FXUS63 KJKL 262344
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
644 PM EST THU NOV 26 2009

.SHORT TERM.../TONIGHT THROUGH SATURDAY NIGHT/

A TROUGH WILL PASS EAST OVER THE REGION TONIGHT. THE LOWER/MID LEVEL
PORTION OF THE TROUGH WILL BE PRECEDED BY WARM AIR ADVECTION IN THE
850-700 MB LAYER...WITH THE ASSOCIATED ISENTROPIC LIFT BRINGING
CLOUDS AND A POTENTIAL FOR PRECIP. PRECIP TYPE WILL BE A FUNCTION OF
TEMPS IN THE LOWEST LEVELS...WITH AIR ALOFT COLD ENOUGH TO SUPPORT
FORMATION AS SNOW. WITH THE WARMEST AIR AT THE SURFACE AND THE FREEZING
LEVEL EXPECTED AROUND 2K FEET IN THE PRECIP AREA...WILL EXPECT SNOW
TO MIX IN AT SURFACE TEMPS WELL ABOVE FREEZING...PROBABLY AROUND 36.
ABOVE 2K FEET WHERE SURFACE TEMPS WILL DIP BELOW FREEZING...SOME
LIGHT ACCUMULATION OF UP TO AN INCH MAY OCCUR.

DEEP MOISTURE WILL BE MOVING OUT BY 12Z...WITH DRY AIR AT LEVELS
COLDER THAN -10C BY THAT TIME...SO WILL NOT INCLUDE PRECIP ON
FRIDAY. WITH RIDGING AT THE SURFACE AND ALOFT BUILDING IN FROM THE
WEST ON FRIDAY...SKIES WILL BECOME MOSTLY SUNNY DURING THE DAY.
CLEAR OR MOSTLY CLEAR SKIES THEN LAST THROUGH SATURDAY NIGHT. AS THE
SURFACE RIDGE SLIPS TO OUR EAST ON FRIDAY NIGHT...WARM AIR ADVECTION
WILL RETURN THROUGH THE REMAINDER OF THE PERIOD. THIS WILL LEAD TO
RIDGE/VALLEY LOW TEMP DIFFERENCES BOTH FRIDAY NIGHT AND SATURDAY
NIGHT. 

.LONG TERM.../SUNDAY THROUGH THURSDAY/

SPLIT STEAM FLOW BETWEEN POLAR AND SUBTROPICAL JET WILL MAKE THE 
EVOLUTION OF THE EXTENDED UNPREDICTABLE...ALTHOUGH IT CAN BE SAID 
WITH CONFIDENCE THAT THE PERIOD WILL BE QUITE ACTIVE. CONFIDENCE 
REMAINS FAIRLY HIGH IN THE FIRST OF WEATHER MAKING SYSTEM IMPACTING 
THE AREA MAINLY ON MONDAY. HAVE CONTINUED LIKELY POPS FOR THE MONDAY 
AFTERNOON TIME PERIOD...WITH GRADUALLY INCREASING/DECREASING POPS ON 
EITHER SIDE. THIS EVENT...IN THE FORM OF ALL RAIN...WILL BE THANKS 
TO A STRONG COLD FRONT PUSHING THROUGH THE AREA ON MONDAY NIGHT. MID 
LEVEL SUPPORT WILL EXIST IN THE FORM OF POSITIVE TILT TROUGH AND THE 
UPPER LEVELS SUPPORTED BY A 140 KNOT H3 JET. WILL LINGER POPS IN A 
BIT LONGER ON TUESDAY TO ACCOUNT FOR BRIEF PERIOD OF UPSLOPE FLOW...
HOWEVER MOISTURE SHOULD BE FAIRLY SHALLOW AND FLOW BECOMES 
UNFAVORABLE BY LATE TUESDAY MORNING.

BRIEF RIDGING LOOKS TO BUILD INTO THE AREA TUESDAY AND TUESDAY NIGHT 
BEFORE THE APPROACH OF A MID LEVEL WAVE AROUND THE GULF OF MEXICO 
DRIVEN BY AN ACTIVE SUBTROPICAL JET. AT THIS POINT...MODELS ARE 
DEVELOPING A SURFACE LOW THAT TRACKS SOUTH OF THE CWA WITH PLENTY OF 
MOISTURE TO WORK WITH. LOW LEVELS LOOK TO BE TOO WARM FOR MUCH IN 
THE WAY OF FROZEN PRECIPITATION AT THIS POINT...HOWEVER WILL HAVE TO 
KEEP AN EYE ON HOW THIS SYSTEM EVOLVES. HAVE GRADUALLY INCREASING 
POPS FROM SOUTH TO NORTH ON WEDNESDAY AND WEDNESDAY NIGHT...HOWEVER 
WILL TAPER POPS IN THE EASTERN CWA AS STRONG SOUTHEASTERLY FLOW IN 
THE LOW LEVELS OVER THE TERRAIN WILL CREATE DOWNSLOPING/DRYING AND 
WILL TAKE LONGER TO SATURATE COLUMN. WILL GO WITH CHANCE POPS FOR 
NOW UNTIL DETAILS BECOME A BIT MORE AGREEABLE AMONGST MODELS.

KEPT WITH THE TREND WELL BELOW GUIDANCE ON SUNDAY AFTERNOON AS CLOUD 
COVER DAMPENS MIXING HEIGHTS AND STAYED WELL BELOW GUIDANCE. SUNDAY 
NIGHT AND MONDAY SHOULD BE A LOW DIURNAL RANGE AS RAIN KEEPS LOW 
TEMPS UP AT NIGHT AND CLOUDY SKIES KEEP HIGH TEMPS DOWN. SKIES BEGIN 
TO CLEAR ON MONDAY NIGHT AND TUESDAY AND PARTLY CLOUDY SKIES SHOULD 
ALLOW FOR SOME TEMPERATURE RECOVERY DESPITE COLD FRONTAL PASSAGE. 
HIGHS IN THE MID TO UPPER 40S LOOK REASONABLE. TUESDAY NIGHT COULD 
FAVOR A SMALL RIDGE/VALLEY SPLIT UNDER PARTLY CLOUDY SKIES AND 
RETURN FLOW AT THE RIDGETOP LEVEL. SECOND SYSTEM APPROACHES FROM THE 
SOUTH WITH SMALL DIURNAL RANGES ONCE AGAIN ON WEDNESDAY...WEDNESDAY 
NIGHT...AND THURSDAY.
&&

.AVIATION.../00Z TO 24Z/...UPDATED

COLDER AIR IS MOVING INTO EASTERN KENTUCKY AHEAD OF A SURFACE TROUGH
AND UPPER TROUGH WHICH WILL BE MOVING ACROSS THE AREA TONIGHT.
LOOKING UPSTREAM...EXPECT MOSTLY MVFR CIGS WITH THIS
SYSTEM...HOWEVER...THERE MAY BE SOME IFR CIGS NEAR THE 1500 FT LEVEL
WITH THE HEAVIER SHOWERS. THESE SHOWERS WILL BE A MIX OR RAIN AND
SNOW...WITH ALL SNOW AT HIGHER ELEVATIONS. AS USUAL THE CLOUDS SHOULD
HANG IN THERE LONGER THAN THE NUMERICAL GUIDANCE INDICATES. EXPECT A
RETURN TO VFR AFTER 19Z AS THE UPPER TROUGH MOVES OFF TO THE EAST.

&&

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

&&

$$

SHORT TERM...HAL
LONG TERM....SCHOETTMER
AVIATION...JJ