT IN THE TAF. AFTER 13Z...IT WILL STAY VFR UNTIL AROUND
14 TO 15Z ON WEDNESDAY AS THE NEXT FRONT MOVES INTO THE AREA.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$
SHORT TERM...JJ
LONG TERM...GEOGERIAN
AVIATION...JJ