Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 260529 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 1229 AM EST WED NOV 26 2014 .UPDATE... ISSUED AT 1136 PM EST TUE NOV 25 2014 DID AN UPDATED MAINLY TO FRESHEN UP THE T AND TD GRIDS PER THE LATEST OBS AND TRENDS. ALSO INCREASED THE SKY COVER SLIGHTLY IN THE FAR NORTHERN COUNTIES OF THE CWA...BASED ON THE LATEST SATELLITE RETURNS. CONTINUE TO AGREE WITH PREVIOUS UPDATE AS FAR AS SNOWFALL TOTALS. THE LATEST NAM12 SEEMS TO HAVE COME IN WITH SLIGHTLY LESS PRECIP THAN THAT OF THE 18Z RUN...WHICH SEEMS TO ACTUALLY MAKE MORE SENSE GIVEN THE STRONG UPTICK IN MOISTURE AT 18Z /SEEMS TO HAVE BEEN A LITTLE ERRONEOUS/. EVEN MORE CONFUSING IS THE LATEST HRRR RUN WHICH IS STILL ONLY BRINGING PRECIP INTO PIKE AND LETCHER COUNTIES OVERNIGHT...WHILE THE REMAINDER OF THE CWA REMAINS DRY. THIS SEEMS A BIT EXTREME AS WELL IN COMPARISON TO THE 6 HOURS MODELS. GIVEN ALL THE UNCERTAINTY...ENDED UP JUST KEEPING SNOW TOTALS THE SAME. ONCE PRECIP MOVES INTO THE REGION...THIS WILL BE THE TIME TO ASSESS THE CURRENT CONDITIONS COMPARED TO THAT OF THE MODEL RUNS...AND ADJUST AMOUNTS /QFP AND SNOW/ UP OR DOWN AS NEEDED. FORECASTED TEMPERATURES ARE ALREADY FAIRLY CLOSE TO THE FREEZING LINE. ANY SHIFT A COUPLE DIRECTIONS ONE WAY OR ANOTHER COULD MEAN THE DIFFERENCE BETWEEN MORE OR LESS SNOW IN A PARTICULAR LOCATION. UPDATE ISSUED AT 725 PM EST TUE NOV 25 2014 DID AN UPDATED MAINLY TO FRESHEN UP THE T AND TD GRIDS PER THE LATEST OBS AND TRENDS. ALSO BUMPED UP THE SKY COVER QUICKER THROUGH THE EVENING AS HIGH CLOUDS HAVE SPREAD IN QUICKLY FROM THE SOUTHWEST. THE 18Z RUNS HAVE COME IN WITH BEEFIER THOUGHTS ON SNOW AS BOTH THE GFS AND NAM12 TAKE THE PCPN FURTHER WEST. THE GFS SEEMS TOO WARM AT THE SFC FOR MUCH SNOW OR ACCUMULATION FOR LOCATIONS OUTSIDE OF OUR CURRENT ADVISORY WITH ITS LATEST RUN. THE NAM12...ON THE OTHER HAND...APPEARS TO GO OVERBOARD ON THE QPF AND THEREFORE SNOW OVER OUR EASTERN COUNTIES. THERE REMAINS PLENTY OF FACTORS THAT WOULD HAMPER THIS OCCURRENCE WITH CONVECTION TO THE SOUTH CUTTING OFF SOME OF THE BEST MOISTURE FROM BEING TRANSPORTED INTO KENTUCKY AS CLEANLY AS ENVISIONED BY THE OFF SYNOPTIC TIME RUN. NEVERTHELESS WILL BE MONITORING THE RADAR TRENDS AND NEAR TERM MODELS FOR SIGNS THAT THE CURRENT FORECAST REMAINS ON TRACK. TO THAT THOUGHT...THE LATEST HRRR RUNS HAVE TRENDED ITS PCPN SHIELD FURTHER TO THE NORTHWEST BUT STILL A FAR CRY FROM THE 6 HOURLY MODELS. THE UPDATED GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 325 PM EST TUE NOV 25 2014 ...ACCUMULATING SNOW EXPECTED OVER FAR EASTERN KENTUCKY TONIGHT INTO WEDNESDAY MORNING... 