Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 050825 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 425 AM EDT THU MAY 5 2016 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 259 AM EDT THU MAY 5 2016 DEEP UPPER LEVEL LOW IS PRESENTLY MOVING ACROSS SOUTHEAST OHIO. EASTERN KENTUCKY REMAINS DRY AS ALL THE SHOWER ACTIVITY HAS SHIFTED SOUTH AND EAST OF THE AREA. HOWEVER...A VORT MAX IS DROPPING SOUTH ON THE BACK SIDE OF THE UPPER LOW WITH SCATTERED TO NUMEROUS SHOWERS DROPPING SOUTHEAST ACROSS SOUTHERN INDIANA...INTO NORTH CENTRAL KENTUCKY. THESE SHOWERS SHOULD CONTINUE TO WORK SOUTHWARD THIS MORNING...AND LIKELY CLIP THE COUNTIES IN THE CUMBERLAND VALLEY...OR AREAS ALONG AND WEST OF I-75. WILL MAINTAIN LIKELY POPS AS THIS ACTIVITY DROPS SOUTH...BUT MAY DECIDE TO GO UP TO CATEGORICAL IF SHOWERS HOLD TOGETHER OVER THE NEXT FEW HOURS. EITHER WAY...LOOKS LIKE A DAMP MORNING FOR THE CUMBERLAND VALLEY. AS THE VORT MAX EXITS SOUTH THIS MORNING...SURFACE WINDS SHOULD BACK TO THE NORTHWEST AND WE MAY SEE SOME UPSLOPE SHOWERS DEVELOP ON THE NORTHEAST FLANK OF THE DEPARTING VORT MAX. WITH 850MB TEMPS GETTING CLOSE TO -1C THIS MORNING...IT WOULD BE POSSIBLE FOR A FEW SNOW FLAKES ON BLACK MOUNTAIN. THIS SHOWER ACTIVITY WOULD MAINLY IMPACT SOUTHEAST KENTUCKY. THIS ACTIVITY WILL THEN SHIFT SOUTH BY MIDDAY. OUR ATTENTION THEN TURNS BACK TO THE NORTH AND EAST AS ANOTHER SHORTWAVE DROPS SOUTH FROM OHIO. THIS TIME AROUND...IT LOOKS LIKE THE EASTERN HALF OF THE FORECAST AREA IS SET TO BE IMPACTED WITH WIDESPREAD SHOWERS DEVELOPING FROM MID TO LATE AFTERNOON. HAVE GONE MUCH HIGHER WITH POPS AS MOISTURE AND LIFT SHOULD BE ABUNDANT. WE ALSO HAVE UPSLOPE FLOW WHICH WILL HELP TO ENHANCE ANY SHOWER ACTIVITY. WHILE MODELS HAD INDICATED SOME WEAK INSTABILITY YESTERDAY...TODAYS RUNS HAVE LOOKED MUCH LESS FAVORABLE...SO DESPITE THE LOW FREEZING LEVELS...WILL MAINTAIN NO THUNDER. IF WE WERE TO GET SOME STORMS...HAIL WOULD BE A DEFINITE POSSIBILITY WITH THE LOW FREEZING LEVELS. BY TONIGHT...THE WAVE WILL EXIT SOUTH...BUT UPSLOPE FLOW WILL CONTINUE. THUS...WILL MAINTAIN SOME LOW POPS FOR SOUTHEAST KENTUCKY OVERNIGHT TO ACCOUNT FOR SOME LINGERING SHOWERS IN THE UPSLOPE FLOW REGIME. FINALLY...ON FRIDAY...ONE LAST WAVE LOOKS TO DROP SOUTH WITH A POSSIBLE UPTICK IN SHOWER ACTIVITY ACROSS EASTERN KENTUCKY. TEMPERATURES WILL BE VERY COOL OVER THE NEXT 24 TO 36 HOURS. WITH TEMPERATURES STARTING OFF AROUND 40 THIS MORNING...HAVE CUT BACK HIGHS FOR TODAY BASICALLY BACK INTO THE LOW 50S...BUT WOULD NOT BE SURPRISED TO SEE A FEW LOCATIONS FAILING TO CRACK 50...ESPECIALLY ON THE RIDGES. LOWS TONIGHT WILL DIP BACK INTO THE 40S...BUT CLOUD COVER SHOULD PREVENT THEM FROM GOING TOO MUCH LOWER THAN HIGHS TODAY. ON FRIDAY...BOUNDARY LAYER SHOULD WARM SLIGHTLY ALLOWING FOR A SLIGHTLY MILDER DAY WITH TEMPERATURES BACK INTO THE 60S. STAYED BELOW GUIDANCE HOWEVER...GIVEN THE UNCERTAINTY WITH CLOUD COVER AND SHOWER ACTIVITY POSSIBLY KEEPING TEMPERATURES A BIT LOWER. