Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 271759 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON KY
159 PM EDT WED AUG 27 2014

.UPDATE...
ISSUED AT 159 PM EDT WED AUG 27 2014

FRESHENED UP THE HOURLY TEMPERATURES AND DEW POINTS TO ACCOUNT FOR
THE LATEST TRENDS IN OBSERVATIONS...OTHERWISE THE FORECAST REMAINS
ON TRACK.

UPDATE ISSUED AT 1125 AM EDT WED AUG 27 2014

THE FORECAST REMAINS ON TRACK TODAY. DID MAKE SOME MINOR ADJUSTMENTS
TO THE POP TIMING THIS AFTERNOON BASED ON THE LATEST TRENDS IN THE
HRRR...WHICH IS STILL SHOWING SOME ISOLATED CONVECTION POPPING ACROSS
LOCATIONS GENERALLY NORTH OF THE MOUNTAIN PARKWAY ASSOCIATED WITH AN
APPROACHING WEAK COLD FRONT.

UPDATE ISSUED AT 728 AM EDT WED AUG 27 2014

UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE COLD FRONT IS SLOWLY MOVING TOWARD THE AREA. EXPECT SOME
ISOLATED SHOWERS AND THUNDERSTORMS NORTH OF THE MOUNTAIN PARKWAY THIS
AFTERNOON. THE FRONT STILL LOOKS LIKE IT WILL BE WEAKENING AS IT
MOVES INTO THE AREA.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 227 AM EDT WED AUG 27 2014

HIGH PRESSURE IS IN PLACE OVER EASTERN KENTUCKY AT BOTH THE SURFACE
AND ALOFT. A COLD FRONT WILL BE MOVING SOUTH DURING THE DAY TODAY.
THE FRONT WILL BE WEAKENING AS IT BUMPS UP AGAINST THE SURFACE AND
UPPER HIGHS. CURRENT THINKING IS THAT THERE WILL BE SOME
PRECIPITATION NORTH OF THE MOUNTAIN PARKWAY THIS AFTERNOON...HOWEVER
AS THE FRONT CONTINUES TO WEAKEN TONIGHT AS IT MOVES SOUTH...THE
PRECIPITATION WILL BE ENDING. ON THURSDAY...AS THE DIURNAL HEATING
GETS GOING...IT WILL GENERATE SOME SHOWERS AND THUNDERSTORMS ALONG
THE REMNANTS OF THE FRONT...GENERALLY SOUTH OF THE MOUNTAIN PARKWAY
DURING THE AFTERNOON AND EVENING. THE TEMPERATURES WILL CONTINUE IN
THE MID TO UPPER 80S TODAY AND THEN COOL OFF A LITTLE WITH THE FRONT
TOMORROW. THE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THIS SYSTEM
SO CONFIDENCE IS BETTER THAN AVERAGE.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 315 AM EDT WED AUG 27 2014

UPPER LEVEL RIDGING OVER THE FAR SE CONUS WILL CONTINUE TO SHIFT
EASTWARD FRIDAY AND INTO SATURDAY. MEANWHILE...ANOTHER HIGH PRESSURE
RIDGE SITTING OVER THE FAR SW CONUS WILL BUILD STRENGTH. THESE TWO
SYSTEMS WILL IN TURN CREATE A TROUGHING PATTERN ACROSS THE CENTRAL
US. MODELS ARE STILL ON TRACK FOR THIS TROUGH TO DEVELOP INTO A
CLOSED UPPER LEVEL LOW BY THE START OF THE FORECAST PERIOD AT 0Z
FRIDAY...AND SLOWLY PUSH EASTWARD BEHIND THE EXITING SE HIGH. THIS
WILL RESULTING IN FALLING HEIGHTS ACROSS EASTERN KY AND THE RETURN
OF MORE UNSETTLED WEATHER THROUGH THE WEEKEND. A STRONG QUASI
STATIONARY FRONT WILL BE PRESENT AT THE SURFACE...FROM MN/WI
SOUTHWARD INTO TX. MEANWHILE...A SURFACE WARM FRONT WILL PUSH
NORTHWARD BACK ACROSS KY DURING THE DAY FRIDAY...WITH SOUTHERLY FLOW
EXPECTED TO USHER IN WARM MOIST AND UNSTABLE AIR FRIDAY AFTERNOON
AND THROUGH THE DAY SATURDAY.

