Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 251920
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
320 PM EDT FRI JUL 25 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 320 PM EDT FRI JUL 25 2014

HIGH PRESSURE WILL RULE OUR WEATHER TONIGHT. NORTHWEST FLOW ALOFT
WILL TRANSPORT DEBRIS CLOUDS FROM THE THUNDERSTORM COMPLEX WELL TO
OUR WEST OVER OUR AREA LATER THIS AFTERNOON INTO THE OVERNIGHT
HOURS. THESE CLOUDS WILL HELP TO LIMIT FOG FORMATION TONIGHT AND
HELP KEEP TEMPS GENERALLY IN THE UPPER 50S TO LOWER 60S.

THE NORTHWEST FLOW PATTERN ALOFT WILL EASE UP BRIEFLY ON SATURDAY
BEFORE REAMPLIFYING AGAIN FOR THE SECOND HALF OF THE WEEKEND.
SHORTWAVE RIDGING AND A RETURN TO SOUTHWEST FLOW IN THE LOW LEVELS
WILL BOOST TEMPS DURING THE DAY INTO THE UPPER 80S TO NEAR 90.
DEWPOINTS WILL STAY BEARABLE DURING THE DAY...BUT BEGIN TO CLIMB
BACK TOWARD 70 SATURDAY NIGHT. THUNDERSTORM ACTIVITY ASSOCIATED WITH
AN ADVANCING COLD FRONT OVER THE UPPER MIDWEST AND GREAT LAKES IS
EXPECTED TO SLOWLY SAG SOUTHEASTWARD ACROSS THE OHIO VALLEY
SATURDAY. WILL INCLUDE A SLIGHT CHANCE OF A STORM LATE IN THE DAY
ALONG AND NORTH OF I-64. THUNDERSTORMS CHANCES WILL THEN INCREASE
FROM NORTH TO SOUTH SATURDAY NIGHT WITH THE POSSIBILITY OF A
THUNDERSTORM COMPLEX DROPPING INTO THE AREA. STILL CONSIDERABLE
UNCERTAINTY WITH THE PLACEMENT AND POTENTIAL STRENGTH OF THIS
SYSTEM...BUT AREAS NORTH OF JKL STAND THE BEST CHANCE OF SEEING
STORMS BEFORE DAWN ON SUNDAY.

.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 357 AM EDT FRI JUL 25 2014

AN AMPLIFIED LONG WAVE TROUGH WILL BE THE MAIN WEATHER PLAYER DURING
THE EXTENDED FORECAST. A CLOSED UPPER LEVEL LOW OVER NE CANADA WILL
SLOWLY PUSH SOUTHWARD DURING THE COURSE OF THE EXTENDED
PERIOD...WITH SEVERAL SHORTWAVES FOLLOWING THE LONG WAVE
PATTERN...DRIVING OUR TEMPS AND PRECIP. THE FIRST OF THESE
SHORTWAVES WILL MOVE INTO THE GREAT LAKES BY SUNDAY AFTERNOON. AT
THE SURFACE...A LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
BE JUST AHEAD OF THE SHORTWAVE...PUSHING SE AS THE SHORTWAVE
PROGRESSES. WARM HUMID AND UNSTABLE AIR WILL FILTER INTO THE REGION
WELL AHEAD OF THE COLD FRONT...ALLOWING CONVECTION TO BEGIN AS EARLY
AS 6 TO 12Z SUNDAY. IT SEEMS AS THOUGH THE LATEST MODELS ARE BACKING
OFF ON THE START TIME OF THE PRECIP...SO THE ABOVE MENTIONED TIME
HAS BEEN PUSHED BACK SLIGHTLY FROM THE PREVIOUS FORECAST. IN GOOD
NEWS...ALL THE MID RANGE MODELS SEEM TO BE IN DECENT AGREEMENT WITH
THIS SYSTEM...BOOSTING CONFIDENCE IN THIS LATER ONSET TIME.

LOOKING AT THE LATEST FORECAST SOUNDINGS...STILL SUPPORTIVE OF A
POSSIBLE SEVERE THREAT BY AFTERNOON/EVENING SUNDAY...WITH STEEP
LAPSE RATES...CAPE VALUES 3-4.5 J/KG...STRONG WINDS IN BOTH THE MID
AND UPPER LEVELS...AND DRYING IN THE MID LEVELS. NOT TO MENTION PWAT
AMOUNTS WILL BE CLOSE TO 2 INCHES /1.93 FOR PIKEVILLE ACCORDING TO
THE LATEST NAM/ FOR A 6 HOUR PERIOD BY SUNDAY AFTERNOON. NAM IS
TRENDING SLIGHTLY HIGHER ON THE WATER CONTENT COMPARED TO THE
GFS...BUT BOTH ARE STILL CONCERNEDLY HIGH FOR POSSIBLE FLASH
FLOODING THREATS AS WELL. SPC HAS ALSO PUT MUCH OF KY AND POINTS TO
THE E/NE IN A DAY 3 SLIGHT RISK FOR SEVERE THUNDERSTORMS AS WELL.