19Z SFC ANALYSIS SHOWS HIGH PRESSURE STILL INFLUENCING THE WEATHER OF EASTERN KENTUCKY. THIS HAS PROVIDED PLENTY OF SUNSHINE AND GENERALLY SOUTHWEST WINDS OF 5 TO 10 KTS WITH OCCASIONAL GUSTS TO 15 KTS. THESE CONDITIONS...ALONG WITH GOOD DRYING THROUGH EARLY AFTERNOON HAS SENT TEMPERATURES WELL UP INTO THE 50S FOR MOST OF THE AREA...THOUGH LOCATIONS NORTHWEST OF INTERSTATE 64 ARE LAGGING IN THE UPPER 40S. OF NOTE ON THE SFC CHART IS AN AREA OF DEVELOPING LOW PRESSURE CROSSING NORTHERN FLORIDA ON ITS WAY TO THE SOUTHEAST U.S. SEABOARD. THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT THROUGH THE FIRST PART OF THE SHORT TERM FORECAST. THEY ALL TAKE A STRONG SHORTWAVE CURRENTLY BOTTOMING OUT OVER THE CENTRAL GULF COAST NORTHEAST INTO THE SOUTHERN APPALACHIANS BY WEDNESDAY MORNING. IN ADDITION...A COMPACT WAVE WILL BE DROPPING SOUTHEAST FROM THE NORTHERN PLAINS INTO THE MID MISSISSIPPI VALLEY AND EVENTUALLY THROUGH THE TENNESSEE VALLEY LATER WEDNESDAY NIGHT. THE MODELS ARE CLOSE ON THE TIMING OF THIS BUT THE CORE OF THE ENERGY IS FURTHER SOUTH IN THE NAM... ECMWF...AND GEM WHEN COMPARED TO THE GFS. WILL FAVOR THIS MORE SOUTHERN TRACK AS SEEN IN THE CONSENSUS. IN GENERAL HAVE LEANED MOST CLOSELY TO THE HIGHER RESOLUTION MODELS OF THE NAM12 AND HRRR... THOUGH THE HRRR PCPN FIELDS SEEM TOO FAR SOUTHEAST AND SLOW LATER TONIGHT. SENSIBLE WEATHER WILL FEATURE A QUICK INCREASE IN CLOUD COVER FROM THE SOUTHEAST AS THE COASTAL LOW STARTS TO TAKE SHAPE LATER THIS EVENING. LOWER CLOUDS AND PCPN WILL START TO SPILL OVER THE SPINE OF THE APPALACHIANS AND MOVE INTO OUR FAR EASTERN COUNTIES AROUND MIDNIGHT. EXPECT TEMPERATURES TO WET BULB DOWN WHEN THE PCPN MOVES IN AND TRANSITION THE RAIN TO SNOW IN THE HIGHER ELEVATIONS FIRST BUT EVENTUALLY DOWN IN THE VALLEYS...AS WELL. THE HEAVIEST SNOW WILL FALL IN THE HIGHER TERRAIN ALONG THE VIRGINIA BORDER WHERE AS MUCH AS A QUARTER TO A THIRD OF AN INCH OF LIQUID WILL LIKELY OCCUR. THIS WILL PROBABLY AMOUNT TO BETWEEN TWO AND THREE INCHES OF WET SNOW IN THE HIGHER TERRAIN...ABOVE 2000 FEET AND AROUND AN INCH OR LESS ELSEWHERE. HIGHER RIDGES BELOW 2000 FEET CAN EXPECT TO PICK UP BETWEEN ONE AND TWO INCHES BY MIDDAY WEDNESDAY. HAVE SET UP THIS AREA WITH A WINTER WEATHER ADVISORY FROM MIDNIGHT THROUGH NOON WEDNESDAY FOR THIS PASSING EVENT. WITH THE POTENTIAL FOR LIGHT ACCUMULATIONS IN THE COUNTIES IMMEDIATELY WEST OF THE ADVISORY WILL ALSO ISSUE AN SPS ADDRESSING THIS MARGINAL CONCERN. OTHERWISE...THE COASTAL PULLS OUT LATER WEDNESDAY WITH A BRIEF VISIT BY HIGH PRESSURE FOR EAST KENTUCKY IN ITS WAKE. HOWEVER...THE NEXT DEVELOPING LOW WORKS IN FROM THE NORTHWEST LATER THAT NIGHT CARVING ITS WAY THROUGH OUR SOUTHERN COUNTIES INTO DAWN THURSDAY. THIS TOO WILL BRING SOME RAIN OR SNOW TO PARTS OF THE AREA WITH SOME SLUSHY LIGHT SNOW ACCUMULATIONS POSSIBLE MAINLY ON RIDGES AND GRASSY/ELEVATED SURFACES. AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR T/TD/WINDS THROUGH THE NEXT 24 HOURS AND THE SUPERBLEND THEREAFTER. DID MAKE SOME MORE SIGNIFICANT TERRAIN BASED ADJUSTMENTS TONIGHT INTO WEDNESDAY IN THE EXPECTED SNOW AREAS OF THE FAR EAST. AS FOR POPS...ENDED UP CLOSE TO A BLEND OF THE MAV AND MET NUMBERS THROUGH THE PERIOD. