Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 022325 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 725 PM EDT SUN AUG 2 2015 .UPDATE... ISSUED AT 712 PM EDT SUN AUG 2 2015 BROAD AREA OF HIGH PRESSURE REMAINS IN CONTROL ACROSS MUCH OF THE OHIO AND TENNESSEE VALLEY INCLUDING EASTERN KY THIS EVENING. THIS IS LEADING TO MOSTLY CLEAR SKIES ACROSS MUCH OF THE REGION WITH A FEW LOCATIONS STILL SEEING SOME FAIR WEATHER CU. RIGHT NOW FORECAST REMAINS ON TRACK WITH SOME MINOR ADJUSTMENTS TO LATEST OBS AND TRENDS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 330 PM EDT SUN AUG 2 2015 AFTERNOON SURFACE ANALYSIS SHOWS A BROAD AREA OF SURFACE HIGH PRESSURE CENTERED ALONG THE KY/WV BORDER. THIS IS ALONG FOR MOSTLY SUNNY TO SUNNY SKIES ACROSS ALL OF EASTERN KY THIS AFTERNOON. THERE ARE A FEW DIURNALLY DRIVEN CU SHOWING UP ON VIS SAT...BUT THESE ARE FAIR WEATHER CU. THIS WILL MAKE FOR A QUIET AND CALM NIGHT ACROSS EASTERN KY WITH THAT WILL ALSO COME THE FOG POTENTIAL OVERNIGHT. THINK THIS WILL BE SIMILAR TO WHAT WE HAVE SEEN THE PAST COUPLE OF NIGHTS WITH MOSTLY RIVER VALLEYS AND LOCATIONS CLOSER TO LARGER BODIES OF WATER SEEING THE BETTER FOG POTENTIAL. THEREFORE ADJUSTED FORECAST GRIDS IN THAT DIRECTION. THIS HIGH WILL GENERALLY SHIFT EAST OVERNIGHT INTO EARLY MONDAY. NOW FOR MONDAY WE ARE CONTINUING TO WATCH A COLD FRONT TO THE NW THAT WILL EVENTUALLY WORK SOUTH AND EAST INTO THE REGION IN THE LATER HALF OF THE PERIOD. ONGOING CONVECTION ACROSS OHIO WILL LIKELY DISSIPATE AS IT MOVES SOUTH AND EAST. THEREFORE STILL THINK MUCH OF THE MORNING INTO THE EARLY AFTERNOON WILL REMAIN DRY ON MONDAY. OVERALL SETUP WE HAVE THE AFOREMENTIONED COLD FRONT...WHILE THE ATTENDANT LOW PRESSURE WILL BE LOCATED WELL NORTHEAST ACROSS NORTHERN QUEBEC. THE 500MB LOW WILL BE LOCATED JUST TO THE EAST OF THE LOW PRESSURE CENTER IN CANADA. WHILE SOME SPOKES OF ENERGY WILL ROLE THROUGH THE LARGER CLOSED LOW THESE WILL BE MORE PRONOUNCED ACROSS THE MID ATLANTIC. THEREFORE WE WILL BE ON THE FAR SOUTHERN EXTENT OF THE BETTER LIFTING FOR ASCENT. HOWEVER CANNOT DENY THE BOUNDARY BEING IN AND NEAR TO THE REGION PROVIDING SOME AMOUNT OF LIFT. THAT SAID WE WILL STILL SEE INCREASED SW FLOW IN RESPONSE THE FRONT MOVING SOUTHEAST INTO THE REGION...THEREFORE WARM AND MOIST AIR WILL CREEP BACK IN GIVING WAY TO A REASONABLY UNSTABLE ENVIRONMENT ACROSS PORTIONS OF EASTERN KY. LOOKING AT FORECAST SOUNDINGS THERE IS ALSO REASONABLY AMOUNT OF DRY MID LEVEL AIR AND STEEP 0-3 KM LAPSE RATES NEAR AND ABOVE 8.0 C/KM IN THE AFTERNOON PARTICULARLY ALONG AND NORTH OF THE I64 CORRIDOR. THIS IS LEADING TO DCAPE VALUES NEAR AND ABOVE 1000 J/KG...SO ANY STORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL FOR STRONG GUSTY WINDS DUE TO MOMENTUM TRANSFER. RIGHT NOW NOT SOLD ON ANY SEVERE HAIL POTENTIAL GIVEN HIGHER FREEZING LEVELS AND WARM TEMPS IN PLACE. THE WIND THREAT SEEMS MOST