Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 310532 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 132 AM EDT FRI OCT 31 2014 .UPDATE...
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ISSUED AT 132 AM EDT FRI OCT 31 2014 SENT OUT A QUICK UPDATE TO ACCOUNT FOR THE COOLER TEMPERATURES IN THE WEST...AS SOME LOCATIONS HAVE DROPPED DOWN INTO THE MID TO UPPER 30S. CLOUDS ARE NOW FINALLY STARTING TO MOVE IN...SO EXPECT THE TEMPERATURES TO COME UP SOME AS THE BLANKET MOVES IN OVERHEAD. THE REST OF THE FORECAST REMAINS ON TRACK. UPDATE ISSUED AT 1050 PM EDT THU OCT 30 2014 HOURLY GRIDS HAVE BEEN UPDATED BASED ON RECENT OBS AND SATELLITE IMAGERY. THIS LED TO NO SIGNIFICANT CHANGES. UPDATE ISSUED AT 835 PM EDT THU OCT 30 2014 HOURLY GRIDS HAVE BEEN UPDATED TO LOWER TEMPERATURES OVER THE NEXT FEW HOURS BEFORE CLOUDS ARE EXPECTED TO INCREASE OVERNIGHT. EASTERN VALLEY TEMPERATURES ARE ALREADY RUNNING IN THE UPPER 30S SO THE HOURLY TEMP GRID HAS BEEN MODIFIED FOR A MIN T AROUND OR BEFORE 6Z...2 AM. DEWPOINTS ARE ALSO SUPPORTIVE OF PATCHY FROST FOR THESE AREAS AND IT HAS BEEN ADDED TO THE GRIDS. AS FOR THE UPCOMING SYSTEM...THE CURRENT FORECAST AND HEADLINES HAVE THE SITUATION COVERED WELL AND NO CHANGES ARE NEEDED AT THIS TIME. DUE TO THE EARLY SEASON NATURE OF THE EVENT...THE HIGHER TERRAIN OF 1500 FEET ELEVATION AND ABOVE WILL BE FAVORED. IT WILL BE INTERESTING TO SEE IF THE 0Z NAM REMAINS AS WARM WITH BOUNDARY LAYER TEMPS AS THE 18Z RUN AND EARLIER RUNS.
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&& .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 408 PM EDT THU OCT 30 2014 THE FIRST SNOW OF SEASON IS STILL EXPECTED TO IMPACT EASTERN KY AS WE HEAD INTO THE WEEKEND. UNFORTUNATELY...THIS SYSTEM WILL BEGIN IMPACTING THE REGION JUST IN TIME FOR THE TRICK OR TREATING FESTIVITIES...WITH RAIN AND CHILLY TEMPS EXPECTED THROUGH THE EVENING. MODELS ARE ALL IN DECENT AGREEMENT STILL THAT A CLOSED LOW /CURRENTLY RESIDING IN QUEBEC/ WILL DIVE SOUTHWARD INTO EASTERN KY BETWEEN 0Z AND 6Z SATURDAY. THIS SHORTWAVE/CLOSED LOW WILL BE THE MAIN WEATHER DRIVER AS IT NEARS...TRAVERSES...AND EXITS EASTERN KY TO THE SE LESS THAN 24 HOURS LATER. WHILE THE OVERALL MODEL PATTERN AGREES FAIRLY WELL...VERY SUBTLE DIFFERENCES IN THE EXACT PLACEMENT OF THE CLOSED LOW AS IT MOVES OVER EASTERN KY COULD LEAD TO LARGER DIFFERENCES IN SURFACE FEATURES. TEMPERATURES WILL BEGIN COOLING CONSIDERABLY DURING THE DAY FRIDAY AS A SURFACE COLD FRONT SWEEPS EASTWARD THROUGH THE CWA. WINDS WILL PICK UP AS WELL BEHIND THE FRONTAL