FXUS63 KJKL 080219
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
919 PM EST MON DEC 7 2009

.SHORT TERM.../THE REST OF TONIGHT/...UPDATED

EASTERN KENTUCKY REMAINS UNDER A CANOPY OF LOW STRATOCU. WAA IS
TAKING PLACE AT 850 MB SO THIS CLOUD DECK WILL BE TRAPPED UNDER THE
INVERSION THE REST OF TONIGHT. LATEST SOUNDING FROM OHX REVEALS VERY
DRY AIR BETWEEN 500 AND 850 MB. THINK THIS WILL BE TOO MUCH TO
OVERCOME FOR ANY PRECIPITATION...SO WILL REMOVE POPS FROM THE
SOUTHWEST FOR TONIGHT AND HOLD EVERYTHING OFF UNTIL TOMORROW.
TEMPERATURES ARE RUNNING A BIT MILDER THAN FORECAST AS WELL...SO WILL
BUMP THESE UP A BIT...MAINLY SOUTH OF THE MOUNTAIN PARKWAY.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TONIGHT THROUGH WEDNESDAY NIGHT/

FOCUS IS NOW QUICKLY SHIFTING TO OUR MIDWEEK SYSTEM WHICH IS POISED
TO BRING A PERIOD OF HEAVY RAINFALL AND PERHAPS SOME STRONG GUSTY
THUNDERSTORMS... ALONG WITH A POTENTIALLY DAMAGING WIND EVENT FROM
LATE TUESDAY NIGHT INTO WEDNESDAY EVENING.

FOR TONIGHT... CLOUD COVER WILL BE EXTENSIVE THROUGH THE NIGHT WHICH
SHOULD KEEP OUR TEMPS ABOVE GUIDANCE. ISENTROPIC LIFT GENERATED
PRECIP MAY SNEAK INTO OUR SOUTHERN COUNTIES BEFORE DAWN SO WILL
INTRODUCE SLIGHT CHANCE POPS FOR LOCATIONS SOUTH OF THE HAL ROGERS
PARKWAY LATE TONIGHT. AGAIN... CLOUD COVER SHOULD KEEP TEMPS TOO
WARM FOR ANYTHING BUT LIQUID PRECIP.

RAIN WILL THEN OVERSPREAD THE AREA QUICKLY FROM SOUTHWEST TO
NORTHEAST ON TUESDAY. EXCELLENT UPPER DIFFLUENT FLOW AND SURGING LOW
LEVEL JET PRODUCE IMPRESSIVE FORCING IN THE AFTERNOON AND THIS WILL
OVERCOME LOW LEVEL DOWNSLOPE FLOW TO GENERATE MEASURABLE RAINS
EVERYWHERE BY LATE AFTERNOON SO INCREASED POPS TO 100 PERCENT AREA
WIDE. PWATS QUICKLY INCREASE TO BETWEEN 1.00 AND 1.25 INCHES BY
AFTERNOON SO LOCALLY HEAVY RAINFALL APPEARS LIKELY INTO THE EVENING
HOURS. UPPED QPF INTO THE 1 TO 1 1/2 INCH RANGE AREA WIDE
TUESDAY/TUESDAY NIGHT. THE QUICK MOVEMENT OF THE SYSTEM SHOULD KEEP
AMOUNTS IN CHECK AND LIMIT ANY HYDRO CONCERNS. ONLY A FEW SHOWERS
SHOULD LINGER BEHIND THE FRONT ON WEDNESDAY WITH ANY PRECIP SHIFTING
OVER TO SNOW AS COLDER AIR POURS IN LATE IN THE DAY INTO WEDNESDAY
NIGHT... BUT NO ACCUMULATIONS ARE ANTICIPATED.

NOW ONTO THE WIND THREAT... GFS/ECMWF BOTH INDICATE A VERY STRONG
LOW LEVEL JET COINCIDENT WITH THE FRONT AND LAGGING BEHIND THE FRONT
THROUGH THE DAY WEDNESDAY. THERE REMAINS THE POSSIBILITY OF A LINE
OF LOW TOPPED THUNDERSTORMS... OR PERHAPS JUST SHOWERS...
ACCOMPANYING THE FRONT AS IT RACES ACROSS THE AREA JUST PRIOR TO
DAWN ON WEDNESDAY. THESE SHOWERS/STORMS WILL HAVE THE POTENTIAL TO
MIX DOWN DAMAGING WINDS FROM ABOVE. BEHIND THE FRONT... BUFKIT
SOUNDINGS INDICATE WIND SPEEDS AT THE TOP OF THE MIXED LAYER UP TO
55 KTS. ALSO... GFS MOS WIND SPEED GUIDANCE IS AS HIGH AS I HAVE
SEEN IT WITH A 26 KT SUSTAINED SPEED OFFERED AT 18Z WEDNESDAY AT
LOZ. NEEDLESS TO SAY IT WILL BE VERY WINDY... AND FEEL THE THREAT IS
SUFFICIENTLY HIGH THAT WE WILL HAVE GUSTS UP TO AND OVER 50 KTS AT
THE SURFACE THAT A HIGH WIND WATCH WILL BE ISSUED FOR THE ENTIRE
AREA FOR LATE TUESDAY NIGHT INTO WEDNESDAY EVENING. THE WINDS SHOULD
REMAIN GUSTY THROUGH WEDNESDAY NIGHT BUT SUBSIDE ENOUGH THAT
DAMAGING WINDS SHOULD NO LONGER BE A THREAT FROM LATE EVENING ON.

