Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 041505
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1005 AM EST THU FEB 4 2016

.UPDATE...
ISSUED AT 1005 AM EST THU FEB 4 2016

A THICK STRATUS CLOUD DECK REMAINS IN PLACE OVER THE ENTIRE CWA
THIS MORNING PER LATEST SATELLITE VISIBLE IMAGERY. SO HAVE
INCREASED SKY COVER FOR TODAY ALLOWING FOR SOME PARTIAL THINNING
OR CLEARING OF THE CLOUDS LATER THIS AFTERNOON/EVENING.
THOUGH...NOT SURE HOW QUICKLY THIS WILL OCCUR AS MODEL TIME
HEIGHTS ALL SHOW MOISTURE TRAPPED AT THE SFC THROUGH AT LEAST 00Z.
ALSO DID A QUICK REFRESH ON THE HOURLY TEMPS AND SENT UPDATED
GRIDS TO NDFD AND WEB SERVERS.

UPDATE ISSUED AT 648 AM EST THU FEB 4 2016

A LAYER OF LOW END VFR/HIGH END MVFR CLOUDS HAS SETTLED ACROSS THE
REGION...THOUGH STILL NO SIGNS OF SPRINKLES OR FLURRIES AS OF
EARLY THIS MORNING. BACK EDGE OF THIS CLOUD DECK IS CURRENTLY
MOVING INTO WESTERN KY...BUT MAY GET EXPEDITED SOMEWHAT BY DAYTIME
MIXING AS THE SUN COMES UP THIS MORNING...ALLOWING SKIES TO CLEAR
ACROSS PORTIONS OF THE REGION. OVERALL...FORECAST PARAMETERS SEEM
TO BE ON TRACK THIS MORNING WITH ONLY MINOR ADJUSTMENTS TO THE
TEMPS AND WINDS NEEDED AT THIS TIME. ANY CHANGES HAVE BEEN SAVED
AND SENT TO NDFD AND THE WEB...THOUGH NO NEW FORECAST PACKAGE IS
NEEDED AT THIS TIME.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 359 AM EST THU FEB 4 2016

HIGH PRESSURE HAS TAKEN HOLD OF THE REGION OVERNIGHT...WITH GOOD
COLD AIR ADVECTION IN PLACE. AS LOW END VFR CLOUDS BEGAN TO REBUILD
ACROSS THE REGION OVERNIGHT...IT WAS ORIGINALLY THOUGHT THAT THIS
CLOUD DECK MAY RESULT IN ENOUGH LLVL SATURATION TO PRODUCE SOME
SPRINKLE OR FLURRY ACTIVITY. HOWEVER...DEPTH OF MOISTURE IS LESS
THAN ORIGINALLY FORECASTED FROM THE MODELS...AND HAS THUS NOT
PRODUCED ANY PRECIP SO FAR. EVEN THE LATEST HI RES MODELS ARE NO
LONGER SHOWING ANY SIGNS OF SPRINKLES OR FLURRIES FOR THE
REMAINDER OF THE NIGHT OR MORNING. AS SUCH...WENT AHEAD AN REMOVED
ANY MENTION OF THIS FROM THE FORECAST.

OTHERWISE...HIGH PRESSURE SHOULD REMAIN IN CONTROL TODAY AND THROUGH
THE REMAINDER OF THE SHORT TERM. GENERALLY NW WINDS TODAY WILL
PROMOTE DRY AIR ACROSS THE REGION...ALONG WITH CONTINUED COOLING
CONDITIONS. DESPITE GENERALLY CLEARING SKIES...HIGH TEMPERATURES
WILL ONLY BE AROUND 40 BY THIS AFTERNOON...COMPARED TO THE RECORD
BREAKING MID 60 HIGHS YESTERDAY. CALM WINDS TONIGHT...AND
ABUNDANT RADIATIONAL COOLING WILL RESULT IN A GOOD RIDGE VALLEY
SPLIT OF TEMPERATURES...WITH GENERALLY LOW 20S ACROSS THE CWA. AS
HIGH PRESSURE TRANSITIONS EAST OF THE REGION THROUGH
TOMORROW...THIS COULD PROMOTE MORE SOUTHERLY FLOW ACROSS
KY...THOUGH STILL RELATIVELY LIGHT. THIS SHOULD BE ENOUGH TO BOOST
TEMPS BACK INTO THE MID 40S WITH A GENERAL WARMING TREND EXPECTED
THROUGH THE WEEKEND.

