FXUS63 KJKL 021748
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1248 PM EST WED DEC 2 2009
.SHORT TERM.../THE REST OF TODAY/
FORECAST IS ON TRACK THIS MORNING. MADE SOME MINOR ADJUSTMENTS TO
ISC GRIDS AND FRESHENED UP WORDING IN THE ZONES A BIT. WAS CONCERNED
ABOUT THE POTENTIAL OF SOME THUNDER LATE THIS AFTERNOON. FORECAST
SOUNDINGS DO SHOW SOME SHEAR AT THE LOWEST LEVELS AND SOME VERY WEAK
ELEVATED INSTABILITY AS MID LEVEL LAPSE RATES STEEPEN A BIT THIS
AFTERNOON. HOWEVER...THERE HAS BEEN NARY A HINT OF ANY THUNDER
UPSTREAM AND IN GENERAL...WINDS FIELDS DO NOT LOOK AS IMPRESSIVE AS
EARLIER RUNS. DID MAINTAIN CURRENT WIND LAKE ADVISORY FOR OUR FAR
SOUTHEASTERN ZONE...BUT IT APPEARS MORE LIKELY THAT STRONGEST GUSTS
WILL BE RESTRICTED TO THE HIGHEST ELEVATIONS. CAN NOT RULE OUT AN
OCCASIONAL MIX DOWN OF SOME OF THE HIGHER GUSTS TO THE VALLEY FLOOR
THOUGH...SO WILL LET CURRENT ADVISORY RIDE.
THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...
/TODAY THROUGH FRIDAY NIGHT/
WIDESPREAD RAINS ARE ON THE WAY AS INITIAL OVERRUNNING PRECIPITATION
ENCROACHES FROM THE TENNESSEE VALLEY. TEMPERATURES ARE HOVERING IN
THE MIDDLE 30S IN THE COOLER VALLEYS ALONG AND SOUTH OF THE HAL
ROGERS PARKWAY AND HIGHWAY 80...WITH SHELTERED VALLEYS HOLDING IN THE
LOWER 30S TO THE NORTH. DO NOT EXPECT THERE TO BE ANY FREEZING RAIN
OUT OF THIS AT THE ONSET IN THE NORTH WITH GROUND TEMPERATURES WELL
ABOVE FREEZING AS WELL AS A SIGNIFICANT WARM NOSE IN PLACE AT 850 MB.
ALL MODELS ARE CLUSTERED WELL WITH TRACKING DEEPENING LOW PRESSURE
ACROSS THE TENNESSEE VALLEY AND THROUGH CENTRAL KENTUCKY BY THIS
EVENING. A STRONG LOW LEVEL JET WILL PROVIDE A THREAT FOR GUSTY WINDS
IN THE SOUTHEASTERN TERRAIN...SO WILL LET THE ADVISORY RIDE.
ST READY RAINFALL WILL TAPER OFF EARLY THIS EVENING...WITH THE THREAT
OF VERY LIGHT RAIN OR DRIZZLE LINGERING THROUGH THURSDAY EVENING...AS
COLDER AIR MOVES IN FROM BEHIND THE DEPARTING SYSTEM. ICE CRYSTALS
LOOK EVEN TOUGHER TO COME BY COMPARED TO LAST NIGHT...SO ONLY
MENTIONED DRIZZLE. EXPECT MOISTURE TO BE SHALLOW ENOUGH BY THE TIME
THE HIGHEST SOUTHEAST TERRAIN GOES SUB-FREEZING TO AVOID ANY
GLAZING.
DRY BUT COLD CONDITIONS WILL REIGN ON FRIDAY AS A SURFACE HIGH
PRESSURE RIDGE BUILDS IN. POPS WILL RAMP BACK UP LATE FRIDAY NIGHT AS
FULL LATITUDE TROUGH AXIS MOVES IN FROM THE WEST. MAINTAINED THE 20
TO 30 POPS FOR NOW WITH THIS SYSTEM AT ONSET. ANYTHING THAT FALLS
WILL BE SNOW...HOWEVER LIGHT QPF WILL LIMIT ACCUMULATIONS TO MAINLY
THE HIGHER TERRAIN.
