Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 200806 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 306 AM EST SAT DEC 20 2014 .SHORT TERM...
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(TODAY THROUGH SUNDAY) ISSUED AT 306 AM EST SAT DEC 20 2014 THE LATEST RUNS OF MOST OF THE FORECAST MODELS HAVE PICKED UP ON THE FACT THAT LITTLE IF ANY PRECIPITATION IS REACHING THE GROUND ACROSS CENTRAL AND EASTERN KENTUCKY SO FAR THIS MORNING. SURFACE OBS FROM AROUND THE STATE OF KENTUCKY HAVE BEEN SHOWING NO MEASURABLE PRECIP ACROSS THE AREA FOR THE PAST FEW HOURS. AN UPPER LEVEL DISTURBANCE HAS BEEN PRODUCING WIDESPREAD CLOUD COVER ACROSS THE AREA TONIGHT...BUT NO MUCH MORE THAN THAT THUS FAR. WITH THIS SYSTEM QUICKLY PULLING OFF TO THE EAST ACROSS THE OHIO VALLEY...AND WITH NOT MUCH IN THE WAY OF LOW LEVEL MOISTURE IN PLACE...THE CURRENT THINKING IS THAT LITTLE IF ANY PRECIPITATION WILL OCCUR AT ANY POINT DURING THE REMAINDER OF THE OVERNIGHT PERIOD OR DURING THE DAY TODAY. THAT BEING SAID...HAVE LOWERED PRECIPITATION CHANCES FROM NOW THROUGH EARLY THIS AFTERNOON BY QUITE A BIT...AND HAVE THE ENTIRE AREA PRECIP FREE BY 18Z. THE ONLY REASON EVEN LOW SLIGHT CHANCE POPS WERE LEFT IN THE FORECAST IS THE FACT THAT A NUMBER OF PRECIP TYPE ECHOES ARE STILL SHOWING UP ON RADAR IMAGERY FROM AROUND THE AREA. ALSO...THE MODEL SOUNDINGS ARE STILL SHOWING A VERY SMALL CHANCE THAT SOME MEASURABLE PRECIP COULD REACH THE GROUND OVER THE NEXT SEVERAL HOURS. WILL GO WITH THIS THINKING FOR NOW...BUT MAY NEED TO UPDATE THE FORECAST BEFORE THE END OF THE SHIFT IF THINGS DO NOT PAN OUT AS PLANNED. TEMPERATURES WILL CONTINUE TO RUN SLIGHTLY BELOW NORMAL TODAY DUE TO EXTENSIVE CLOUD COVER AND NORTHERLY WINDS. TEMPERATURES ON SUNDAY ARE EXPECTED TO BE SLIGHTLY WARMER THAN NORMAL...AS EAST TO SOUTHEASTERLY FLOW SETS UP DOWNSLOPE WARMING ACROSS THE AREA AND CLOUDS THINS OUT BEHIND THE DEPARTED UPPER LOW. HIGHS ON SUNDAY COULD TOP OUT IN THE MID TO UPPER 40S FOR MOST LOCATIONS...WITH A FEW READINGS AT OR SLIGHTLY ABOVE 50 NORTH OF THE TENNESSEE BORDER AND ALONG AND SOUTH OF THE HAL ROGERS PARKWAY. A WEAK RIDGE OF HIGH PRESSURE ALOFT WILL BE THE WEATHER MAKER ACROSS THE REGION TO END THE WEEKEND. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 306 AM EST SAT DEC 20 2014 ACTIVE PATTERN STILL EXPECTED THROUGH CHRISTMAS WEEK. IN FACT...FIRST SYSTEM WILL BE PUSHING NORTHEAST ALONG THE SPINE OF THE APPALACHIANS TO START THE NEW WORK WEEK. NAM REMAINS THE MOST AGGRESSIVE WITH THE NORTHWEST EXTENSION OF PRECIPITATION. STILL NOT CONVINCED WE WILL OVERCOME THE DOWNSLOPING SOUTHEAST FLOW. THUS...HAVE CUT BACK ON POPS INTO THE SLIGHT CHANCE CATEGORY. GFS SEEMS TO BE CATCHING ONTO THE DOWNSLOPING THE BEST...ALTHOUGH THIS MAY BE DUE TO THE FACT IT DOES NOT CONTAIN AS MANY SHALLOW LAYERS AS THE NAM DOES. REGARDLESS...THE PATTERN DOES NOT SUPPORT MUCH PRECIPITATION AND IT SHOULD BE A FAST MOVER WITH CHANCES MAINLY DURING THE MORNING HOURS. ANY PRECIPITATION WILL REMAIN ALL RAIN AS MILDER CONDITIONS SPREAD NORTHWARD WITH THE SYSTEM. BY MONDAY AFTERNOON INTO TUESDAY...SOUTHEAST FLOW ONLY STRENGTHENS THROUGH THIS PERIOD...LIKELY KEEPING THE AREA DRY. MUCH MILDER AIR WILL ALSO SPREAD NORTHWARD. THIS WILL SET UP A FEW VERY MILD DAYS