.LONG TERM.../THURSDAY THROUGH MONDAY/

EXTENDED MODELS ARE IN RARE AGREEMENT UNTIL THE TAIL END OF THE
ECMWF. FOR THAT PORTION THAT MATCHES THE GFS...THE GFS IS ONLY
SLIGHTLY FASTER TOWARD DAY 6-7. FCST STARTS OUT DRY UNTIL EARLY SAT
WHEN THE DOMINATE HIGH PRESSURE SLIPS TO THE DELMARVA REGION AND
ALLOWS RETURN FLOW FROM THE GULF. THE 50H FCST IS SHOWING NEARLY
ZONAL FLOW WITH THE MAJOR CYCLONE TRACKING THRU SRN CONTINENTAL
CANADA. WEAK 50H WAVE IN THE SRN STREAM WILL PUSH ACROSS THE PLAINS
AND PROVIDE THE IMPETUS FOR PCPN THIS WEEKEND. COULD BE A MIXED BAG
OF PCPN TYPES WITH SNOW AT NIGHT...RAIN SAT AFTERNOON AND A MIX IN
BETWEEN. TOTAL SNOW ACCUMULATION FOR THE TWO DAY EVENT LOOKS TO BE
LESS THAN AN INCH FOR MOST AND WITH THE RAIN IN THE MIDDLE...NOT
EXPECTING ANY SIGNIFICANT ACCUMULATION. MAIN CONCERN AS WE GET A
LITTLE CLOSER TO THE EVENT...WITH THE EARLY SNOW...MELTED BY THE
RAIN...REFREEZE WITH THE NEXT ROUND OF SNOW AND PROVIDE A VERY
HAZARDOUS SITUATION.

&&

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

ANTICIPATING MVFR CIGS AROUND 2K AT ALL THREE TAF SITES THROUGH THE
5-7Z TIME FRAME TONIGHT. SLOWED DOWN THE BREAKING UP OF THE LOWER
CLOUD LAYER TONIGHT AS THE LATEST SURFACE OBS HAVE A MOSTLY OVERCAST
LAYER OF 1.5-2.5K CLOUD LAYER ENTRENCHED ACROSS A LARGE PORTION OF
THE TENNESSEE AND OHIO VALLEYS. ONCE THESE CLOUDS BREAK UP A BIT
AFTER 5Z TONIGHT...THE LAYER OF CLOUDS ABOVE...CIGS AROUND 6K...WILL
BECOME THE DOMINATE LAYER THROUGH 16Z OR SO AT LOZ AND SME...AND 20Z
AT JKL. MVFR CIGS WILL PREVAIL ONCE AGAIN AT THE TAF SITES AROUND
18Z...AS THE FIRST AREA OF PRECIPITATION MOVES IN FROM THE SOUTHWEST.
SME AND LOZ WILL BE IMPACTED FIRST AS LIGHT RAIN SHOWERS MOVE THROUGH
AROUND 16Z TOMORROW. THE RAINFALL WILL QUICKLY OVERS READ THE AREA AND
WILL BECOME MODERATE TO HEAVY AT TIMES BY 20 OR 21Z TUESDAY. JKL WILL
SEE THE FIRST DROPS OF RAIN BETWEEN 19 AND 20...WITH THE MOST
WIDESPREAD AND INTENSE RAIN OCCURRING AFTER 20Z. CIGS WILL DECREASE
QUICKLY THROUGHOUT THE AFTERNOON TOMORROW...GETTING DOWN AROUND 1.5K
BY THE END OF TAF VALID PERIOD. 

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY 
EVENING FOR KYZ044-050>052-058>060-068-069-079-080-083>088-104-
106>120.

&&

$$

SHORT TERM...ABE/GEOGERIAN
LONG TERM....DUSTY
AVIATION...AR