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000
FXUS63 KJKL 171732
AFDJKL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
132 PM EDT MON JUN 17 2013

.UPDATE...
ISSUED AT 1152 AM EDT MON JUN 17 2013

UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE STORMS IN CENTRAL KENTUCKY THAT WERE MOVING INTO EASTERN
KENTUCKY HAVE RECENTLY DECREASED IN INTENSITY AND BUILT FURTHER TO
THE SOUTH AND ARE ONCE AGAIN INCREASING IN INTENSITY OF THE LINCOLN-
CASEY COUNTY BORDER. EXPECT THESE STORM TO CONTINUE BUILDING AND
PRODUCE THUNDER AGAIN AS THEY MOVE INTO PULASKI/ROCKCASTLE COUNTIES.
ALSO CONVECTION IS ALREADY SPRINGING UP NEAR CUMBERLAND. TODAY SHOULD
BE MUCH LIKE YESTERDAY WITH POP UP THUNDERSTORMS FORMING. TODAY IS
ACTUALLY A BIT MORE UNSTABLE THAN YESTERDAY AND THERE IS SOME DRY AIR
ALOFT. AS SUCH...THERE IS A BETTER CHANCE TO SEE A SEVERE
THUNDERSTORMS OR TWO THIS AFTERNOON AND EARLY EVENING WITH STRONG
WINDS BEING THE BIGGEST THREAT.

UPDATE ISSUED AT 720 AM EDT MON JUN 17 2013

A FEW SHOWERS HAVE POPPED UP ACROSS CENTRAL KY...AS WELL AS ONE JUST
EAST OF LONDON. FORECASTED POPS SEEMED TO JIVE WELL WITH THIS
ISO/SCT SHOWER DEVELOPMENT OVER THE CWA...WITH THE BETTER POTENTIAL
OVER THE SOUTHERN HALF...INCREASING THIS AFTERNOON UNDER BEST
INSTABILITY. ONLY UPDATE WAS TO INCLUDE LATEST OBSERVATIONS WITHIN
THE FORECAST GRIDS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 530 AM EDT MON JUN 17 2013

.SHORT TERM...

500MB SHORTWAVE OVER THE SOUTHERN PLAINS SPAWNED A LARGE AREA OF
CONVECTION OVERNIGHT LAST NIGHT...AND WILL CONTINUE TO DIVE SSE
ALONG THE ZONAL FLOW TONIGHT/TUESDAY MORNING. AS THIS AREA OF
CONVECTION EXPANDED THROUGHOUT THE NIGHT...CLOUD COVER BEGAN TO
DEVELOP AND EXPAND ACROSS MUCH OF KENTUCKY IN RESPONSE TO AN INFLUX
OF MOISTURE AHEAD OF THE SYSTEM. UNFORTUNATELY...THIS CUT OFF BEST
FOG POTENTIAL AS WAS EXPECTED WITH EVENING UPDATE. MORNING FORECAST
HAS A REDUCTION IN THE IMPACTS OF FOG ACROSS THE REGION...WITH
PATCHY TO AREAS STILL POSSIBLE ACROSS MUCH OF THE VALLEYS.

OTHERWISE...MAIN FOCUS TURNS TO CONVECTION AS THE SHORTWAVE NEARS
THE AREA TUESDAY. AS IT APPROACHES...A WEAK SURFACE FRONT WILL
REMAIN STATIONARY JUST NORTH OF THE REGION. WINDS REMAIN S/SW ACROSS
KY AHEAD OF THIS FRONT...MAKING A SHARP VEERING PATTERN IN THE MID
LEVELS BY EARLY AFTERNOON. IN ADDITION TO LAPSE RATES OVER THE AREA
IN THE 6.5C RANGE...LATEST NAM FORECAST SOUNDINGS SUPPORT POTENTIAL
FOR SOME STRONG CONVECTIVE DEVELOPMENT. MOISTURE IN THE LOW/MID
LEVELS AND DRY ALOFT...DAYTIME HEATING WILL MAKE IT EASY TO TAP INTO
A VERY DECENT POOL OF INSTABILITY /CAPE VALUES AROUND 2800 J/KG BY
18Z/. WITH SUCH AN ENVIRONMENT IN PLACE...EXPECT INDIVIDUAL CELLS TO
DEVELOP ACROSS THE CWA RATHER THAN A WIDESPREAD AREA OF PRECIP.
UNTIL CELLS DEVELOP...EXACT COVERAGE/TIMING/LOCATION IS STILL
UNCERTAIN...SO TRIED NOT TO GO LIKELY AT THIS TIME.