.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU FEB 4 2016

WHILE THE MODELS ARE IN AGREEMENT ALOFT...IN THE BROADEST SENSE...
THROUGH THE EXTENDED PORTION OF THE FORECAST...THEY ARE FAR FROM
MESHING WITH THE SHORTER WAVE DETAILS...PARTICULARLY AFTER THE
WEEKEND. LEADING UP TO THE WEEKEND...THEY ALL PUSH A BRIEF RIDGE
OVER THE TENNESSEE VALLEY INTO SATURDAY BEFORE SWEEPING A SOUTHERN
STREAM TROUGH THROUGH THE DEEP SOUTH...ALONG THE GULF COAST AND
OFFSHORE OF FLORIDA. THE MODELS ARE IN FAIR AGREEMENT WITH THIS
LOW...THOUGH THE GFS IS NOW THE WEAKEST AND FASTEST WHILE THE
ECMWF AND CANADIAN MATCH UP BETTER. WHILE THAT SOUTHERN LOW IS
PASSING...A NORTHERN STREAM ONE MOVES BY TO THE NORTH OF KENTUCKY
WITH JUST SOME WEAK ENERGY SLIPPING THROUGH OUR STATE INTO SUNDAY
MORNING. STRONG RIDGING OVER THE WEST COAST WILL THEN PROMPT A
FULL LATITUDE TROUGH TO TAKE SHAPE OVER THE CENTRAL PLAINS...
DROPPING INTO THE MIDWEST AND MID MISSISSIPPI VALLEY BY MONDAY
MORNING. THIS THE MODELS AGREE UPON...WITH THE ECMWF THE
STRONGEST. IN FACT...THE ECMWF TAKES THE CORE OF THIS DEVELOPING
LOW INTO THE OHIO VALLEY AND ACROSS KENTUCKY MONDAY INTO TUESDAY
WITH AN EQUALLY STRONG...BUT BROADER...TROUGH FROM THE GFS
COVERING THE ENTIRE OHIO VALLEY. THIS HIGHLY AMPLIFIED SOLUTION
PORTENDS AN ACTIVE PERIOD OF WINTER WEATHER FOR THE REGION THROUGH
WEDNESDAY MORNING BEFORE THE WHOLE TROUGH QUICKLY FILLS AND GETS
SHUNTED OFF TO THE EAST WHEN THE WESTERN RIDGE STARTS TO FLATTEN
AND SEEP SOUTHEAST. SEEMINGLY MINOR DETAILS AROUND THE TROUGH/LOW
DURING THE START OF NEXT WEEK WILL MAKE FOR A COMPLICATED FORECAST
AT THE SFC AND WITH WX DETAILS. AS SUCH...A GENERAL MODEL BLEND
REMAINS THE PREFERRED STARTING POINT FOR THE EXTENDED GRIDS.

SENSIBLE WEATHER WILL FEATURE A MOSTLY DRY AND SLOWLY MODERATING
AREA OF HIGH PRESSURE OVER THE REGION THROUGH THE WEEKEND AS IT IS
SQUEEZED BETWEEN A SYSTEM TO THE SOUTHEAST AND ONE DEVELOPING TO
THE NORTHWEST. FOR SUNDAY NIGHT INTO MONDAY...THE NORTHWEST SFC
LOW WILL DEEPEN OVER A BROAD EXPANSE ENCOMPASSING THE OHIO VALLEY
AND DOWN OVER THIS PART OF KENTUCKY. QUESTIONS REMAIN ABOUT THIS
EVOLUTION LOCALLY AND ITS INTERACTION WITH A COASTAL SFC LOW. FOR
NOW WILL CONTINUE TO SPLIT THE DIFFERENCE AND FOCUS ON THE CLEARER
INDICATIONS OF A COLDER TURN TO THE WEATHER AND SOLID CHANCES FOR
SNOW SHOWERS FOR OUR AREA FROM MONDAY NIGHT INTO TUESDAY AND
POSSIBLY CONTINUING INTO WEDNESDAY. AMOUNTS ARE FAR MORE TRICKY
AS THE QPF WILL BE HIGHLY DEPENDENT ON THE COASTAL INTERACTION AND
COULD TURN OUT RATHER PALTRY WITHOUT A SOLID CONNECTION TO THE
EAST COAST WATERS. WILL CONTINUE TO MENTION THE POTENTIAL FOR
ACCUMULATING SNOW IN THE HWO FOR THE START OF THE WORK WEEK...BUT
CONFIDENCE REMAINS UNSATISFYINGLY LOW FOR AN EVENT THAT IS JUST A
HANDFUL OF DAYS AWAY.

AGAIN ADJUSTED THE GRIDS FROM THE CR INIT MAINLY TO ACCOUNT FOR
A DECENT RIDGE TO VALLEY TEMPERATURE DIFFERENCES THROUGH THE
WEEKEND. ALSO...TWEAKED THE POP GRIDS LATER IN THE PERIOD TO
REFLECT A REASONABLE AMALGAMATION OF THE OPERATIONAL GFS AND
ECMWF SOLUTIONS.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 654 AM EST THU FEB 4 2016

A DECK OF LLVL STRATUS CONTINUES ACROSS MUCH OF KY AS OF 12Z THIS
MORNING...WITH THE BACK EDGE NOW STARTING TO PUSH INTO FAR WESTERN
KY. EXPECT GENERALLY LOW END VFR CIGS TO CONTINUE THROUGH THE
MORNING...WITH SOME BRIEF PERIODS OF HIGH END MVFR POSSIBLE. AS
THE SUN CONTINUES TO RISE THIS MORNING...EXPECT SOME MIXING TO
ALSO HELP MIX OUT BKN CLOUD COVER...WITH GENERALLY SCT SKIES
EXPECTED BY 15/16Z. EXPECT OVERALL CLEARING TO START OCCURRING LATE
TONIGHT TOWARDS THE END OF THE TAF PERIOD...ACCORDING TO THE
LATEST NAM 12 MODELS. LIGHT NW WINDS GENERALLY LESS THAN 10 KNOTS
SHOULD REMAIN THROUGHOUT THE FORECAST PERIOD AS WELL.

&&

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

$$

UPDATE...JVM
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW



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