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 354 PM EST TUE NOV 25 2014 SHORTWAVE ENERGY ROUNDING THE BASE OF THE TROUGH AND ASSOCIATED LOW PRESSURE WILL BE MOVING EAST OF THE REGION WITH BEST POP CHANCES ACROSS THE SE PORTIONS OF THE CWA. THIS WILL GENERALLY BE LIGHT RAIN/SNOW SHOWERS AND DO NOT EXPECT MUCH QPF THROUGH THE DAY THURSDAY AT THIS POINT. THIS SYSTEM SLIDES EAST ALLOWING FOR NW/W FLOW TO SETUP ACROSS THE REGION AND THEREFORE HELD SLIGHT CHANCE IN FAR SE INTO THE AFTERNOON. SURFACE HIGH PRESSURE WILL SLOWLY SLIDE EAST THROUGH THE NIGHT THURSDAY AND GENERALLY CRESTING ACROSS THE REGION EARLY FRIDAY. THIS HIGH PRESSURE BUILDS EAST BRINGING RETURN SOUTHERLY FLOW TO EASTERN KY WITH TEMPERATURES RISING INTO THE LOWER 50S SATURDAY. SATURDAY AFTERNOON WE DO PRESENT SOME SLIGHT CHANCE SHOWERS ESPECIALLY ACROSS THE FAR NORTH AS FRONTAL BOUNDARY GENERALLY STALLS ACROSS THE NORTH. THIS QUASI-STATIONARY FRONT WILL KEEP THE WEATHER UNSETTLED THROUGH THE PERIOD. THE QUESTION REALLY BECOMES HOW QUICKLY DOES THIS BOUNDARY MOVE SOUTH...THAT SAID THE 12Z ECMWF IS MORE PROGRESSIVE MOVING THIS FRONT SOUTH THAN THE 12Z GFS. RIGHT NOW WITH MODEL DISCREPANCIES WILL KEEP BLEND POPS FOR THE MOST PART BUT WOULD THINK THESE POPS WILL CONTINUE TO TREND UP ONCE MODELS COME INTO BETTER ALIGNMENT. SATURDAY HIGHS ARE EXPECTED TO WARM INTO THE LOW TO MID 50S WITH TEMPERATURES MODIFYING INTO THE UPPER 50S TO LOWER 60S THROUGH THE PERIOD. && .AVIATION...
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(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1228 AM EST WED NOV 26 2014 VFR CONDITIONS WILL CONTINUE AT THE TAF SITES THROUGH AROUND 7Z. AFTER THAT THE AIRPORTS WILL BEGIN TO EXPERIENCES MVFR CIGS AS LOW LEVEL CLOUD AND PRECIPITATION BEGIN OVERSPREADING THE AREA. RAIN AND SNOW WILL BE POSSIBLE INITIALLY...BEFORE COLDER AIR MOVES IN ALOFT AND CHANGES ALL PRECIPITATION OVER TO SNOW. THE SNOW SHOULD BE FAIRLY LIGHT AT JKL AND SJS. ONCE THE SNOW BEGINS...SOME FOG MAY ALSO FORM AT JKL AND SJS. THE COMBINATION OF BOTH PHENOMENA COULD LEAD TO BRIEF PERIODS OF IFR OR EVEN LIFR CONDITIONS AT BOTH AIRPORTS. LOZ WILL BE ON THE FURTHERS WESTERN EXTEND OF ANY PRECIPITATION...AND SHOULD SEE MAINLY MVFR CONDITIONS AT WORST IN WHATEVER PRECIPITATION IS ABLE TO AFFECT THAT AIRPORT. AT THIS TIME...SME LOOKS TO BE IN THE CLEAR AS FAR AS PRECIPITATION IS CONCERNED...BUT COULD EXPERIENCE SOME BRIEF PERIODS OF MVFR FOG...ALSO THIS A LOW CONFIDENCE FORECAST. THE PRECIPITATION SHOULD BE ENDING AT THE AFFECTED AIRPORTS BETWEEN 11 AND 13Z...WITH VFR CONDITIONS EXPECTED THE REST OF THE PERIOD. CLOUD COVER WILL BE PERSISTENT THROUGHOUT THE DAY TODAY...WITH BROKEN TO OVERCAST COVERAGE EXPECTED EVEN AFTER THE PRECIPITATION ENDS.
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&& .JKL WATCHES/WARNINGS/ADVISORIES...
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WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR KYZ087-088-110- 113-115-117>120.
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&& $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...DJ AVIATION...AR

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