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 425 AM EDT THU MAY 5 2016 THE MODELS ARE IN FAIR AGREEMENT ALOFT THROUGH THE EXTENDED PORTION OF THE FORECAST. THEY ALL DEPICT A DEAMPLIFYING OF THE INITIAL BLOCKY PATTERN AS A PAIR OF UPPER LOWS OVER THE CONUS WEAKEN AND SHIFT EAST NORTHEAST. THE MID ATLANTIC ONE WILL LOSE ITS INFLUENCE OVER EASTERN KENTUCKY EARLY IN THE WEEKEND AS IT STARTS TO MOVE OFF SHORE. THIS WILL ALLOW HEIGHT RISES AND RIDGING TO SPREAD INTO THE BLUEGRASS STATE FROM THE SOUTHWEST. THIS RIDGE WILL BE LIMITED FOR OUR PART OF THE REGION BY ADDITIONAL TROUGHINESS OVER THE GREAT LAKES AND EXTENDING SOUTH INTO THE OHIO VALLEY FOR SATURDAY NIGHT AND SUNDAY. THIS WILL ALSO KEEP THE AREA PRIMED FOR WEAK SHORT WAVES TO PASS OVERHEAD IN FAIRLY FAST NORTHWEST FLOW. IN GENERAL...THE GFS IS STRONGER WITH THE GREAT LAKES TROUGH THAN THE OTHER MODELS AND WILL BE DAMPENED OUT VIA THE BLEND FOR GRIDDED FORECAST PURPOSES. MEANWHILE...FOR THE LATTER PART OF THE WEEKEND AND INTO THE NEW WORK WEEK THE WESTERN TROUGH WILL MOVE INTO THE HIGH PLAINS AND OPEN UP ALLOWING BITS OF ITS ENERGY TO SLIP EAST THROUGH THE OHIO VALLEY AND ACROSS THE NORTHERN PORTION OF THE NOW WEAKENING SOUTHEAST RIDGE. THIS ACTION IS PROGRESSIVE ENOUGH THAT IT EVENTUALLY RESULTS IN THE MID LEVEL RIDGE AXIS MOVING OFF TO THE EAST OF KENTUCKY AND MORE BOUTS OF ENERGY MOVING OVER OUR CWA IN SOUTHWEST FLOW. THE PATTERN THEN CONTINUES ITS EVOLUTION THROUGH THE MIDDLE OF NEXT WEEK ENDING UP WITH TROUGHING NORTH OF THE AREA AND FLATTER...MORE ZONAL... HEIGHTS TO THE SOUTH ALONG WITH LIMITED PACKETS OF ENERGY PASSING THROUGH THE REGION. GIVEN THE COMPLICATIONS OF THIS EVOLVING PATTERN WILL STICK FAIRLY CLOSE TO THE BLENDED MODEL SOLUTION THROUGH THE EXTENDED PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE A RETURN TO MORE SEASONABLE TEMPERATURES FOR SATURDAY AS THE STACKED LOW TO OUR EAST LOSES ITS INFLUENCE. AS PART OF THIS PROCESS...A DEVELOPING WARM FRONT PASSES THROUGH KENTUCKY FRIDAY NIGHT INTO EARLY SATURDAY WITH A CHANCE FOR SHOWERS INITIALLY AND THEN THUNDERSTORM POSSIBILITIES THAT AFTERNOON. IN FACT...ANY STORMS THAT MANAGE TO DEVELOP SATURDAY AFTERNOON COULD BECOME STRONG GIVEN MODERATE CAPE...LOW LIS...AND VEERING WINDS WITH HEIGHT. A COLD FRONT WILL THEN SLIP SOUTH INTO THE AREA SATURDAY NIGHT INTO SUNDAY. THIS FRONT WILL HANG UP OVER EAST KENTUCKY INTO THE START THE NEW WEEK. WITH THIS...SHOWERS AND THUNDERSTORMS CAN BE ANTICIPATED. ON SUNDAY THE FRONT AND PCPN WILL LIKELY KEEP TEMPS IN THE 60S FOR HIGHS OVER ALL BUT THE FAR SOUTHWEST. TEMPERATURES WILL DO BETTER FOR THE REST OF THE WEEK AS THE FRONT LIFTS BACK NORTH WITH MID AND UPPER 70S ANTICIPATED. THIS SHOULD BE ENOUGH TO FUEL THE INSTABILITY ALLOWING FOR CHANCES OF THUNDERSTORMS ALONG WITH ANY SHOWERS DURING THE BULK OF THE EXTENDED FORECAST. AS FOR THE CR INIT...MADE ONLY MINOR ADJUSTMENT TO TEMPERATURES EACH NIGHT ANTICIPATING MINIMAL RIDGE TO VALLEY DIFFERENCES ASIDE FROM SATURDAY AND TUESDAY MORNINGS. ALSO TWEAKED THE POPS FOR THE LATTER PART OF THE FORECAST MORE ALONG THE LINES OF THE LATEST ECMWF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 133 AM EDT THU MAY 5 2016 WHILE MAINLY VFR CONDITIONS DOMINATE PRESENTLY...WE WILL SEE CIGS START TO COME DOWN TOWARDS DAYBREAK...AS A UPPER LEVEL WAVE DROPS SOUTH ACROSS CENTRAL AND EASTERN KENTUCKY. LAMP GUIDANCE HAS MAINLY JUST MVFR CIGS THROUGH THE MORNING HOURS AND WILL GO THIS ROUTE IN THE TAFS. CIGS SHOULD LIFT TO VFR BY MIDDAY...WITH A BRIEF PERIOD OF VFR EXPECTED THIS AFTERNOON. HOWEVER...ANOTHER WAVE WILL DROP IN FROM THE NORTH LATER THIS AFTERNOON AND EVENING...WITH MORE RAIN SHOWERS AND CIGS AGAIN DROPPING BACK TO MVFR. UPSLOPE FLOW MAY KEEP THE LOW CLOUDS IN PLACE THROUGH THURSDAY NIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...KAS LONG TERM...GREIF AVIATION...KAS

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