799 FXUS63 KJKL 282022 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 422 PM EDT FRI MAR 28 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 400 PM EDT FRI MAR 28 2014 A COLD FRONT HAS SLOWED ITS SOUTH AND EAST PROGRESS AS AN AREA OF LOW PRESSURE IS BEGINNING TO TAKE SHAPE OVER TX IN RESPONSE TO THE NEXT SHORTWAVE MOVING ACROSS THE PLAINS. THIS SHORTWAVE TROUGH WILL GRADUALLY WORK EAST TO MS RIVER VALLEY AND ENTER THE LOWER OH VALLEY TONIGHT AND THEN INTO THE EASTERN CONUS THROUGH THE END OF THE PERIOD. THE SOUTHERN END OF THE TROUGH IS FORECAST TO CLOSE OFF AND MOVE ACROSS THE AREA LATE SATURDAY AFTERNOON INTO SATURDAY NIGHT. THE SFC LOW IS EXPECTED TO TRACK TO THE CUMBERLAND PLATEAU IN TN BY DAWN ON SATURDAY. THE 12Z GFS IS GENERALLY THE STRONGEST WITH THE SFC LOW AT THAT POINT. THE SFC LOW SHOULD MOVE ACROSS THE SOUTHEAST PART OF THE AREA ON SATURDAY MORNING AND DEEPEN TO ABOUT 995 MB PER THE 12Z ECMWF AND 12Z GFS AS THE UPPER LOW DEVELOPS AND REACH THE DELMARVA BY THE END OF THE PERIOD. DESPITE THE MID LEVEL HEIGHT RISES CAPPING OFF CONVECTION THIS AFTERNOON FROM BRIEF SHORTWAVE RIDGING...THERE IS ENOUGH LOW LEVEL INSTABILITY FOR EXTENSIVE CU AND STRATOCU AND SOME SHOWERS. THESE FEW SHOWERS HAVE RECENTLY DEVELOP NEAR THE STALLING BOUNDARY AS MODEL GUIDANCE HAD SUGGESTED. SOME ISOLATED SHOWERS WILL REMAIN POSSIBLE THIS EVENING...BEFORE MOISTURE AND LIFT INCREASE AHEAD OF THE UPPER LEVEL TROUGH AND SFC WAVE TO TRACK NORTHEAST INTO THE TN VALLEY AND THEN INTO THE REGION BY EARLY ON SATURDAY. THE 12Z ECMWF AND GFS GUIDANCE SUGGEST VERY LITTLE IF ANY MEASURABLE PRECIPITATION TONIGHT WITH SOME DOWNSLOPE FLOW ACROSS MUCH OF THE AREA. HOWEVER... THE NAM AND 9Z AND 15Z SREF WERE IN THE LIKELY TO CAT RANGE IN MOST AREAS ACROSS THE REGION. PERSISTENCE AND ISC COLLABORATION LED TO CATEGORICAL POPS LATE IN ALL BUT THE BIG SANDY REGION. QPF TONIGHT WILL BE LIGHTER AND MUCH MORE SIGNIFICANT WELL WEST OF THE REGION AND WEST OF THE ANTICIPATED SFC LOW TRACK. AS THE SFC LOW TRACKS INTO WV THROUGH EARLY SAT AFTERNOON SOME COLDER AIR WILL BEGIN TO BE WRAPPED SOUTHEAST TOWARD THE REGION. A BAND OF SHOWERS OR RAIN WILL SHIFT EAST INTO EASTERN KY BY THE DAY ON SATURDAY. THIS SHOULD LEAD TO THE MOST WIDESPREAD PRECIP ACROSS THE REGION ON SATURDAY MORNING...WITH SOME DRY SLOTTING IN THE AFTERNOON TO EARLY EVENING...ESPECIALLY IN THE SOUTH AND SOUTHEAST. ELEVATED INSTABILITY DOES LINGER INTO SAT AM...SO AN ISOLATED RUMBLE OR TWO OF THUNDER CANNOT BE RULED OUT. TEMPERATURES WILL BE WARMEST IN THE AM AS THE SFC LOW MOVES ACROSS THE REGION AND THEN TEMPS WILL BEGIN TO DROP OFF DURING SAT AFTERNOON. TEMPS SHOULD REACH THE UPPER 30S TO LOW 40S ACROSS THE NORTH AND HIGHEST TERRAIN BY LATE AFTERNOON. AS THE SOUTHERN PORTION OF THE SHORTWAVE TROUGH CLOSES OFF INTO A CLOSED UPPER LEVEL LOW AND MOVES EAST INTO THE CENTRAL AND SOUTHERN APPALACHIANS... FURTHER COLD AIR ADVECTION AND INSTABILITY AS WELL AS UPSLOPE FLOW WILL LEAD TO ANOTHER ROUND OF SHOWERS MOVING ACROSS THE AREA FROM SAT EVENING INTO WELL INTO SAT NIGHT. THE NON NAM GUIDANCE SUGGESTS SOME DECENT QPF...WHILE THE THERMAL PROFILE