Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 201215 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
815 AM EDT WED AUG 20 2014

.UPDATE...
ISSUED AT 800 AM EDT WED AUG 20 2014

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL EXIT SOUTHEASTERN
KENTUCKY IN THE NEXT ONE TO TWO HOURS. ONCE THESE STORMS CLEAR THE
AREA...THERE MAY BE SOME ISOLATED TO SCATTERED CONVECTION RE-
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON DURING PEAK
HEATING. WILL STAY THE COURSE AND CONTINUE TO MENTION THE
POPS...HOWEVER SOME OF THE GUIDANCE HAS TRENDED DRIER...AND GIVEN THE
SUBSIDENCE FOLLOWING THE DEPARTING WAVE...WOULD NOT BE SURPRISED IF
CONVECTION IS EVEN MORE ISOLATED. UPDATES HAVE BEEN SENT.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 357 AM EDT WED AUG 20 2014

A COMPLEX OF SHOWERS AND THUNDERSTORMS IS CURRENTLY SLIDING EAST
ACROSS THE OHIO VALLEY ASSOCIATED WITH A PASSING SHORT WAVE TROUGH.
THE MORE ORGANIZED PORTION OF THIS COMPLEX HAS BEEN CONFINED TO ALONG
AND NORTH OF THE MOUNTAIN PARKWAY. THE HRRR MODEL HAS NOT BEEN
HANDLING THIS FEATURE WELL THROUGH THE OVERNIGHT...OVERPLAYING THE
DEVELOPMENT TO THE SOUTH THAT HAS BEEN WEAK IN REALITY...WHILE
UNDERPLAYING WHERE CONVECTION HAS BEEN MORE ORGANIZED AND SUSTAINED.

EXPECT THIS COMPLEX TO KEEP MOVING EAST...AFFECTING LOCATIONS ALONG
AND NORTH OF THE MOUNTAIN PARKWAY FOR THE NEXT FEW HOURS...BEFORE
EXITING THE AREA BY 12Z. THERE WILL BE SOME SUBSIDENCE FOLLOWING THIS
DEPARTING SHORT WAVE FOR TODAY WORKING IN FROM WEST TO EAST...SO HAVE
TRIMMED THE POPS BACK A BIT...PEAKING IN THE 20 TO 30 RANGE FOR MOST
LOCATIONS DURING THE HOTTER PART OF THE DAY. HIGHS TODAY WILL RANGE
FROM 85 TO 90 DEGREES.

AS WE HEAD INTO TONIGHT...CONVECTION WILL BE ON THE DOWNWARD TREND
THROUGH 06Z...BUT THEN LOOKS TO INCREASE BETWEEN 06 AND 12Z...AS
ANOTHER SHORT WAVE TROUGH APPROACHES FROM THE NORTHWEST. POP CHANCES
WILL CONTINUE TO INCREASE THROUGH THE DAY ON THURSDAY WITH HEATING
AIDING THE MODEST FORCING FROM THE PASSING SHORT WAVE. HAVE MAINTAINED
THE BETTER POPS IN THE NORTHEAST...AND LESSER VALUES IN THE
SOUTHWEST...FURTHER REMOVED FROM THE BETTER FORCING. HIGHS WILL
RETURN TO THE 85 TO 90 DEGREE RANGE IN THE SOUTHWEST...WITH MID 80S
IN THE NORTHEAST...WHERE MORE PERSISTENT CLOUD COVER WILL RESIDE.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 AM EDT WED AUG 20 2014