PASSAGE...WITH EVEN HIGHER WINDS ALOFT DUE TO THE STRONG PRESSURE GRADIENTS BETWEEN THE CLOSED LOW AND STRONG RIDGING OVER THE GREAT PLAINS. PRECIP SHOULD MOVE IN ALONG AND JUST BEHIND THE ACTUAL COLD FRONT...WITH KY BEING ON THE SOUTHWARD EXTENT OF THE CLOSED LOW AND PRECIP AS IT BEGINS AROUND 12Z FRIDAY. UNFORTUNATELY...THE SLIGHT DIFFERENCES IN THE PATHS/TIMING OF THE CLOSED UPPER LEVEL LOW...WILL LEAD TO SLIGHT VARIATIONS IN MODEL DEPICTED PRECIP AS IT ENTERS INTO KY. BUT GENERALLY PRECIP SHOULD START OFF LIGHT ENTERING THE REGION FROM THE NW AROUND 12Z FRIDAY...THEN SPREAD SE AND INTENSIFY THROUGHOUT THE DAY AS THE UPPER LEVEL LOW AND CENTER OF MOISTURE MOVE INTO THE REGION. MODELS ARE STILL SHOWING SIGNS OF ELEVATED INSTABILITY DURING THE AFTERNOON HOURS FRIDAY...SO WILL KEEP MENTION OF ISOLATED THUNDER POSSIBILITY IN THE HEAVIEST RAIN. AS WAS NOTED IN THE PREVIOUS FORECAST...THE LATEST NAM AND GFS ARE STILL SHOWING TWO SEPARATE SHOTS OF MOISTURE. ONE ALONG THE SE FLANK OF THE LOW...A BRIEF BREAK AS THE LOW MOVES IN OVERHEAD...AND THEN ANOTHER BAND OF WRAP AROUND MOISTURE QUICKLY DEVELOPING ALONG THE DEFORMATION ZONE. BY THE TIME THE LOW GETS DIRECTLY OVERHEAD LATE FRIDAY EVENING...TEMPS WILL BEGIN FALLING BELOW FREEZING. IT IS AT THIS POINT THAT WE CAN EXPECT ANY RAIN ACROSS THE REGION TO TRANSITION TO SNOW FROM WEST TO EAST. IT IS ALSO AT THIS POINT WE ARE EXPECTING SOME OF OUR HIGHEST QPF VALUES TO CONCENTRATE OVER THE FAR EASTERN PORTION OF THE STATE. THIS...IN ADDITION TO UPSLOPE FLOW...WILL LEAD TO HIGHEST ACCUMULATIONS OVER THE SE TERRAIN. ELSEWHERE...SNOW WILL FALL...BUT GROUND TEMPS SHOULD FALL SLOWER THAN AIR TEMPS...AND AS A RESULT...MANY AREAS WILL HAVE A HARD TIME SEEING ACCUMULATING SNOW /EXCEPT FOR MAYBE SOME GRASSY SURFACES/. FRIDAY NIGHT...STILL EXPECTING A DUSTING AT MOST IN THE FAR WESTERN COUNTIES...A FEW TENTHS OF AN INCH TO AROUND HALF OF AN INCH OF SLUSHY SNOW /DEPENDENT ON TERRAIN/ ACROSS THE CENTRAL PORTION OF THE CWA...AND UP TO AROUND 2 INCHES IN THE SE ALONG THE HIGHEST TERRAIN. BLACK MOUNTAIN...THE HIGHEST PEAK IN THE CWA...SHOULD BENEFIT WELL FROM THIS UPSLOPE FLOW...WITH BETWEEN 3 AND 4 INCHES FORECASTED FOR THIS POINT THROUGH SATURDAY MORNING. AFTER COORDINATION WITH NEIGHBORING OFFICES...HAVE DECIDED TO GO WITH A WINTER WEATHER ADVISORY FOR BELL...HARLAN...LETCHER...AND PIKE COUNTIES. GRANTED...ONLY A FEW OF THE HIGHEST LOCATIONS IN THESE COUNTIES WILL PROBABLY VERIFY IN THE CRITERIA...BUT GIVEN THAT THIS IS THE FIRST SNOW OF THE SEASON...AND THE FIRST OF THE MONTH WHEN TRAFFIC