703 FXUS63 KJKL 190820 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 420 AM EDT TUE MAR 19 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 334 AM EDT TUE MAR 19 2013 CONDITIONS ACROSS EASTERN KENTUCKY FEATURE LEFTOVER CLOUD COVER FINALLY EXITING EASTERN KENTUCKY. A FEW AREAS OF SPOTTY DRIZZLE MAY BE PRESENT IN THE EAST BUT THAT WILL EVENTUALLY DRY OUT. BEHIND THE FRONT...NORTHWEST WINDS WILL GUST UP TO 20 KNOTS IN SOME LOCATIONS BEFORE THE INVERSION SETS UP BRIEFLY. INVERSION BREAK WILL OCCUR TODAY BY 15Z WITH WINDS CONTINUING TO GUST TO 20 KNOTS TODAY. A COOLER AIR MASS IN PLACE TODAY WILL TEMPER HIGHS INTO THE UPPER 40S TO AROUND 50. MEANWHILE...A PROGRESSIVE PATTERN WILL BE IN PLACE IN NORTHWEST FLOW OVER THE OHIO VALLEY. A FAST MOVING WEAK WAVE WILL BEGIN TO TRACK INTO THE OHIO VALLEY AS SOME CIRRUS WILL OVERSPREAD THE AREA BY THIS EVENING. THIS CLOUD COVER WILL HINDER THE RIDGE VALLEY SPLIT TONIGHT WITH VALLEYS DROPPING INTO THE MID 20S AND RIDGES HOVERING AROUND 30 FOR LOWS TONIGHT KEEPING THE SPLIT AT ABOUT 5 DEGREES. HEADING INTO WEDNESDAY...MODEL PROFILES INDICATE A DRY AIR MASS IN PLACE BUT...THERE WILL BE SOME INSTABILITY IN PLACE BY THE AFTERNOON. THIS IN ADDITION WITH WEAK FORCING AND ASSISTANCE FROM OROGRAPHICS WILL BE ENOUGH FOR THE DEVELOPMENT OF SOME AFTERNOON SHOWERS OVER THE AREA. GIVEN THE DRY AIR MASS...HAVE DECIDED TO KEEP SLIGHT CHANCE POPS FOR WEDNESDAY AFTERNOON. GIVEN THE CONVECTIVE PROFILE...HAVE LOWER TEMPS FOR SNOWFALL BUT EVEN THEN...SURFACE TEMPS LOOK TO BE A BIT TOO WARM. TEMPS ON BLACK MOUNTAIN LOOK TO BE JUST COLD ENOUGH FOR SOME SNOWFALL BUT WITH NO ACCUMULATION EXPECTED. WITH THE PROGRESSIVE PATTERN...THE FRONT WILL EXIT THE AREA BY WEDNESDAY EVENING...ALSO SPEAKING OF SOME HIGHER WIND SPEEDS...WINDS WILL BE GUSTY AGAIN FOR WEDNESDAY WITH 20 KNOT WINDS MIXING TO THE SURFACE BY WEDNESDAY AFTERNOON. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 420 AM EDT TUE MAR 19 2013 THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE FIRST PART OF THE EXTENDED BEFORE DIVERGING OVER THE WEEKEND AND INTO THE START OF NEXT WEEK. THEY AGREE THAT A DEEP TROUGH WILL PIVOT OUT OF THE OHIO VALLEY TO END THE WORK WEEK...BUT NOT BEFORE ONE LAST BATCH OF ENERGY SHOOTS THROUGH EAST KENTUCKY WEDNESDAY NIGHT INTO THURSDAY. IN THE WAKE OF THIS...HEIGHTS WILL GRADUALLY RISE THROUGH SATURDAY BEFORE ATTENTION TURNS TO A VEXING TROUGH MOVES OUT OF THE ROCKIES AND INTO THE PLAINS. THIS SYSTEM HAS SHOWN WIDE VARIABILITY WITH ITS PROGRESS EAST IN THE VARIOUS MODELS AND RUNS. ACCORDINGLY...CONFIDENCE REMAINS LOW IN ANY SPECIFIC SOLUTION...THOUGH THE MOST RECENT SET OF MODELS...INCLUDING THE 00Z ECMWF...IS SHOWING A DISTINCT SHIFT TOWARD A CONSENSUS. THIS CONSENSUS IS IN LINE WITH THE LATEST THOUGHTS FROM WPC AND THE ENSEMBLES OF BOTH THE GFS AND