FXUS63 KJKL 061737
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1237 PM EST SUN DEC 6 2009

.SHORT TERM.../THE REST OF TODAY/

COLD THIS MORNING WITH MOST LOCATIONS REPORTING LOWS IN THE MID
TEENS. THE COLD START TO THE DAY... LINGERING SNOW PACK IN OUR
EASTERN COUNTIES... AND ADVANCING HIGH CLOUDS SHOULD LIMIT OUR
WARMING TODAY WITH MOST LOCATIONS STRUGGLING TO MAKE IT INTO THE
LOWER 40S. INHERITED FORECAST HAS THIS COVERED WELL... BUT WILL
LOWER TEMPS A FEW DEGREES IN THE EAST TO ACCOUNT FOR THE SNOW COVER
THERE A BIT BETTER.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TODAY THROUGH MONDAY NIGHT/...

A FAIRLY QUIET SHORT TERM FORECAST IS IN STORE...CONSIDERING WHAT WE
HAVE BEEN THROUGH AND WHAT IS COMING UP IN THE WEEK AHEAD. HIGH
PRESSURE WILL DOMINATE AT THE SURFACE THROUGH TONIGHT BEFORE
SCOOTING OFF TO THE EAST IN RESPONSE TO AN APPROACHING WEAK SURFACE
LOW OVER THE SOUTHERN GREAT LAKES. MEANWHILE...STRONG ZONAL FLOW
ALOFT WILL HAVE A FEW WEAK WAVES EMBEDDED. THE IMPACT ON SENSIBLE
WEATHER WILL RESULT IN MOSTLY SUNNY SKIES EARLY GIVING WAY TO PARTLY
CLOUDY SKIES LATER TODAY AND CONTINUED INCREASING CLOUDS OVERNIGHT.
MODEL TIME HEIGHTS/SOUNDINGS INDICATE VERY LITTLE CHANCE THAT ANY
SORT OF PRECIPITATION IS GOING TO HIT THE GROUND LATE TONIGHT INTO
MONDAY MORNING AS SATURATION DOES NOT MAKE IT BELOW MID LEVELS WITH
THE PASSAGE OF THIS SYSTEM. FEEL THE MAJORITY OF AREAS WILL SEE
VIRGA...HOWEVER CANNOT COMPLETELY RULE OUT SOME MEASURABLE
PRECIPITATION SO WILL CONTINUE SLIGHT CHANCE POPS. IF PRECIP DOES
FALL AROUND DAWN...WET BULBING WOULD ALLOW FOR MOSTLY LIGHT SNOW.
PRECIPITATION WOULD QUICKLY CHANGE OVER TO RAIN BY MID MORNING AS
TEMPS WARM. AS THE SYSTEM QUICKLY PASSES...WILL MENTION SOME
SPRINKLES LINGERING MONDAY EVENING.

AS FAR AS TEMPERATURES ARE CONCERNED...WENT BELOW THE LOWEST GUIDANCE
FOR TODAY AS A SLOW START COMBINES WITH INCREASING SKY COVER AND LOW
MIXING HEIGHTS. EXPECT TEMPS TO STRUGGLE TO THE LOW 40S...HOWEVER
WOULDNT BE SURPRISED IF THEY DONT MAKE IT OUT OF THE UPPER 30S
DEPENDENT ON SKY COVER. THANKS TO ILN FOR COLLABORATION. FOR
TONIGHT...RIDGES RECOVER UNDER SOUTHWEST FLOW AND VALLEYS SHOULD FALL
TO THE MID 20S...ESPECIALLY IN THE EAST. THIS WILL PROVIDE THE SETUP
FOR A NICE RIDGE/VALLEY SPLIT ON THE ORDER OF 7 TO 10 DEGREES. HIGH
TEMPERATURES STRUGGLE ON MONDAY UNDER HEAVY SKY COVER AND DONT SEE US
GETTING OUT OF THE LOW TO MID 40S. TUESDAY NIGHT SEES TEMPERATURES
RIGHT AROUND THE FREEZING MARK...WITH THE COLDEST VALLEYS IN THE
UPPER 20S.

