Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 291850 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
250 PM EDT TUE JUL 29 2014

.UPDATE...
ISSUED AT 250 PM EDT TUE JUL 29 2014

THE CLOUDS ACROSS THE NORTH HELD TEMPERATURES IN CHECK UP THERE FOR
MUCH OF THE DAY SO FAR. HOWEVER...THEY ARE CLEARING OUT NOW AND
SHOULD ALLOW READINGS TO CATCH UP. EVEN SO...HAVE ADJUSTED HIGHS FOR
THIS AREA DOWN A COUPLE OF DEGREES AND ALSO FINE TUNED THE HOURLY
T/TD GRIDS THROUGH THE REST OF THE AREA PER THE LATEST OBS AND
TRENDS. THESE MINOR CHANGES HAVE BEEN SENT TO THE NDFD AND WEB
SERVERS.

UPDATE ISSUED AT 1055 AM EDT TUE JUL 29 2014

14Z SFC ANALYSIS SHOWS HIGH PRESSURE OVER THE MIDWEST AND OHIO
VALLEY. A NEARBY UPPER LOW IS KEEPING STRATO-CU AROUND AND FROM
THIS...SIMILAR TO YESTERDAY AFTERNOON...A FEW SPRINKLES WILL BE
POSSIBLE. HAVE ADDED THIS TO THE FORECAST AND ALSO ADJUSTED THE SKY
COVER THROUGH THE AFTERNOON. ALSO...FINE TUNED THE T AND TD GRIDS
BASED ON THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE. THESE HAVE
BEEN SENT TO THE NDFD AND WEB SITES ALONG WITH A FRESHENED SET OF
ZONES.

UPDATE ISSUED AT 750 AM EDT TUE JUL 29 2014

FRESHENED UP THE HOURLY TEMPERATURES...DEW POINTS...AND SKY COVER TO
MATCH UP BETTER WITH THE LATEST TREND IN OBSERVATIONS.
OTHERWISE...THE FORECAST REMAINS ON TRACK.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 339 AM EDT TUE JUL 29 2014

BROAD CYCLONIC FLOW WILL REMAIN ENTRENCHED ACROSS THE OHIO AND
TENNESSEE VALLEYS THROUGH THE SHORT TERM...BRINGING UNSEASONABLY COOL
TEMPERATURES TO THE REGION. WEAK SURFACE HIGH PRESSURE WILL BECOME
MORE ESTABLISHED ACROSS EASTERN KENTUCKY THROUGH THE PERIOD...
KEEPING OUR WEATHER MAINLY DRY.

HIGHS TODAY WILL REACH INTO THE LOW AND MID 70S UNDER PARTLY CLOUDY
SKIES. LOWS TONIGHT WILL DROP WELL INTO THE 50S AS SKIES BECOME
MOSTLY CLEAR. CAN NOT RULE OUT A FEW UPPER 40S...WHICH WOULD MOST
LIKELY ECLIPSE RECORD LOWS AT SOME LOCATIONS. TEMPERATURES WILL
REBOUND ON WEDNESDAY AS HEIGHTS RECOVER....RANGING FROM THE UPPER 70S
TO AROUND 80.

.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 339 AM EDT TUE JUL 29 2014

STRONG UPPER LEVEL TROUGHING WILL BE CENTER STAGE THROUGH THE
EXTENDED...BEING BLOCKED BETWEEN TWO STRONG RIDGES...ONE ACROSS THE
SOUTHWEST CONUS...AND ONE OFF THE ATLANTIC SEABOARD. THIS TROUGH
CURRENTLY EXTENDS FROM AN UPPER LEVEL LOW OVER THE HUDSON BAY AND
PULLS SOUTHWARD ALL THE WAY TO THE GULF COAST. SO LONG AS THIS
PATTERN IS IN PLACE...WE WILL EXPERIENCE WELL BELOW NORMAL
TEMPERATURES. EVERY DAY DURING THE EXTENDED PERIOD IS LOOKING AT
UPPER 70S AND LOW 80S FOR HIGHS...AND UPPER 50S TO LOW 60S FOR LOWS.
THERE WILL BE NO DISTINCT SHORTWAVES WHICH WILL TRAVERSE THE PATH OF
THE UPPER LEVEL TROUGH...BUT THE JET STREAM SET UP IN THIS REGIME
WILL HAVE A STRONG INFLUENCE IN THE PRECIP CHANCES FOR THE TIME
PERIOD.

GIVEN THE UNUSUALLY SOUTHWARD PROGRESSION OF THIS POLAR LOW...THE
POLAR JET STREAM WILL ALSO PULL UNCOMMONLY FAR SOUTHWARD /ESPECIALLY
FOR THIS TIME OF YEAR/...ROUNDING THE TROUGH ALONG THE OHIO RIVER
AND TENNESSEE VALLEY REGION. FOR THURSDAY...THIS JET WILL BE WEST TO
EAST ORIENTED ACROSS THE OHIO RIVER VALLEY...PULLING IN DRY NW FLOW.
SOME LOW LEVEL MOISTURE AND SURFACE UPSLOPE FLOW COULD PRODUCE A FEW
ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE HIGHEST TERRAIN IN THE
SE...BUT OTHERWISE PREDOMINATELY DRY WEATHER IS EXPECTED. BY FRIDAY
HOWEVER...THE JET SHIFTS SLIGHTLY WESTWARD SO THAT IT BECOMES MORE
SW TO NE ORIENTED ACROSS EASTERN KY. THIS WILL PULL DEEP MOISTURE IN
THE MID AND UPPER LEVELS ACROSS THE APPALACHIAN AND EASTERN SEABOARD
REGION...AND BRING THE CHANCE FOR DIURNALLY DRIVEN SHOWERS AND
THUNDERSTORMS ACROSS EASTERN KY AND POINTS SOUTH AND EAST DURING THE
AFTERNOON HOURS. THE JET WILL THEN REMAIN IN THIS POSITION THROUGH
THE END OF THE FORECAST PERIOD...WITH SHOWERS AND THUNDERSTORMS
EXPECTED DURING THE AFTERNOON HOURS ACROSS EASTERN KY EACH DAY.
GIVEN THE LACK OF SHORTWAVES MOVING THROUGH THE FLOW OF THE
TROUGH...NO WIDESPREAD PRECIP CHANCES ARE EXPECTED ACROSS THE
REMAINDER OF KY DURING THE EXTENDED FORECAST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 225 PM EDT TUE JUL 29 2014

CIGS...WHERE THEY EXIST...ARE NOW ABOVE MVFR SO THAT HAS SIMPLIFIED
THE TAFS THROUGH THE FIRST PART OF THE NIGHT AS THE CLOUDS CONTINUE
TO TREND TOWARD CLEARING. THE LACK OF SUBSTANTIAL CLOUD COVER TONIGHT
SHOULD YIELD GOOD RADIATIONAL COOLING AND VALLEY FOG FORMATION. FOR
THIS...HAVE ALLOWED SOME MVFR FOG AT JKL AND SJS AND A TIME OF IFR
CONDITIONS AT LOZ AND SME BETWEEN 07 AND 13Z. THE FOG WILL BURN OFF
SHORTLY AFTER DAWN WITH ANY CIGS NEAR 4K FEET. CANNOT RULE OUT A
STRAY SHOWER ACROSS THE NORTH BY MIDDAY WEDNESDAY...BUT THIS WILL NOT
AFFECT ANY TAF SITES. WINDS WILL REMAIN RATHER LIGHT OUT OF THE NORTH
AND NORTHWEST THROUGH THE PERIOD.

&&

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

$$

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






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