Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 240954
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
454 AM EST WED DEC 24 2014

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 316 AM EST WED DEC 24 2014

AREA OF LOW PRESSURE IS NOW STARTING TO MAKE ITS MOVE NORTH ACROSS
CENTRAL KENTUCKY...AND WILL END UP OVER SOUTHEAST MICHIGAN BY THIS
EVENING. STRONG LIFT ASSOCIATED WITH THE LOW PRESSURE SYSTEM WILL
SPREAD ACROSS THE AREA THROUGH DAYBREAK WITH RAIN BECOMING WIDESPREAD
ONCE AGAIN AFTER A BRIEF LULL OVER THE PAST FEW HOURS. HRRR AND RAP
ARE IN GOOD AGREEMENT THAT THIS LIFT WILL EXIT TO THE NORTH BY 9 OR
10 AM...WITH ANOTHER LULL IN PRECIPITATION EXPECTED THROUGH MIDDAY.
WITH THE MIDDAY LULL IN PRECIPITATION...HIGHS WILL WARM INTO THE 60S
FOR ONE MORE DAY.

FINALLY AS THE LOW SHIFTS NORTH THOUGH...A STRONG COLD FRONT WILL
PUSH EAST ACROSS THE AREA THIS AFTERNOON. WITH THE MILD
TEMPERATURES...WE MAY GENERATE SOME WEAK INSTABILITY TO SUPPORT
CONVECTIVE SHOWERS DEVELOPING ALONG THE FRONT AS IT PUSHES ACROSS THE
AREA. WHILE THUNDER CHANCES REMAIN LOW...CANNOT RULE OUT SOME THUNDER
WITH THE STRONGER CELLS...ESPECIALLY ACROSS NORTHERN KENTUCKY. GIVEN
THE ABUNDANCE OF MID LEVEL DRY AIR...AND STRONG 850MB WINDS AROUND 45
KNOTS...WE COULD SEE THE POTENTIAL FOR SOME HIGHER WINDS TO GET MIXED
DOWN WITH THE SHOWERS. HOWEVER...EVEN WITHOUT THE CONVECTIVE SUPPORT
FOR WINDS...THE SYNOPTIC SETUP BEHIND THE FRONT SHOULD SUPPORT 40+
MPH WINDS...ESPECIALLY ACROSS THE NORTHERN HALF OF THE AREA.
THUS...WILL GO AHEAD WITH A WIND ADVISORY FOR THE NORTHERN HALF OF
THE AREA. CONDITIONS ARE MORE MARGINAL FARTHER SOUTH...BUT A WIND
ADVISORY FOR THE HIGH TERRAIN NEAR THE VIRGINIA BORDER ALSO SEEMS IN
ORDER GIVEN THE STRONG WINDS AT 850MB. BEST THREAT FOR THE HIGHER
WINDS WILL BE AFTER 17Z AND BEFORE 03Z TONIGHT.

CONDITIONS WILL QUITE DOWN SOME THIS EVENING AS SUBSIDENCE SPREADS IN
BEHIND THE DEPARTING FRONT. HOWEVER...A SHORTWAVE TROUGH WILL PUSH
EAST ACROSS THE AREA LATE TONIGHT...WITH THE MOISTURE DEPTH
INCREASING TO SUPPORT SOME LIGHT RAIN/DRIZZLE. COLDER AIR WILL ALSO
BE SPILLING INTO THE AREA TONIGHT BEHIND THE FRONT. WHILE MOST AREAS
WILL STAY MILD ENOUGH FOR JUST RAIN...THE HIGHER TERRAIN IN THE
SOUTHEAST WILL SUPPORT SOME SNOW CHANCES. IN FACT...CONDITIONS ALIGN
GOOD ENOUGH TONIGHT WE COULD SEE A LIGHT COATING OF SNOW ON THE HIGH
TERRAIN ABOVE 2500 FEET LATE TONIGHT.

HEIGHTS WILL BE QUICK TO BUILD BACK ACROSS THE AREA ON CHRISTMAS.
CLOUDS MAY BE STUBBORN THROUGH THE FIRST HALF OF THE DAY...BUT WE
SHOULD DEFINITELY SEE A DECREASING TREND THROUGH THE AFTERNOON AND
EVENING AS THE RIDGE CENTERS ITSELF OVER THE REGION. HIGHS WILL
STRUGGLE TO WARM GIVEN THE ABUNDANCE OF CLOUDS THROUGH THE FIRST HALF
OF THE DAY...SO PLAN TO KEEP HIGHS LIMITED TO THE LOW TO MID 40S WITH
30S ON THE HIGHER TERRAIN IN THE SOUTHEAST.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 420 AM EST WED DEC 24 2014

THE PERIOD IS EXPECTED TO BEGIN WITH A CLOSED UPPER LOW CONTINUING TO
DEPART TO THE NORTHEAST OF THE REGION WITH UPPER LEVEL RIDGING
BUILDING ACROSS THE AREA AT THE START OF THE PERIOD. FURTHER TO THE
WEST A TROUGH IS EXPECTED TO EXTEND FROM THE NORTHERN PLAINS SOUTH
INTO THE SOUTHERN ROCKIES AND NORTHERN MEXICO. SFC AND UPPER LEVEL
RIDGING WILL GRADUALLY WORK ACROSS THE AREA FOR THU NIGHT INTO FRIDAY
AND THEN DEPART TO THE EAST FRIDAY NIGHT INTO SATURDAY. MEANWHILE A
SHORTWAVE TROUGH IS ANTICIPATED TO EJECT FROM THE WESTERN TROUGH
ACROSS THE PLAINS TOWARD THE GREAT LAKES FROM FRIDAY INTO SATURDAY.
THIS WILL LEAD TO GRADUALLY LOWERING HEIGHTS ACROSS THE GREAT LAKES
AND OH VALLEY AND A COLD FRONT DROPPING TOWARD THE REGION TO START
THE WEEKEND. THIS SHOULD BEGIN THE START OF AN UNSETTLED PERIOD.

