National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KJKL 100415 AAC
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
1115 PM EST TUE FEB 9 2010

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

THE COLDER AIR HAS COME IN A BIT QUICKER THAN THE PREVIOUS FORECAST.
WITH THAT IN MIND AND ALSO FOR TIMING PURPOSES...RAISED WIND GUST
SPEEDS BASED ON OBS AND HAVE MADE SOME MINOR ADJUSTMENTS TO THE FIRST
PERIOD WORDING AND WX. OTHERWISE...NO FURTHER CHANGES. AN UPDATED WSW
WILL BE ISSUED SHORTLY.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/THE REST OF TONIGHT THROUGH WEDNESDAY/

A BAND OF SNOW SHOWERS ALONG THE LEADING EDGE OF HIGHER LAPSE RATES
IN THE WAKE OF AN ARCTIC COLD FRONT OR NEAR A POOL OF VERY COLD 8H AIR
WITH 8H TEMPS IN THE -15C TO -18C RANGE WILL MOVE ACROSS THE REGION
THIS EVENING. IN FACT...A LULL IN COVERAGE MAY OCCUR BEHIND THIS
BAND BEFORE THE UPPER LOW MOVES ACROSS THE AREA. AS THE UPPER LOW
BEGINS TO WORK PAST THE AREA LATER TONIGHT AND ON WEDNESDAY MOISTURE
DRAWN WEST FROM THE ATLANTIC SYSTEM AS WELL AS A FETCH OF MOISTURE
OFF OF THE GREAT LAKES WILL BRING ENOUGH LOW LEVEL MOISTURE COMBINED
WITH COLD TEMPS WITHIN THE MOIST LAYER AND UPSLOPE FLOW FOR ADDITIONAL
SNOW SHOWERS ON WED. THE RECENT MODEL RUNS FAVOR THE MORE WIDESPREAD
AND INTENSE SNOW SHOWERS WHERE DEEPER MOISTURE SHOULD RESIDE LATER
TONIGHT AND ON WED OR GENERALLY IN THE WINTER STORM WARNING AREA.
OPTED TO RAISE POPS THIS EVENING AS WELL AS LATER TONIGHT AND ON
WEDNESDAY.

IN ADDITION...PLENTY OF HIGHER MOMENTUM FROM STRONGER WINDS ALOFT
WILL BE MIXED DOWN IN SNOW SHOWERS AND SNOW SQUALLS LATER TONIGHT AND
ON WEDNESDAY WITH GUSTS IN THE 30 TO 40 MPH POSSIBLE AT TIMES...ESPECIALLY
IN ANY SQUALLS. OPTED TO ADD A CHANCE OF SNOW SQUALLS TO THE FORECAST
AS WELL AS THE THREAT OF BLOWING SNOW FROM LATER TONIGHT THROUGH
WEDNESDAY.

OPTED TO ADD HARLAN AND LETCHER COUNTIES TO THE WINTER STORM WARNING.
18Z MODEL QPF IS ON THE ORDER OF 0.2 TO 0.3"+ IN THAT AREA. WITH SUCH
COLD AIR ALOFT THE REST OF THE SNOW THAT FALLS WILL BE DRY AND FLUFFY
WITH AT LEAST A RATIO OF 30:1 IF NOT 40:1 ABOVE 2500 FEET. AT THIS
POINT IT APPEARS THAT 3 TO 5 INCHES SHOULD FALL IN THE LOWER ELEVATIONS
OF HARLAN AND LETCHER COUNTIES WITH 4 TO 10 INCHES ACROSS THE HIGHER
ELEVATIONS WITH THE HIGHEST TOTALS CONFINED TO THE HIGHER POINTS ON
BLACK MOUNTAIN AND PINE MOUNTAIN. THESE TOTALS ARE THROUGH DAWN ON
THURSDAY.

THE PREVIOUS SHORT TERM FORECAST DISCUSSION FOLLOWS...

/TONIGHT THROUGH WEDNESDAY NIGHT/

...ROUND 2 OF THE WINTER STORM WILL COMMENCE THIS EVENING...

CURRENTLY...WARM SECTOR IS MOVING OUT OF THE AREA WITH ARCTIC COLD
FRONT ALREADY ENTERING INTO OUR WESTERN CWA. LATEST OBS SHOW KSME
WITH WEST WINDS GUSTING TO 20 MPH. UPSTREAM COLD AIR IS POISED TO
MOVE INTO THE REGION AS UPPER LOW MOVES ACROSS THE OHIO VALLEY.
EXPECT ANY LINGERING RAIN SHOWERS TO TRANSITION TO SNOW SHOWERS LATE
THIS AFTERNOON AND EVENING...WITH A RELATIVE LULL UNTIL MIDNIGHT
BEFORE UPSLOPE KICKS IN AFTER MIDNIGHT. EXPECT SNOW SHOWERS
LINGERING THROUGH THE END OF THE FORECAST PERIOD THEREAFTER.