FOR TEMPERATURES...STUCK CLOSE TO PERSISTENCE...WHICH JIVES WELL WITH
THE CURRENT GUIDANCE FOR THE FIRST 24 HOURS...THEN UNDERCUTS GUIDANCE
SIGNIFICANTLY ON THE HIGHS FOR THURSDAY AND FRIDAY...GIVEN THE CLOUDS
AND COLD AIR MASS IN PLACE.
.LONG TERM.../SATURDAY THROUGH TUESDAY/
BETTER THAN USUAL AGREEMENT IN EXTENDED MODEL SOLUTIONS...THROUGH
MONDAY AND THEN THE ECMWF HAS A ZONAL PATTERN...WHEREAS THE GFS
DEVELOPS A TROUGH ACROSS THE WESTERN US. SO CONFIDENCE IS MUCH
BETTER THAN NORMAL THROUGH MONDAY AND THEN SHARPLY DECLINES.
ON SATURDAY...A SHORT WAVE WILL QUICKLY MOVE ACROSS THE AREA. AS IT
DOES...THE MODELS ARE DEVELOPING PRECIPITATION ACROSS THE AREA EVEN
THOUGH THE AREA IS BEING DOMINATED BY HIGH PRESSURE AND THE LOW
LEVEL FLOW IS FROM THE NORTHWEST. THIS SYSTEM WILL BE CLIPPER LIKE
AND THE BEST CHANCE TO GET ANY SNOWFALL TO DEVELOP ARE IN THOSE
AREAS THAT GET HELP FROM UPSLOPE. I AM NOT TOTALLY CONVINCED THE
MOST OF THE AREA WILL GET MEASURABLE PRECIPITATION...BUT IT MIGHT BE
MORE LIKE DRIZZLE AND FLURRIES...DEPENDING ON THE TEMPERATURES.
THINGS THEN REMAIN DRY UNTIL THE NEXT SYSTEM MOVE INTO THE AREA ON
TUESDAY AFTERNOON. THE TIMING OF THIS SYSTEM IS STILL VERY MUCH IN
DOUBT. FOR TEMPERATURES...JUST NUDGED THEM TOWARD CURRENT MODEL
TRENDS AS THE PREVIOUS SHIFT HAD AN EXCELLENT TEMPERATURE FORECAST.
&&
.AVIATION.../18Z TO 18Z/...UPDATED
RATHER LARGE LOW PRESSURE SYSTEM IS RIDING UP THE MID MISSISSIPPI
RIVER VALLEY AND WILL PUSH THROUGH THE OHIO VALLEY OVER THE NEXT 12
TO 24 HOURS. SIGNIFICANT 925MB TO 850 WIND MAX HAS DEVELOPED JUST
OFF THE SFC. HAD A GUSTS TO 33KT AT KPBX WITHIN THE LAST HOUR. IN
ADDITION...KJKL VAD WIND PROFILER IS READING 50 KT FROM THE SE ABOUT
1 KFT TO 1.5 KFT AGL. WITH AN EAST...SE SFC WIND OF 10KTS OR LESS
DECIDED TO INCLUDE SOME LLWS THROUGH THE REMAINDER OF THE AFTERNOON.
OTHERWISE...REGIONAL MOSAIC RADAR TRENDS SUGGEST SHOWERS AND LIGHT
RAIN WILL REDEVELOP DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS. HAD PREDOMINANT MVFR CIGS ADVERTISED BUT CIGS HAVE REMAINED
ANCHORED IN THE VFR RANGE SO FAR. ONLY KSME CIGS HAVE FLIRTED WITH
MVFR AT TIMES. BUT UPSTREAM OBS DO SHOW LOWER CIGS HOWEVER...AND
FCST SOUNDINGS AND TIME SECTIONS WOULD INDICATE THESE LOWER CIGS
WILL ARRIVE EVENTUALLY. THEREFORE GRADUALLY LOWERED CIGS BACK DOWN
LATE THIS AFTERNOON AND THIS EVENING. SFC WINDS WILL VEER TO THE
SOUTH AND INCREASE TONIGHT...THEN GRADUALLY DECREASE AND VEER TO THE
WEST BY THURSDAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR KYZ088-118-
120.
&&
$$
SHORT TERM...GEOGERIAN/RAY
LONG TERM....JJ
AVIATION...RAY