THE EXTENDED PORTION OF THE FORECAST BEGINS ON THURSDAY NIGHT WITH A
SLOWLY BUILDING RIDGE OVER THE CENTRAL CONUS AND DIGGING TROUGHS
OVER THE NORTHWEST AND NORTHEAST. THIS GENERAL TREND CONTINUES
THROUGH THE ENTIRE EXTENDED PERIOD. DURING THIS PERIOD...QUITE A FEW
STRONG SHORTWAVES TRAVEL OVER THE BUILDING RIDGE IN THE CENTRAL
PLAINS AND INTO THE OH VALLEY AND GREAT LAKES REGION. THE FIRST WAVE
OF NOTE WILL BE THE SHORTWAVE MOVING THROUGH AT THE BEGINNING OF THE
EXTENDED. AFTER THIS...THE PATTERN TURNS INTO A MORE MCS DRIVEN
PATTERN FRIDAY THROUGH SUNDAY WITH ACTIVITY CENTERED AROUND WHAT THE
DAYS CONVECTION BRINGS AND IS DIURNALLY AFFECTED. THROUGH THE PERIOD
THE UPPER RIDGE SLOWLY WEAKENS AND DRIFTS EAST.

CONCERNING THE MODELS DURING THE EXTENDED...THE GFS AND EURO LOOK TO
BE RIGHT ON TRACK AND IN GOOD AGREEMENT. THOUGH...THE EURO LOOKS TO
CUT OFF ANY CONVECTION BY THE END OF THE EXTENDED AS THE RIDGE AXIS
SETS UP RIGHT OVER EASTERN KENTUCKY LEADING TO AN END TO ALL
DIURNALLY DRIVEN CONVECTION AND DISPLACING THE TRACK OF THE MCS MORE
TO THE NORTHEAST. BASED ON THE GOOD AGREEMENT...IT SEEMS TO BE A
GOOD CONSENSUS TO STAY CLOSE TO THE SOLUTION OF THE ALL BLEND MODEL.
THOUGH DEPENDING ON WHAT THE 00Z EURO DOES ON THE MONDAY AND TUESDAY
TIME FRAME FOR THE RIDGE AXIS RIGHT OVER THE AREA...MAY DROP POPS
BELOW THE ALL MODEL BLEND SOLUTION. WITH THE SOLUTION OF THE ALL
MODEL BLEND...THE BEST CHANCE OF POPS WILL BE DURING THE FRIDAY
THROUGH SUNDAY TIME FRAME AND LESS DURING THE MONDAY AND TUESDAY
TIME FRAME WHERE THE RIDGE WILL BE OVER EASTERN KENTUCKY AND HAVE
LEFT SLIGHT CHANCE MAINLY DURING THE AFTERNOON ON MONDAY AND
TUESDAY.

IN ADDITION TO THIS PATTERN...TEMPERATURES WILL BE ON THE INCREASE
IN EARNEST AS SOME OF THE WARMEST WEATHER OF THE ENTIRE SUMMER WILL
BEGIN TO SET IN FROM FRIDAY THROUGH THE REST OF THE EXTENDED. HIGH
TEMPERATURES WILL SURPASS 90 DEGREES IN SOME AREAS OF EASTERN
KENTUCKY AND HUMIDITY WILL BE ON THE INCREASE AS WELL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 815 AM EDT WED AUG 20 2014

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL EXIT OFF TO THE
SOUTHEAST IN THE NEXT HOUR OR TWO. IFR/LIFR FOG WILL LIFT OUT IN THE NEXT
HOUR...WITH A RETURN TO VFR CONDITIONS THROUGH THE REST OF THE DAY.
SOME ISOLATED TO SCATTERED CONVECTION WILL THREATEN AGAIN THIS
AFTERNOON...BUT COVERAGE IS EXPECTED TO BE LIMITED ENOUGH TO ONLY
MENTION VCTS FOR NOW. FOG WILL LIKELY RETURN AFTER 06Z TONIGHT...HOWEVER
ANOTHER UPPER LEVEL DISTURBANCE WILL LIKELY APPROACH BETWEEN 06 AND
12Z...BRINGING IN ADDITIONAL CLOUD COVER AND ALSO RENEWING THE
CONVECTIVE THREAT. THIS WILL LIKELY KEEP THE FOG FROM BECOMING TOO
DENSE.

&&

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

$$

UPDATE...GEOGERIAN
SHORT TERM...GEOGERIAN
LONG TERM...SHALLENBERGER
AVIATION...GEOGERIAN





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