AS FAR AS THE CURRENT HEADLINES ARE CONCERNED...WILL LEAVE THE
CURRENT WARNING AND ADVISORY AS IS TO ACCOUNT FOR BLOWING AND
DRIFTING SNOW IMPACTS LATE TONIGHT AND EXTEND THROUGH WEDNESDAY
NIGHT. OVERALL...EXPECT MOSTLY ADVISORY CRITERIA SNOWS THROUGH THE
END OF THIS PERIOD...HOWEVER SOME TOTALS COULD PILE UP BY THE TIME
THURSDAY MORNING ROLLS AROUND. WEST OF A MOREHEAD TO JACKSON TO
MIDDLESBORO COUNTY LINE A GENERAL 2 TO 5 INCHES WILL BE POSSIBLE
BETWEEN TONIGHT AND DAWN ON THURSDAY. FURTHER EAST AND IN THE HIGH
TERRAIN...A GENERAL 4 TO 8 INCHES CAN BE EXPECTED WITH LOCALLY HIGHER
AMOUNTS POSSIBLE IN THE HIGHEST TERRAIN. AGAIN...THIS SNOWFALL WILL
NOT FALL ALL AT ONCE BUT OVER A 36 TO 48 HOUR PERIOD. THESE TOTALS
SHOULD BE ENHANCED BY ATLANTIC MOISTURE BEING WRAPPED AROUND THE BACK
SIDE OF THIS SYSTEM...THEREFORE EXPECTING A BIT MORE THAN JUST A
NORMAL UPSLOPE TYPE OF EVENT. ALSO...LAKE MICHIGAN IS BEHIND FROZEN
AREA FOR THIS TIME OF YEAR AND MOISTURE ENHANCEMENT IS NOT SHUT OFF.

THE BIGGEST IMPACTS FROM THIS STORM WILL MOSTLY BE FELT FROM DAWN
TOMORROW THROUGH THE DAY AS WINDS SHOULD BE AROUND 20 MPH WITH GUSTS
UP TO 35 MPH. BLOWING AND DRIFTING SNOW SHOULD REDUCE VISIBILITIES
ALONG WITH WIND CHILL VALUES IN THE SINGLE DIGITS BY TOMORROW MORNING.
WITH RAPID COOLING LATER THIS EVENING AND TONIGHT AND SNOW COMMENCING
FEEL THAT WET ROADWAYS COULD FREEZE QUICKLY WITH SLUSHY MIX OR ICE.
THIS SNOW WILL NOT BE HEAVY AND WET...THEREFORE IMPACTS TO POWER
LINES AND TREES SHOULD BE MINIMAL. UPDATED LONG TERM DISCUSSION WILL
BE OUT SHORTLY.

.LONG TERM.../THURSDAY THROUGH TUESDAY/

THE UPPER LEVEL PATTERN THROUGH THE EXTENDED PORTION OF THE FORECAST
IS GENERALLY COMING INTO BETTER AGREEMENT WITH THE MAIN FEATURES TO
AFFECT THE REGION. IN THE WAKE OF THE MAJOR TROUGH EXITING OFF THE
EAST COAST...ON THURSDAY...HEIGHTS WILL RISE OVER KENTUCKY AS THE
PATTERN TEMPORARILY FLATTENS. A SOUTHERN STREAM TROUGH WILL MOVE INTO
CENTRAL TEXAS BY 00Z FRIDAY WITH THE NAM LAGGING THE OTHER MODELS.
THIS WAVE COMES EAST ALONG THE CENTRAL GULF COAST ON FRIDAY WITH THE
EXCESSIVELY DEEP GEM AND WEAKER GFS TRAILING THE ECMWF. MEANWHILE...A
NORTHERN STREAM CLIPPER SHORTWAVE IS DROPPING SOUTH FROM CENTRAL
KENTUCKY INTO THE NORTHERN PLAINS. FOR FRIDAY INTO FRIDAY NIGHT THE
SOUTHERN STREAM WAVE WEAKENS AS IT RIDES EAST ACROSS THE DEEP SOUTH.
THE GEM IS THE FURTHEST NORTH WITH THIS...LIKELY DUE IN PART TO ITS
NORTHERN STREAM WAVE BEING THE SLOWEST AND FURTHEST NORTHWEST OF ALL
THE MODELS. HAVE GONE WITH A BLEND OF THE ECMWF AND GFS FOR THIS
SOUTHERN WAVE. ONCE THIS BRUSHES BY TO THE SOUTHEAST...ATTENTION THEN
TURNS TO THE NORTHERN CLIPPER DROPPING INTO THE UPPER MIDWEST. THE
MODELS ALL HAVE THIS AS A...FAIRLY SIMILAR IN STRENGTH...COMPACT LOW
WITH THE ECMWF THE QUICKEST AND THE GEM LAGGING BEHIND. THIS CLIPPER
THEN PIVOTS SOUTHEAST INTO THE OHIO VALLEY WITH THE GFS THE MIDDLE
SOLUTION BETWEEN THE QUICKER AND MORE EASTERLY ECMWF. CONTINUE TO
FOLLOW A BLEND OF THESE TWO...DISCOUNTING THE VERY WEST AND SLOW
GEM. FOR SUNDAY...THE GFS IS THE STRONGEST BRINGING THE CORE OF THE
CLIPPER THROUGH KENTUCKY WITH THE ECMWF WEAKENING IT AS IT SLIPS
EAST. IN THE WAKE OF THIS SYSTEM...A LARGE TROUGH WILL HOLD COURT
OVER THE NORTHEAST QUADRANT OF THE COUNTRY THROUGH TUESDAY WITH
ANOTHER CLIPPER LOOKING TO DROP INTO THE AREA LATE IN THE DAY.