THE UPPER LEVEL SHORTWAVE WILL MOVE TO OHIO BY 12Z MONDAY...WHILE
THE SURFACE FRONT WILL HAVE PUSHED SE OF THE REGION. BOTH DRIER AND
COOLER AIR WILL BEGIN FILTERING IN TO KY AS HIGH PRESSURE MOVES IN
OVERHEAD. HOWEVER...WITH THE LINGERING INFLUENCE OF THE
SHORTWAVE...AS WELL AS SOME LINGERING LOW LEVEL MOISTURE...THERE IS
CONTINUED SUPPORT FOR SOME ISL/SCT SHOWERS AND TSTORMS REOCCURRING
DURING THE AFTERNOON HOURS MONDAY. ONCE THE SHORTWAVE FINALLY MOVES
WELL EAST OF THE REGION AND DRIER AIR CONTINUES TO TAKE HOLD...AND
WE LOSE DIURNAL HEATING INFLUENCE...EXPECT ANY PRECIP CHANCES TO BE
CUT OFF BY MONDAY NIGHT.

THE WEATHER FOR BOTH TUESDAY AND WEDNESDAY LOOK GREAT...AND VERY
UNSEASONABLE. THE LONGWAVE TROUGH...HAVING DROPPED SOUTHWARD...WILL
ALLOW UNSEASONABLY COOL TEMPERATURES TO ADVECT INTO THE REGION.
WHILE HIGHS MONDAY WILL BE IN THE MID AND UPPER 70S...BY TUESDAY
THEY WILL HAVE DROPPED FURTHER...INTO THE LOW 70S FOR MUCH OF
EASTERN KY. AIRMASS MODIFICATION AND ABUNDANT SUNSHINE WILL ALLOW
TEMPERATURES TO MODERATE SOME BY WEDNESDAY...BUT STILL EXPECT A COOL
UPPER 70S TO AROUND 80. AND WITH SURFACE HIGH PRESSURE STILL IN
PLACE...AND DRY NRLY WINDS...PRECIP CHANCES WILL BE VIRTUALLY NIL.

SADLY ALL GOOD THINGS MUST COME TO AN END. MODELS START TO LOSE
AGREEMENT THIS FAR OUT IN THE FORECAST...BUT GENERAL CONSENSUS IS
THAT SOME DIURNAL CONVECTION WILL START TO KICK BACK IN BY AFTERNOON
THURSDAY ALONG THE HIGHEST TERRAIN...AS DEEPER MOISTURE SITS TO OUR
SE. THEN THERE IS THE POTENTIAL FOR ANOTHER SHORTWAVE TO IMPACT THE
REGION BY FRIDAY...BRINGING MORE WIDESPREAD CHANCES FOR CONVECTION.
CONFIDENCE IN BOTH OF THESE IS STILL QUITE LOW AT THIS POINT GIVEN
THE MODEL CONSENSUS...SO ACTUALLY TRENDED THE GIVEN ALLBLEND
SOLUTION LOWER TO ONLY INCLUDE SLIGHT CHANCES AT THIS POINT ACROSS
MUCH OF THE REGION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 131 PM EDT FRI JUL 25 2014

LOW CLOUDS CONTINUE TO LIFT AND MIX OUT AND ALL SITES SHOULD RETURN
TO VFR CONDITIONS BY 18Z...OR VERY SHORTLY THEREAFTER. SCATTERED TO
BROKEN MID AND HIGH CLOUDS...DEBRIS FROM A THUNDERSTORM COMPLEX WELL
TO OUR WEST...WILL DRIFT OVERHEAD TONIGHT. THESE CLOUDS ALONG WITH
SOME DRYING OF THE LOW LEVEL AIRMASS ARE EXPECTED TO KEEP A REPEAT
OF THE WIDESPREAD FOG AND LOW CIELINGS FROM DEVELOPING AGAIN TONIGHT.
WILL HOWEVER HIGHLIGHT A BRIEF PERIOD OF MVFR CONDITIONS AT LOZ AND
SME AROUND DAWN ON SATURDAY AS SOME PATCHY VALLEY FOG IS STILL
LIKELY TO FORM.


&&

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

$$

SHORT TERM...ABE
LONG TERM...JMW
AVIATION...ABE




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