ACTUAL SHORTWAVE AND BEST PRECIP WILL THEN BEGIN TO AFFECT THE JKL
CWA BY EARLY TUESDAY MORNING. BEST MOISTURE WILL SLIDE TO OUR
SOUTH...BUT STILL EXPECT A FAIRLY WIDESPREAD SWATH OF RAIN AND
EMBEDDED THUNDERSTORMS TO SPREAD ACROSS PORTIONS OF THE CWA.
FORECAST SOUNDINGS ARE MUCH MORE SATURATED BY 15Z TUESDAY...AND
THOUGH INSTABILITY IS PRESENT...CONDITIONS DON/T LOOK QUITE AS
FAVORABLE AS TODAY. SOUNDINGS THEN SHOW A GOOD INFLUX OF DRY AIR BY
WED 0Z AS SHORTWAVE CONTINUES OFF TO THE SE AND HIGH PRESSURE
FINALLY BEGINS TO TAKE HOLD.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 530 AM EDT MON JUN 17 2013

.LONG TERM...TUESDAY THROUGH SUNDAY

THE PATTERN LOOKS RATHER MURKY...WITH SYSTEMS THAT ARE NOT WELL
DEFINED AT THE START OF THE PERIOD. A BROAD UPPER TROUGH SHOULD BE
OVER THE EASTERN CONUS...WITH A WEAK COLD FRONT SINKING SOUTH
THROUGH THE OHIO VALLEY. ONGOING CONVECTION FROM THE DAY MAY LINGER
INTO THE NIGHT...BUT SHOULD DIMINISH AS HEATING IS LOST AND SLIGHTLY
COOLER/DRIER AIR BEGINS TO ARRIVE FROM THE NORTH. THE CHANGE IN AIR
MASS SHOULD PREVENT DEEP CONVECTION ON WEDNESDAY...WITH WARMING MID
LEVEL TEMPS ADDING TO THE SUPPRESSION ON THURSDAY.

OUR LOW LEVEL FLOW IS EXPECTED TO TURN BACK TOWARD THE SOUTH FRIDAY
THROUGH THE WEEKEND...BRINGING AN INCREASE IN MOISTURE. HOWEVER...AT
THE SAME TIME THE EASTERN CONUS TROUGH WILL BE GETTING REPLACED BY
RIDGING BUILDING EAST FROM THE CENTRAL CONUS. FORECAST SOUNDINGS DO
NOT LOOK PARTICULARLY FAVORABLE FOR DEEP CONVECTION. HOWEVER...MID
LEVEL TEMPS ARE SHOWN TO BE SLIGHTLY COOLER OVER OUR SOUTHEAST
COUNTIES. COMBINED WITH THE DIFFERENTIAL HEATING OF HIGHER TERRAIN
THERE...IT IS ENOUGH TO WARRANT SLIGHT CHANCE POPS FRIDAY THROUGH
SUNDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 132 PM EDT MON JUN 17 2013

FORECAST SOUNDINGS LOOK SUPPORTIVE FOR CONTINUED CONVECTIVE
DEVELOPMENT THROUGHOUT THE AFTERNOON AND EVENING. THE ATMOSPHERE IS
UNSTABLE TODAY AND THERE IS SOME DRY AIR IN THE MID LAYERS. THIS IS
CONDUCIVE FOR SOME STRONG DOWNDRAFTS. DOWNDRAFTS MAY ALSO BE WELL
AHEAD OF THE CONVECTION SO EXTRA CAUTION SHOULD BE EXERCISED TODAY EVEN
WITH THE STORMS BEING A FEW MILES AWAY. DEPENDING ON HOW MUCH RAIN
THERE IS TODAY...THERE SHOULD BE SOME FOG/MIST FORMING IN THE
MORNING. THE FORECAST PRESUPPOSES THERE WILL BE AMPLE RAINFALL
TONIGHT. IF THE RAIN DOES NOT OCCUR...THEN THE FOG WILL NOT BE AS BAD
AS IN THE FORECAST.

&&

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

$$

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