.LONG TERM.../TUESDAY THROUGH SATURDAY/

MODELS REMAIN RATHER CONSISTENT WITH THE PATTERN THROUGH THE PERIOD 
WITH SOME RIDGING FROM THE GULF OF MEXICO NORTHWEST TOWARD THE GREAT 
LAKES AT THE START OF THE PERIOD WITH AN UPPER LOW OVER THE HUDSON 
BAY REGION AND A TROUGH EXTENDING SOUTHWEST INTO THE NORTHERN 
ROCKIES. THIS TROUGH...HOWEVER...AT THAT POINT IS NOT EXPECTED TO BE
IN PHASE WITH A SHORTWAVE OR SHORTWAVES OVER THE CENTRAL AND SOUTHERN
ROCKIES. THE WSW FLOW ALOFT SHOULD ALSO HAVE ADDITIONAL EMBEDDED
SHORTWAVES. AT THE SFC...AN AREA OF HIGH PRESSURE IS EXPECTED TO BE
OVER THE MIDDLE TO UPPER OH VALLEY REGION...AND EXITING TO THE EAST
AT THE START OF THE PERIOD. ALSO AT THE SFC WILL BE AN AREA OF LOW
PRESSURE OVER THE SOUTHERN ROCKIES/FOUR CORNERS REGION. THE GFS HAS
BEEN CONSISTENT OVER THE LAST COUPLE OF RUNS WITH THE INITIAL DEPTH
AROUND 12Z TUE...THOUGH THE CANADIAN/ NAM/ECMWF AND 12Z/5TH GFS
ENSEMBLE MEAN ARE ABOUT 8 TO 10 MB WEAKER WITH THE PRESS. THE MODELS
ARE IN GOOD AGREEMENT THOUGH WITH A LEAD SHORTWAVE MOVING INTO THE TN
AND OH VALLEY ON TUE AFTERNOON AND THEN THE OVERALL EVOLUTION OF THE
PATTERN WITH THE SOUTHERN ROCKIES TROUGH LIFTING ENE AND THEN TAKING
ON A NEGATIVE TILT BY WED WITH THE LOW REDEVELOPING AND STRENGTHENING
AS IT MOVES FROM THE PLAINS INTO THE MS VALLEY BY 12Z WED AND THEN
INTO THE GREAT LAKES AND ONTARIO WED INTO THU. AT THAT POINT THE
ECMWF MAY BE A STRONG OUTLIER WITH THE SFC PRESS AROUND 12Z WED AND
SOMETHING 5 TO 10 MB WEAKER WITH THE PRESS MAY BE MORE REASONABLE...BUT
STILL POTENT EITHER WAY.

THIS COMBINATION WILL LEAD TO A GRADUALLY STRENGTHENING LLJ TO THE 
50 TO 70KT+ RANGE AND POTENT ISENTROPIC LIFT BY TUE NIGHT. MODELS 
PROJECT THE PW TO CLIMB TO ABOUT 1.1 INCHES ON AVERAGE OR ABOUT 240 
PERCENT OF NORMAL. IN ADDITION...LAPSE RATES AT THE MID LEVEL 
BETWEEN 750 MB AND 650 MB ALSO STEEPEN A BIT AROUND 6Z WED WITH
PLENTY OF DYNAMICS AND SHEAR. THE MODELS ALSO HINT AS SOME POSSIBLE
COUPLING OF A JET STREAK TO OUR NORTH AND ONE MOVING INTO THE TN AND
LOWER OH VALLEY AROUND 6Z ON TUE NIGHT. THIS COMBINATION WILL LEAD TO
A VERY REAL POSSIBILITY OF QPF EXCEEDING ONE INCH SOMEWHERE IN THE
OH/TN VALLEY REGION...POSSIBLY AFFECTING THE NORTHERN CWA...WITH AT
LEAST A HALF OF AN INCH IN THE SOUTH WITH THE QUICK PROGRESSION OF
THE SYSTEM BEING A LIMITING FACTOR.