LIKELY GIVEN BOTH CLIMATOLOGY AND OVERALL CIPS ANALOGS. THE FACT THAT THE BETTER LIFT AND SUPPORT WILL BE NORTHEAST OF THE REGION SPC HAS TRANSLATED THE SLIGHT RISK NORTHEAST OUT OF EASTERN KY...BUT AREAS GENERALLY ALONG AND NORTH OF THE MOUNTAIN PARKWAY REMAIN IN A MARGINAL RISK MONDAY. THEN THUNDERSTORMS ARE EXPECTED TO DECREASE IN INTENSITY AND COVERAGE AS WE MOVE INTO THE NIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 444 PM EDT SUN AUG 2 2015 MODELS SHOW A STALLED FRONTAL BOUNDARY NEAR THE SOUTHERN PORTION OF THE JKL FORECAST AREA AS THE PERIOD STARTS. IT WILL BEGIN TO LIFT NORTH TUESDAY THROUGH WEDNESDAY. WARM AIR ADVECTION AND GENERAL CONVERGENCE IN THE VICINITY OF THE FRONT COULD LEAD TO SHOWERS/THUNDERSTORMS...BUT TRYING TO TIME THEM AT THIS STAGE WOULD BE FRUITLESS. THE HIGHEST PROBABILITY OF RAIN APPEARS TO BE FROM WEDNESDAY NIGHT THROUGH THURSDAY...OR POSSIBLY THURSDAY NIGHT. DURING THIS TIME...MODELS SHOW MORE SIGNIFICANT UPPER LEVEL SUPPORT AS WAVES MOVING THROUGH AN EASTERN CONUS TROUGH CAUSE THE TROUGH TO AMPLIFY OVER OUR AREA. MODELS AGREE ON THE GENERAL SCENARIO... BUT NOT THE DETAILS OF THE IMPULSES TRAVELING THROUGH. RAIN WOULD APPEAR TO BE A GOOD BET DURING THIS TIME FRAME...BUT THE CONFIDENCE IN ANY GIVEN 12 HOUR BLOCK IS NOT TERRIBLY HIGH. PEAK 12 HOUR POPS IN THE 50-60 PERCENT RANGE ARE BEING USED AT THIS POINT...BUT THIS WILL PROBABLY INCREASE AT A LATER TIME. A COLD FRONT LOOKS POISED TO MOVE THROUGH THURSDAY NIGHT AND ALLOW A DRIER AIR MASS TO TRY TO MOVE IN. HOWEVER... MODELS HAVE SHOWN SOME INCONSISTENCY CONCERNING HOW LONG THE UPPER TROUGH HANGS OVER THE AREA AT THE END OF THE WEEK. HAVE HELD ONTO SLIGHT CHANCE POPS THROUGH THE WEEKEND UNTIL THE SCENARIO BECOMES MORE CLEAR. && .AVIATION...
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(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 725 PM EDT SUN AUG 2 2015 BROAD AREA OF HIGH PRESSURE REMAINS IN CONTROL OF TAF SITES THROUGH TONIGHT. THE CAVEAT OF COURSE TO THAT IS THE POSSIBILITY OF FOG OVERNIGHT INTO THE DAWN HOURS MONDAY. THEREFORE LEANED TOWARD GUIDANCE AND PERSISTENCE OVERNIGHT BRINGING IFR VIS INTO SME AND MVFR VIS INTO SYM/SJS. OTHER SITES LOOK TO BE OKAY WITH BEST FOG PRODUCTION ACROSS RIVER VALLEYS AND NEAR LARGER BODIES OF WATER. THIS WILL LIFT BY AROUND 12Z AT TAF SITES...THEN ALL SITES LOOK TO HOLD VFR THROUGH THE REST OF THE TAF PERIOD. THE NEXT WEATHER MAKER MAKES IT/S APPEARANCE LATE IN THE PERIOD AND GIVEN THE FACT THAT IT WILL BE MOVING IN THE THE NW OPTED TO ADD VCTS BY 21Z AT SYM. OVERALL EXPECTING WINDS TO REMAIN LIGHT THROUGH THE TAF PERIOD AT ALL THE TAF SITES...HOWEVER MONDAY AFTERNOON WE COULD SEE SOME GUSTS OF 10 TO 15 KTS OUT OF THE WSW AHEAD OF THE FRONT IN THE FAR NORTH.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...DJ LONG TERM...HAL AVIATION...DJ

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