FOR MID TO LATE DECEMBER WITH HIGHS IN THE 50S ON MONDAY AND AROUND 60 BY TUESDAY. GUIDANCE IS HIGHER WITH TEMPERATURES INTO TUESDAY...BUT OPTED TO STAY JUST UNDER THESE NUMBERS AS MID/HIGH CLOUDS COULD KEEP TEMPERATURES DOWN SLIGHTLY. BY TUESDAY NIGHT...A NORTHERN STREAM WAVE IS EXPECTED TO PHASE WITH THE SOUTHERN STREAM WITH AN AREA OF LOW PRESSURE DEVELOPING ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. THIS SYSTEM WILL QUICKLY PUSH NORTHWARD INTO THE GREAT LAKES BY MIDDAY WEDNESDAY...AS IT QUICKLY DEEPENS. LATEST 00Z ECMWF HAS SLOWED EVERYTHING DOWN A BIT INTO THE DAY WEDNESDAY...SO HAVE TRENDED TOWARDS A SLIGHTLY SLOWER EVOLUTION WITH THE FORECAST. REGARDLESS...THIS SYSTEM WILL SEND A VERY STRONG COLD FRONT ACROSS EASTERN KENTUCKY LATE TUESDAY NIGHT THROUGH WEDNESDAY. STRONG FORCING WILL YIELD WIDESPREAD SHOWERS AS THE FRONT PUSHES EAST. THE STRONG DYNAMICS ALONE COULD SUPPORT SOME THUNDER LATE TUESDAY NIGHT INTO WEDNESDAY MORNING...BUT OPTED TO LEAVE IT OUT FOR ONE MORE FORECAST CYCLE AND SEE IF MODELS MIGHT SHOW MORE SUPPORT IN THE NEXT FEW RUNS. GOING TO BE QUITE WINDY AS WELL WEDNESDAY INTO WEDNESDAY NIGHT AS THIS SYSTEM DEEPENS. SOME WIND GUSTS UP TO 35 OR 40 MPH MAY BE POSSIBLE. STAYED ABOVE GUIDANCE FOR LOWS TUESDAY NIGHT (AROUND 50) AS WE SHOULD STAY WELL MIXED AHEAD OF SUCH A STRONG FRONT. HIGHS WEDNESDAY WILL LIKELY OCCUR EARLY AS THE FRONT WILL BRING CRASHING TEMPERATURES THROUGH THE DAY WEDNESDAY. A SECOND WAVE WILL PUSH EAST THROUGH THE AFTERNOON AND EVENING...KEEPING PRECIPITATION GOING. THE COLD AIR WILL BRING A TRANSITION OVER SNOW AS WE HEAD THROUGH WEDNESDAY AFTERNOON AND EVENING. WHILE TEMPERATURES SHOULD STAY ABOVE FREEZING THROUGH EARLY EVENING...IF SNOWFALL RATES CAN GET GOOD ENOUGH...WE COULD SEE A LIGHT COATING BY LATE IN THE DAY IN SOME AREAS. ISOLATED TO SCATTERED SNOW SHOWERS WILL LINGER INTO WEDNESDAY NIGHT...ALTHOUGH MODELS ARE SHOWING A FASTER EXIT OF THE MOISTURE...SO THE WINDOW FOR SNOW ACCUMULATIONS WILL NOT BE ALL THAT BIG. THUS...ANY ACCUMULATION WILL REMAIN LIGHT...LIKELY UNDER AN INCH...EXCEPT FOR PERHAPS THE HIGHER RIDGES WHERE AN EARLIER TRANSITION WILL BE POSSIBLE. BY CHRISTMAS...RIDGING SPREADS BACK INTO THE AREA...SETTING UP A QUITE CHRISTMAS DAY. TEMPERATURES WILL BE COOLER WITH HIGHS ONLY INTO THE LOW 40S. OUR NEXT WEATHER SYSTEM WILL TAKE SHAPE BY FRIDAY...BUT THE TRACK IS EXPECTED TO REMAIN WELL NORTHWEST OF KENTUCKY AT THIS TIME...WHICH WILL KEEP PRECIPITATION FRIDAY NIGHT INTO SATURDAY WITH AN ADVANCING COLD FRONT ALL IN THE FORM OF RAIN. THIS WILL ALSO MEAN MILDER WEATHER RETURNS FROM FRIDAY INTO SATURDAY...BEFORE A RETURN TO COLDER WEATHER BY NEXT SUNDAY.
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&& .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 106 AM EST SAT DEC 20 2014 TAF FORECAST REMAINS A CHALLENGE IN REGARDS TO PRECIPITATION ONSET NEAR LOZ AND SME AND THE NORTHWARD EXTENT OF ANY PRECIP THAT DOES FORM. BASED ON SURROUNDING OBS AND THE LATEST MODEL DATA...IT APPEARS THAT MVFR CONDITIONS WILL THE WORST WE SEE AT ANY OF THE TAF SITES OVERNIGHT AND THROUGH THE DAY ON SATURDAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...AR LONG TERM...KAS AVIATION...AR

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