OPTED TO ADD A SLIGHT CHANCE OF THUNDER AS MENTIONED ABOVE. 
DEPENDING ON THE EVENTUAL WIND DIRECTIONS ALOFT AND STRENGTH OF THE
PRESS GRADIENT SOME GUSTS ON DOWNSLOPING OR MOUNTAIN WAVE ACTION
CANNOT BE COMPLETELY RULED OUT ON TUE NIGHT ALONG THE VA BORDER...BUT
AT THIS POINT IN APPEARS THAT WED WILL BE BREEZY POST FRONTAL. AT
LEAST FOR A TIME AROUND 18Z OR SO ON WED AFTERNOON SUSTAINED WINDS OF
15 TO 25 MPH WITH GUSTS INTO THE ADVISORY RANGE APPEAR POSSIBLE. ALSO 
AT THIS POINT WE WILL CONTINUE TO HIGHLIGHT THIS IN THE HWO. WITH
THE ISENTROPIC LIFT KICKING IN A LITTLE QUICKER ON TUE AFTERNOON
COMPARED TO SOME EARLIER MODEL RUNS AND 21Z SREF POPS INTO THE HIGH
CHANCE TO LIKELY RANGE BY 0Z WED AND INCREASING MOS POPS IN THE WEST
BY LATE TUE AFTERNOON...OPTED TO RAISE POPS IN THE NORTHWEST TWO
THIRDS LATE IN THE DAY ON TUE...WITH AN AREA OF CHANCE POPS IN THE
TYPICAL RAIN SHADOW REGION NEAR THE VA BORDER. OPTED FOR CAT POPS ON
TUE NIGHT WITH SUCH A POTENT SYSTEM MOVING IN AND SOME OF THE REASONS
MENTIONED ABOVE. DEPENDING ON THE TIMING OF THE ONSET OF PRECIP...MAX
T ON TUE MAY BE SUPPRESSED BELOW MOS VALUES...ESPECIALLY THE WARMER
MOS NUMBERS.

IT STILL LOOKS LIKE TEMPS WILL SURGE UPWARD SOMETIME EITHER LATE TUE 
INTO EARLY WED...BUT PROBABLY MORE LIKELY TUE NIGHT INTO EARLY WED 
IN ADVANCE OF THE COLD FRONT...WITH POSSIBLY A COUPLE OF DEGREE RISE 
IN THE DRY SLOT ON WED AM...BEFORE MUCH COLDER AIR WORKS IN ON COLD 
ADVECTION ON WED AFTERNOON. AGAIN...GUSTS SHOULD BE AT THEIR PEAK IN 
THE DRY SLOT PERIOD. 

A WEAKER SYSTEM SHOULD APPROACH LATE IN THE PERIOD AND TRANSITION 
ACROSS THE AREA LATE IN THE PERIOD WITHIN A RATHER BROAD MEAN TROUGH
OVER MUCH OF THE EASTERN NOAM BEHIND A DEPARTED POTENT MIDWEEK
SYSTEM. THE COLDEST NIGHTTIME PERIOD APPEARS TO BE THU NIGHT WHEN
SOME CLEARING SHOULD FINALLY OCCUR AND A SFC HIGH MOVES INTO THE REGION.
LITTLE CHANGE WAS MADE BEYOND WED.

&&

.AVIATION.../18Z TO 18Z/...UPDATED

HIGH PRESSURE WILL CONTINUE TO SHIFT TO OUR EAST THROUGH THE PERIOD
WITH VFR CONDITIONS EXPECTED. HIGH/MID LEVEL CLOUDS WILL INCREASE
THROUGH THE NIGHT TONIGHT AS A WEAK FRONTAL BOUNDARY APPROACHES FROM
THE WEST. THE FRONT WILL PASS THROUGH EASTERN KENTUCKY ON MONDAY
ACCOMPANIED BY A LOWERING CLOUD BASE BELOW 10K FT MONDAY MORNING.
VIRGA... OR POSSIBLY A FEW SPRINKLES MAY ACCOMPANY THE FRONTAL
PASSAGE MONDAY MORNING... BUT LEFT ANY MENTION OF PRECIP OUT OF THE
TAFS AT THIS TIME. WINDS WILL REMAIN LIGHT... GENERALLY FROM THE
SOUTH TO SOUTHEAST.

&&

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

&&

$$

SHORT TERM...SCHOETTMER/ABE
LONG TERM....JP
AVIATION...ABE