THE COLD FRONT WILL FINALLY SHIFT BY SATURDAY AFTERNOON. UP UNTIL
THIS POINT...THE BEST PRECIP POTENTIAL WILL REMAIN TO THE WEST OF
OUR CWA...BUT THE COMBINATION OF THE AFTERNOON HEATING/INSTABILITY
AND THE INCOMING BOUNDARY WILL BEGIN TO PUSH CONVECTIVE POTENTIAL
INTO THE REGION. THE BOUNDARY WILL LIKELY NOT ACTUALLY MAKE IT INTO
THE OHIO RIVER VALLEY HOWEVER. INSTEAD...THE SURFACE LOW TO OUR
NORTH WILL RACE EASTWARD...ELONGATING THE FRONT TO A MORE EAST/WEST
ORIENTATION SATURDAY EVENING. MEANWHILE...UPPER LEVEL FORCING WILL
BEGIN TO DETERIORATE AS THE TROUGHING PATTERN WEAKENS AND BECOMES
MORE ZONAL IN NATURE. UPPER LEVEL RIDGING WILL BEGIN TO BUILD BACK
INTO EASTERN KY INSTEAD. AND BUILDING HEIGHTS AT THE SURFACE AS WELL
WILL KEEP THE FRONTAL BOUNDARY WELL NORTH OF THE OHIO RIVER SHIFTING
TO A MORE NORTHERLY TRACK.

THE EXITING FRONT WILL NOT...HOWEVER...RESULT IN CLEARING
CONDITIONS. IF ANYTHING...IT WILL INCREASE RAIN POTENTIAL...WHILE
SIMULTANEOUSLY DECREASING THE SEVERE THREAT. KY WILL NOW FIND ITSELF
ON THE SOUTHERN EXTENT/WARM SIDE OF THE FRONT SATURDAY AFTERNOON
THROUGH MONDAY. THIS WILL CONTINUE TO PULL WARM MOIST AIR INTO
KY...BUT SHOULD KEEP SOME OF THE BEST INSTABILITY/FRONTAL
CONVERGENCE TO OUR NORTH. AS SUCH...STILL LOOKING AT PWAT VALUES
REACHING AROUND THE 2.0 INCH MARK WITH THE POTENTIAL FOR SOME HEAVY
RAIN SHOWERS SUNDAY INTO MONDAY. DESPITE THE LACK OF BEST
INSTABILITY...THUNDER COULD STILL DEVELOP IN ANY OF THE HEAVIEST
SHOWERS AND PRODUCE DECENT AMOUNTS OF LIGHTNING...AND EVEN SOME
GUSTY WINDS. UNLIKE THE PREVIOUS TORRENTIAL RAINFALLS EXPERIENCED
OVER THE LAST COUPLE OF WEEKS...STORM MOTION IS MUCH MORE
PROGRESSIVE /AROUND 15 KTS/...SO TRAINING OF STORMS AND NEARLY
STATIONARY STORMS WILL BE LESS OF A CONCERN/THREAT.

DRY AIR SHOULD FINALLY WORK IT/S WAY IN FROM ALOFT BY MONDAY NIGHT
AND CUT OFF BEST PRECIP CHANCES. HOWEVER...DIURNALLY DRIVEN SHOWERS
AND THUNDERSTORMS WILL LIKELY RETURN UNDER SOUTHERLY FLOW BY TUESDAY
AFTERNOON...WITH A SIMILAR SET UP EXPECTED FOR TUESDAY NIGHT INTO
WEDNESDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED
AT 159 PM EDT WED AUG 27 2014

AN APPROACHING WEAK COLD FRONT WILL BRING THE THREAT OF ISOLATED
CONVECTION TO LOCATIONS GENERALLY NORTH OF THE MOUNTAIN PARKWAY
THROUGH THIS EVENING. EXPECT SOME IFR OR WORSE FOG TO DEVELOP ONCE
AGAIN IN THE DEEPER RIVER VALLEYS BETWEEN 06 AND 12Z. HAVE
INTRODUCED A SMALL WINDOW OF MVFR FOG AT LOZ AND SME WITH SLIGHTLY
BETTER LOW LEVEL MOISTURE TO WORK WITH HEADING INTO THE OVERNIGHT.
FOG WILL BURN OFF BY AROUND 13Z...WITH VFR CONDITIONS RETURNING.
WINDS WILL REMAIN LIGHT AND VARIABLE THROUGH THE PERIOD AS WELL.

&&

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

$$

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





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