OVER TIME...A RATHER BROAD TROUGH IS EXPECTED TO DEVELOP FROM CENTRAL
CANADA SOUTH INTO THE ROCKIES AND THEN EAST INTO THE EASTERN CONUS.
MODELS VARY FROM RUN TO RUN AND MODEL TO MODEL WITH THE HANDLING OF
INDIVIDUAL SHORTWAVES IN WEST SOUTH TO SOUTHWEST FLOW DURING THIS
PERIOD AND THE INTERACTION WITH A BAROCLINIC ZONE...THE FRONT THAT
MOVES INTO THE AREA EARLY IN THE WEEKEND...RESULTING IN SFC WAVES
DEVELOPING ALONG THE FRONT. THE ECMWF IS GENERALLY SLOWER BRINGING
THIS FRONT ACROSS THE AREA AND IS ALSO STRONGER AND FURTHER SOUTHEAST
WITH A SFC WAVE SUN NIGHT INTO MONDAY. AS THIS LAST SYSTEM DEPARTS AN
ARCTIC BOUNDARY SHOULD APPROACH THE AREA TUE OR WED.

DUE TO AN OVERALL LACK OF COLDER AIR FOR MOST OF THE PERIOD...MUCH OF
THE PRECIPITATION SHOULD FALL AS RAIN...ALTHOUGH SOME SNOW MAY MIX IN
ON SUNDAY NIGHT INTO EARLY ON MONDAY IN THE HIGHEST TERRAIN AND NORTH
OF THE MTN PARKWAY. A MIX OF RAIN AND SNOW WILL REMAIN POSSIBLE INTO
THE DAY ON TUESDAY AS WE HELD ONTO SLIGHT CHANCE POPS TO ACCOUNT FOR
THE ECMWF RUN. BOTH THE GFS AND ECMWF RUNS SUPPORT A WET END TO THE
WEEKEND.

AS FOR TEMPERATURES...THE PATTERN FAVORS A RIDGE VALLEY TEMPERATURE
SPLIT ON THU NIGHT AS SKIES WILL HAVE CLEARED OR SHOULD BE CLEARING
AS SFC AND UPPER LEVEL RIDGING WORK INTO THE AREA. A RELATIVELY DRY
AIRMASS AND A DOWNSLOPE COMPONENT SHOULD LEAD TO A RATHER MILD DAY ON
FRIDAY...ESPECIALLY FOR VALLEYS NEAR THE VA BORDER. THE DEPARTING
RIDGE SHOULD AGAIN FAVOR MILDER LOWS ON FRI NIGHT...BUT YET ANOTHER
RIDGE/VALLEY SPLIT. SATURDAY SHOULD AGAIN BE MILD AHEAD OF THE
BOUNDARY. WITH THE BAROCLINIC ZONE OVER OR NEAR THE REGION A GENERALLY
NW TO SOUTH OR SOUTHEAST GRADIENT IN TEMPERATURES IS ANTICIPATED FOR
THE REMAINDER OF THE PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 228 AM EST WED DEC 24 2014

MVFR CIGS HAVE DISSIPATED OVERNIGHT AS DOWNSLOPING FLOW HAS TAKEN
OVER IN THE PRESENT WEAKLY FORCED ENVIRONMENT. ONE MORE ROUND OF
SHOWERS WILL PUSH NORTH LATE TONIGHT INTO THE MORNING HOURS AND MAY
BRING SOME MVFR CIGS AND VISIBILITIES. HOWEVER...AGAIN THIS SHOULD
NOT BE PERSISTENT. A COLD FRONT WILL THEN SURGE EAST ACROSS THE AREA
THIS AFTERNOON AND EVENING...WITH A PERIOD OF GUSTY SOUTHWEST WINDS
ANTICIPATED. THIS MAY ALSO BRING A FEW SHOWERS WITH IT. IN THE WAKE
OF THE FRONT...CIGS SHOULD LOWER BACK TO MVFR AND CONTINUE INTO
TONIGHT...POSSIBLY BORDERING ON IFR CONDITIONS AT TIMES. AFTER A LULL
IN PRECIPITATION INTO THE LATE EVENING HOURS...RAIN WILL REDEVELOP
LATE TONIGHT...WITH SOME SNOW POSSIBLY MIXING IN ABOVE 2500 FEET.


&&

.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TODAY TO 10 PM EST THIS EVENING FOR
KYZ044-050>052-058>060-068-069-088-104-106>112-114-118>120.

&&

$$

SHORT TERM...KAS
LONG TERM...JP
AVIATION...KAS





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