IS USUALLY HEAVIER...THINK THIS WILL BE MORE OF AN IMPACT BASED EVENT. IN ADDITION TO THE SNOW...BELOW FREEZING TEMPERATURES WILL BE OF CONCERN FRIDAY NIGHT. AS SUCH...AFTER COORDINATION WITH SURROUNDING OFFICES...HAVE AGREED TO ISSUE A FREEZE WATCH FOR THE CWA BOTH FRIDAY NIGHT/SATURDAY MORN AND SATURDAY NIGHT/SUNDAY MORN. TEMPERATURES ARE STILL A BIT TOO BORDERLINE TOMORROW NIGHT TO WANT TO LEAN TOWARDS ANY SORT OF ADVISORY AT THIS POINT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 320 PM EDT THU OCT 30 2014 THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT TO START THE EXTENDED AS THEY ALL TAKE AN EXTREMELY ANOMALOUS LOW THROUGH THE SOUTHERN APPALACHIANS AND TO THE SOUTHEAST ATLANTIC COAST BY MIDDAY SATURDAY. THE NAM12 AND GFS ARE MOST SIMILAR WITH THIS WHILE THE 00Z ECMWF IS A TAD WEAKER BUT IN THE SAME AREA. THE GEM...THOUGH...IS MUCH WEAKER AND DOESN/T EVEN CLOSE OFF THIS LOW LIKE THE OTHER MODELS... THEREFORE IT HAS BEEN DISCOUNTED. ENERGY DIVING SOUTH THROUGH THE CENTRAL APPALACHIANS SATURDAY NIGHT WILL ADD TO THE UPPER LOW ALONG THE COAST AS SEEN IN BOTH THE GFS AND 00Z ECMWF. RIDGING TO THE WEST WILL QUICKLY SHIFT THIS LARGE TROUGH EAST ON SUNDAY. THIS RIDGE WILL HOLD OVER KENTUCKY THROUGH THE START OF THE NEW WORK WEEK BEFORE BEING SHUNTED EAST BY A PAIR OF SPLIT FLOW TROUGHS MOVING INTO THE PLAINS. ENERGY ASSOCIATED WITH THESE WILL START TO STREAM THROUGH THE OHIO VALLEY ON TUESDAY WITH MORE ROBUST AMOUNTS REACHING KENTUCKY BY WEDNESDAY MORNING. THE MODELS DO START TO DIVERGE HERE WITH THE ECMWF INSISTENT ON A DEEP CLOSED LOW HOLDING BACK OVER NORTHERN MEXICO WHILE THE GFS IS MORE PROGRESSIVE SHOWING JUST AN OPEN WAVE MOVING THROUGH CENTRAL TEXAS. THESE DIFFERENCES CONTINUE THROUGH THE REST OF THE EXTENDED PORTION OF THE FORECAST AND LEADS TO LOW CONFIDENCE IN ANY MODEL/S SPECIFICS. THEY DO COLLECTIVELY SUGGEST THAT THE NORTHERN STREAM AND ITS NORTHWEST FLOW WILL DOMINATE THE WEATHER THROUGH EAST KENTUCKY WITH AMPLE ENERGY AND LOWERING HEIGHTS. HAVE FOLLOWED THE CONSENSUS FORECAST FOR THE BULK OF THE EXTENDED THOUGH DID FAVOR A BLEND OF THE NAM12 AND ECMWF FOR THE FIRST PART OF IT. SENSIBLE WEATHER WILL FEATURE THE BACK EDGE OF AN EARLY SEASON WINTER STORM EXITING THE AREA ON SATURDAY. CAA WILL KEEP MUCH OF THE PCPN AS SNOW BEFORE FADING TO FLURRIES AND DRIZZLE FROM WEST TO EAST THAT AFTERNOON. A LOSS OF ICE CRYSTALS DURING THE DAY WILL LIKELY RESULT IN AREAS OF DRIZZLE LASTING INTO SATURDAY NIGHT FOR MUCH OF THE AREA. HOWEVER...TEMPERATURES FALLING TO AND BELOW FREEZING THAT NIGHT WILL