GRADUALLY MOVES TOWARD ONE SUPPORTIVE OF SNOW SHOWERS...FIRST ACROSS THE FAR NW AND HIGHEST TERRAIN NEAR THE VA LINE AND THEN INTO THE LOWER ELEVATIONS...POSSIBLY BEFORE THE SHOWER CHANCES END. THE COLLING WOULD COME FROM A COMBINATION OF COLD ADVECTION...COOLING FROM LIFT AND SOME WETBULBING. WITH THE UPPER LOW TRACKING ACROSS THE AREA AT NIGHT...AND ANY SNOW GENERALLY FALLING AT NIGHT AS WELL SOME ACCUMULATION WILL BE POSSIBLE. MOST LOCATIONS WILL NOT GET MORE THAN A DUSTING... IF THAT FROM THIS. HOWEVER...LIGHT ACCUMULATIONS WILL BE POSSIBLE...PARTICULARLY RIDGES AT 2000 FEET AND ABOVE. AMOUNTS AT THESE HIGHEST ELEVATIONS COULD EXCEED 1 INCH WITH THE TOP OF BLACK MTN OR PINE MTN AND PERHAPS THE FLATWOODS AREA OF PIKE COUNTY GETTING AS MUCH AS 2 TO 3 INCHES. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 323 PM EDT FRI MAR 28 2014 THE EXTENDED FORECAST PERIOD BEGINS WITH THE MODELS IN VERY GOOD AGREEMENT. ON SUNDAY THE WILL BE AN UPPER LOW OVER SOUTH CENTRAL VIRGINIA. AT THE SURFACE...THE WRAP AROUND MOISTURE SHOULD SHOULD BE MOVING OUT OF THE AREA AND THE THE PRECIPITATION SHOULD BE ENDING. THE UPPER LOW WILL CONTINUE MOVING TO THE NORTHEAST AND THE NEXT SYSTEM WILL START MOVING TOWARD THE AREA. AS THE SYSTEM APPROACHES ON TUESDAY NIGHT...AN UPPER LOW WILL START DIGGING IN OVER THE WEST COAST. THIS WILL TEND THE KEEP THE FRONT FAIR STATIONARY NEAR EASTERN KENTUCKY. AT THIS TIME THE FRONT WILL BE FAIRLY WEAK AND IT WILL RESULT MOSTLY IN CLOUDS. THERE IS QUITE A BIT OF UNCERTAINTY AS TO EXACTLY WHERE THE FRONT WILL STALL OUT. AS THE UPPER TROUGH OUT WEST CONTINUES TOWARD THE AREA...THE FRONT WILL DEFINITELY BE TO THE NORTH OF THE AREA AND IT WILL KEEP EASTERN KENTUCKY IN THE WARM SECTOR. THE FRONT WILL BE MOVING VERY SLOWLY INTO AND THROUGH THE AREA AS WAVE DEVELOP ON THE FRONT OVER THE SOUTH CENTRAL PLAINS AND KEEP THE FRONT TO THE WEST OF THE AREA. THIS WILL KEEP WARM UNSTABLE AIR OVER EASTERN KENTUCKY AND WILL ALLOW SOME ISOLATED THUNDERSTORMS TO ACCOMPANY THE RAIN. THE FRONT IS EXPECTED TO MOVE ACROSS THE AREA ON THURSDAY NIGHT. BY THE END OF THE PERIOD...THERE MODELS ARE DIFFERING...SO THE TIMING OF THIS FRONT COULD CHANGE 6-18 HOURS BY THE TIME IT GETS HERE. THIS WILL KEEP THE HIGH TEMPERATURES NEAR 70 THROUGH THE EXTENDED PERIOD. ADJUSTED THE MODEL BLEND TOWARD THE NEW ECMWF. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 210 PM EDT FRI MAR 28 2014 A COLD FRONT HAS BEGUN TO STALL ACROSS THE OH VALLEY REGION AS THE FIRST SFC LOW AND ASSOCIATED MID LEVEL DISTURBANCE DEPART AND SFC LOW PRESSURE BEGINS TO ORGANIZE OVER THE SOUTHERN PLAINS. THIS NEXT SFC LOW WILL TRACK ACROSS THE AREA LATE TONIGHT AND INTO SAT. SOME LOCATIONS SHOULD IMPROVE TO VFR FOR A WHILE OVER THE FIRST 6 TO 9 HOURS OF THE PERIOD IN BETWEEN SYSTEMS. CLOUDS WILL REMAIN...JUST ABOVE THE MVFR VFR BREAK IN LOCATIONS THAT DO IMPROVE TO VFR. THIS NEXT LOW WILL BRING RENEWED CHANCES FOR SHOWERS AND POSSIBLY ISOLATED TSRA AS WELL AS ANOTHER LOWERING OF CONDITIONS BACK TO MVFR BETWEEN 8Z AND 14Z. THIS WILL BE AFTER && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JP LONG TERM...JJ AVIATION...JP