SENSIBLE WEATHER WILL FEATURE THE LINGERING SNOW SHOWERS OVER OUR
HIGHER TERRAIN IN THE EAST TAPERING OFF BY EVENING...THURSDAY. COLD
HIGH PRESSURE THEN SETTLES INTO THE REGION THROUGH FRIDAY AS A
SOUTHERN STREAM LOW ROLLS EAST ALONG THE GULF COAST. THIS WILL BRUSH
BY TO THE SOUTH ON FRIDAY WITH A CLIPPER DEVELOPING OVER THE UPPER
MIDWEST AND TAKING AIM ON THE AREA FOR THE WEEKEND. WITH STILL SOME
UNCERTAINTY ON TIMING FOR THIS NEXT...SOUTHEAST BOUND...SYSTEM HAVE
INTRODUCED LOW POPS FOR THE LATTER PART OF FRIDAY INTO SATURDAY. PUT
THE MAIN POPS IN WITH THIS CLIPPER FOR SATURDAY NIGHT INTO SUNDAY.
THIS COMES IN COLD ENOUGH FOR ALL SNOW AND ALSO SERVE TO REINFORCE
THE ARCTIC AIR IN PLACE. THE CLIPPER WILL GRADUALLY MOVE EAST AS THE
LARGE TROUGH CONTINUES TO SUPPORT A SMALL THREAT FOR SNOW SHOWERS
INTO MONDAY...PARTICULARLY IN THE NORTHEAST AND OUR HIGHER TERRAIN
COUNTIES NEAR VIRGINIA. HIGH PRESSURE WILL THEN BUILD IN TEMPORARILY
MONDAY NIGHT AND INTO TUESDAY...JUST AHEAD OF ANOTHER POTENTIAL
CLIPPER DEVELOPING OVER THE UPPER MIDWEST AND HEADED THIS WAY.

FOR THE MOST PART FOLLOWED A MODIFIED VERSION OF THE TEMPERATURE
GUIDANCE FROM HPC...GOING A BIT LOWER FOR LOWS EARLY IN THE
FORECAST GIVEN THE ANTICIPATED SNOW COVER. AS FOR POPS...ALSO ENDED
UP SIMILAR TO A BLEND OF THE MEX AND HPC VALUES THROUGH THE PERIOD.

&&

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

AN ARCTIC FRONTAL BOUNDARY IS CURRENTLY MARCHING THROUGH EASTERN
KENTUCKY. PRECIPITATION ALONG AND BEHIND THIS BOUNDARY IS ALL SNOW.
THE TAF SITES ARE SEEING MVFR CONDITIONS IN LIGHT SNOW AS OF TAF
ISSUANCE. AS MORE AND MORE ARCTIC AIR SPILLS INTO THE AREA BEHIND THE
DEPARTING FRONT...THE MORE WIDESPREAD AND INTENSE THE SNOW SHOWERS WILL
BECOME. WINDS WILL VEER TO AND THEN INCREASE OUT OF THE WEST...THEN
NORTHWEST AND BECOME QUITE GUSTY BEHIND THE FRONT. CIGS AND VSBYS
WILL THEN DROP BACK DOWN INTO THE IFR RANGE AS PRECIPITATION BECOMES
MORE SHOWERY IN NATURE...AND THE SNOW BEGINS BLOWING AROUND A BIT.
THE MAIN CONCERN FOR LATER TONIGHT THROUGH TOMORROW WILL BE SURFACE
WINDS AS THE SUSTAINED COMPONENT INCREASES TO 15-20 KTS...WITH GUSTS
TO BETWEEN 30 AND 35 KTS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR KYZ044-052-088-
104-106-107-109-110-118>120.

WINTER WEATHER ADVISORY UNTIL 7 AM EST THURSDAY FOR KYZ050-051-
058>060-068-069-079-080-083>087-108-111>117.

&&

$$

SHORT TERM...SCHOETTMER/JP
LONG TERM....GREIF
AVIATION...AR