MEAN A THREAT OF FREEZING DRIZZLE FOR AT LEAST THE HIGHER TERRAIN OF FAR EASTERN KENTUCKY. IN ADDITION...CLOUDS AND PCPN MAY LIMIT THE DROP OFF IN TEMPERATURES ANTICIPATED FOR THAT NIGHT...SO A HARD FREEZE IS NOT THE SLAM DUNK IT ONCE LOOKED LIKE. THE WINTRY MESS OF PCPN DEPARTS EVEN THE FAR EAST EARLY SUNDAY MORNING WITH CLEARING TAKING PLACE LATER IN THE DAY. THIS CLEARING AND THE MOVEMENT OF SFC HIGH PRESSURE INTO THE REGION WILL MEAN THE BEST SHOT AT A HARD FREEZE FOR THE AREA WILL TAKE PLACE THAT NIGHT... WORSE IN THE VALLEYS. MILDER WEATHER THEN FOLLOWS FOR THE REST OF THE EXTENDED...THOUGH HIGH PRESSURE WILL SHIFT OFF TO THE EAST BY MIDWEEK ALLOWING A SLOW MOVING COLD FRONT TO SET UP TO THE NORTHWEST OF THE STATE AND DROP SOUTHEAST MIDWEEK. THIS BOUNDARY IS EXPECTED TO BRING A BOUT OR TWO OF SHOWERS TO THE AREA FROM LATE TUESDAY THROUGH THURSDAY. THE CR GRID LOAD PROVED TO BE A PRETTY GOOD START WITH CHANGES MADE MAINLY TO ADJUST POPS TOWARD THE LATEST NAM12 AND ECMWF SOLUTION EARLY ON. DID ALSO ADD SOME RIDGE AND VALLEY EFFECTS INTO THE LOW TEMPERATURE GRIDS EACH NIGHT OF THE EXTENDED...BUT AGAIN PARTICULARLY EARLY ON. && .AVIATION...
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(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 132 AM EDT FRI OCT 31 2014 CLOUDS WILL GRADUALLY LOWER WITH TIME THROUGH THE DAY...REACHING MVFR STATUS DURING THE AFTERNOON AS STEADIER PRECIPITATION MOVES IN. CONDITIONS WILL CONTINUE TO WORSEN THROUGH TONIGHT...AS MUCH COLDER AIR BEGINS TO CHANGE THE RAIN TO SNOW...FIRST IN THE HIGHEST ELEVATIONS OF EASTERN KENTUCKY CLOSER TO 00Z. SNOW LEVELS WILL GRADUALLY LOWER DOWN TO THE VALLEYS WITH TIME THROUGH 06Z AND BEYOND. CEILINGS AND VISIBILITIES WILL LIKELY DROP INTO THE IFR RANGE...WITH LIFR OR WORSE CONDITIONS EXPECTED ACROSS THE HIGHER ELEVATIONS IN THE SOUTHEAST. LIGHT AND VARIABLE WINDS WILL GRADUALLY TURN TO THE NORTHWEST LATER TODAY AND INCREASE TO 5 TO 10 KTS.
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&& .JKL WATCHES/WARNINGS/ADVISORIES...
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FREEZE WATCH FROM LATE TONIGHT THROUGH SATURDAY MORNING FOR KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120. FREEZE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120. WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 2 PM EDT SATURDAY FOR KYZ087-088-118-120.
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&& $$ UPDATE...GEOGERIAN SHORT TERM...JMW LONG TERM...GREIF AVIATION...GEOGERIAN

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