ECMWF. THE TROUGH APPEARS TO BE DESTINED TO WRAP UP INTO A LOW THAT WILL CROSS THE TENNESSEE AND OHIO VALLEYS LATER IN THE WEEKEND AND THROUGH THE APPALACHIANS ON MONDAY. THE LATEST ECMWF IS STILL A NOTCH FASTER THAN THE GFS HERE...BUT MUCH CLOSER THAN THE 12Z RUNS. WHILE THIS LEADS TO A BETTER BLEND RESULT...ENOUGH DIFFERENCES REMAIN IN THE DETAILS OF EACH MODEL TO MAKE FOR A LOW CONFIDENCE FORECAST WHEN IT COMES TO ANY WX SPECIFICS...PARTICULARLY FOR DAYS 6 AND 7. AN UNSEASONABLY COLD AIR MASS WILL REMAIN OVER EAST KENTUCKY UNTIL AT LEAST FRIDAY MORNING AS ARCTIC HIGH PRESSURE MOVES THROUGH THE AREA. EARLY IN THE PERIOD...UPPER LEVEL SUPPORT AND LINGERING LOW LEVEL MOISTURE MAY BE ENOUGH TO KICK OFF NORTHWEST FLOW/UPSLOPE SNOW SHOWERS OVER THE HIGHER TERRAIN OF EAST KENTUCKY WEDNESDAY NIGHT INTO THE FIRST PART OF THURSDAY. DRIER WEATHER FOLLOWS INTO FRIDAY BEFORE THE DEVELOPING SFC REFLECTION TO THE WEST STARTS TO SEND MOISTURE INTO OUR SOUTHWEST COUNTIES....SPREADING NORTHEAST WITH TIME. EXPECT THE CLOUDS TO MOVE OVER EAST KENTUCKY FAIRLY EASY...BUT THE PCPN MAY BE MOSTLY SUPPRESSED TO THE SOUTH THROUGH SATURDAY. ANYTHING THAT DOES MANAGE TO SEEP NORTH WILL LIKELY BE MIX OF RAIN AND SNOW AS WARMER AIR WORKS IN AHEAD OF THE LOW...BUT THE COLD AIR LINGERS... PARTICULARLY OVER OUR NORTHEAST COUNTIES. FOR SUNDAY...ALL DEPENDS ON HOW THE SFC LOW AND ITS UPPER SUPPORT COME EAST. A NORTH TRACK...AS DEPICTED IN THE ECMWF...WOULD MEAN MORE OF A RAIN THREAT THAN SNOW... BUT A FURTHER SOUTH ONE...AS IMPLIED BY THE ENSEMBLES...WOULD MORE LIKELY BE A SNOW MAKER...IF ANYTHING. THE FORECAST FOR THE LATTER PART OF THE EXTENDED REPRESENTS A SPLITTING OF THESE DIFFERENCES...BUT NOT NECESSARILY THE MOST LIKELY OUTCOME. MONDAY WILL PROBABLY BE COLDER THAN SUNDAY AS THE LOW HEADS EAST IN THE CONSENSUS SCENARIO...ALLOWING FOR A CONTINUED CHANCE OF SNOW...ALONG WITH THE POTENTIAL FOR A DEEPER AND LARGER STORM THAN INDICATED BY ANY MODEL BLEND. STAY TUNED. THE CR MODEL BLEND CAME IN REASONABLE GIVEN THE MODELS IT USED...BUT WITH THE NEW ECMWF COMING IN JUST AFTER 3 AM...AND WITH A BETTER JOG TOWARD CONSENSUS...DID MAKE SOME MINOR ADJUSTMENT TO POPS FOR THE LATTER PART OF THE FORECAST WITH THAT LATEST RUN IN MIND. ALSO MADE SOME TWEAKS TO OVERNIGHT LOWS FOR TERRAIN EFFECTS FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 123 AM EDT TUE MAR 19 2013 ONLY ISSUE IN THE NEAR TERM FOR THE TAFS IS SOME LOW LEVEL DECKS BEHIND THE FRONT. CURRENT TRENDS HOWEVER HAVE THE LOWER LAYERS FINALLY EXITING THE AREA AFTER 09Z. THE ONLY OTHER ISSUE FOR THE TAFS WILL BE STRONG NORTHWEST WINDS MIXING TO THE SURFACE AND GUSTING TO 20 KNOTS IN SOME LOCATIONS. WINDS SHOULD DIMINISH BY 23Z THIS EVENING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SHALLENBERGER LONG TERM...GREIF AVIATION...SHALLENBERGER