Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 211955 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 355 PM EDT THU AUG 21 2014 .SHORT TERM...
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(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 355 PM EDT THU AUG 21 2014 19Z SFC ANALYSIS SHOWS A SEASONALLY STRONG AREA OF LOW PRESSURE OVER THE HIGH PLAINS WITH HIGH PRESSURE OVER THE DEEP SOUTH. THIS NEARBY HIGH IS NOT ENOUGH TO PREVENT THE LATEST INCARNATION OF MCS ACTIVITY FROM DIVING THROUGH EASTERN KENTUCKY. THIS IS TAKING ADVANTAGE OF HIGH INSTABILITY THROUGHOUT THE AREA GIVEN TEMPERATURES IN THE UPPER 80S AND DEWPOINTS IN THE LOWER 70S. IN ADDITION TO THE SEVERE THUNDERSTORM THREAT...HIGH PWS...LOW FFG...AND A POTENTIAL FOR TRAINING WILL KEEP FLASH FLOODING A CONCERN THROUGH THE EVENING. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST WITH A LARGE AREA OF RIDGING STRETCHING FROM THE LOWER MISSISSIPPI VALLEY INTO THE TENNESSEE VALLEY. AS IT DOES SO...A DEEP LOW TO THE NORTHEAST WILL SEND PACKETS OF ENERGY THROUGH THE OHIO VALLEY AND INTO THE CENTRAL APPALACHIANS IN FAIRLY FAST NORTHWEST FLOW. THIS WILL PLACE AT LEAST NORTHEAST PARTS OF THE JKL CWA IN THE STORM TRACK AND AS PRIME REAL ESTATE FOR MCS ACTIVITY. GIVEN THE MODEL AGREEMENT HAVE FAVORED A BLEND WITH EXTRA EMPHASIS ON THE HRRR AND NAM12 FOR THE FIRST 12 TO 24 HOURS. SENSIBLE WEATHER WILL FEATURE ON GOING THUNDERSTORM ACTIVITY DIMINISHING INTO THE EVENING...BUT PROGRESSING SOUTH WITH THE FAVORED INSTABILITY. LATER TONIGHT...PARTLY CLOUDS SKIES AND THE MOISTURE FROM THE RAIN OF THIS AFTERNOON AND EVENING WILL LIKELY LEAD TO AREAS OF FOG...LOCALLY DENSE. INDICATIONS ARE THAT THE NEXT ROUND OF STORMS STAY TO THE NORTHEAST OF THE CWA TONIGHT. AFTER THE FOG BURNS OFF ON FRIDAY MORNING THE INSTABILITY WILL BUILD AGAIN WITH ANOTHER VERY HUMID AND WARM DAY. THIS WILL BE A SIMILAR SETUP FOR SEVERE AND EXCESSIVE RAIN POTENTIAL...MAINLY IN THE NORTHEAST BASED ON THE EXPECTATION OF EARLY STORMS TRACKING JUST OUTSIDE OF THE CWA AND DEVELOPMENT ON THEIR SOUTHWEST FLANKS. LIKEWISE...PATCHY FOG WILL BE AN ISSUE FOR THE AREA LATER FRIDAY NIGHT GIVEN A SIMILAR SETUP... BUT STILL DEPENDENT ON THE RAINS EARLY IN THE DAY AND EVENING. USED THE CONSSHORT AS A STARTING POINT FOR THE T...TD...AND WINDS THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND FRIDAY NIGHT. AS FOR POPS...ENDED UP HIGHER THAN GUIDANCE...EXCEPT FOR THE MET NORTH OF JKL ON FRIDAY NIGHT...THROUGH SATURDAY MORNING OWING TO THE TENDENCY FOR STORMS TO EXPAND SOUTHWEST OF THEIR DEPICTIONS IN THE MODELS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 315 PM EDT THU AUG 21 2014 STRONG RIDGING WILL LIKELY HOLD OVER THE AREA FOR THE BALANCE OF THE EXTENDED PART OF THE FORECAST. SHOWER AND THUNDERSTORM CHANCES WILL CONTINUE EACH DAY THROUGH THE MIDDLE OF NEXT WEEK. IN ADDITION...WARM AND MUGGY CONDITIONS WILL REMAIN ANCHORED BENEATH THE RIDGE. BEST TIME FOR SHOWERS AND STORMS WILL CONTINUE TO BE EACH AFTERNOON/EVENING...BUT CANNOT RULE OUT AN ISOLATED SHOWER OR STORM AT ANY TIME INTO NEXT WEEK. GFS MOS IS LIKELY A BIT TOO HIGH AND WILL CONTINUE TO GO BETWEEN GFS AND MET MOS THROUGH SATURDAY. ECMWF SEEMS TO BE A GOOD COMPROMISE WITH REGARDS TO TEMPERATURES.
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&& .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 210 PM EDT THU AUG 21 2014 THE AVIATION FORECAST WILL BE A CHALLENGE WITH THE TIMING OF MCS CLUSTERS AND POTENTIAL FOR FOG FORMATION THROUGH THE PERIOD. EXPECT THE BETTER CHANCES FOR LOWER CIGS AND VIS ASSOCIATED WITH STORMS WILL BE FOR THE NORTHERN TAF SITES THROUGH EARLY EVENING. THESE LOCATIONS MAY HAVE A BETTER CHANCE FOR MORE IN THE WAY OF LOWER VIS PRODUCING FOG. HOWEVER...THAT WILL BE DEPENDENT ON ADDED MOISTURE FROM CONVECTION DURING THE REST OF THE DAY AND SOME CLEARING LATER TONIGHT. FOR NOW...HAVE BROUGHT ALL THE SITES TO MVFR IN BR AFTER 06Z AND CLEARING OUT...BACK TO VFR BY 14Z FRIDAY. CANNOT RULE OUT ADDITIONAL STORMS FRIDAY AFTERNOON...ESPECIALLY NORTHEAST...BUT THROUGH 18Z THE TAF SITES SHOULD REMAIN CALM. WINDS THROUGH THE NIGHT WILL BE LIGHT AND VARIABLE...FAVORING THE SOUTHWEST AT 5 TO 10 KTS DURING THE DAYLIGHT HOURS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...KAS AVIATION...GREIF

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