Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 281840 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 140 PM EST WED JAN 28 2015 .UPDATE... ISSUED AT 140 PM EST WED JAN 28 2015 FEELING FULL EFFECTS OF AMPLE SUNSHINE THIS AFTERNOON WITH ONLY SOME PATCHY CIRRUS TO CONTEND WITH OVER THE NEXT SEVERAL HOURS. OVERALL THE CURRENT FORECAST IS IN GOOD SHAPE AND ONLY UPDATED THE FORECAST PACKAGE TO BRING GRIDS IN LINE WITH HOURLY OBS. UPDATE ISSUED AT 1007 AM EST WED JAN 28 2015 MOSTLY SUNNY SKIES WILL ALLOW FOR A DECENT REBOUND IN TEMPS THIS AFTERNOON. BUT PERSISTENT LOW CLOUDS AND LIGHT SNOW AND FLURRIES CONTINUE TO PLAGUE PIKE COUNTY THIS MORNING. WITH SUCH A SHALLOW LAYER OF MOISTURE NOTHING HAS BEEN SHOWING UP ON RADAR. HOWEVER... KPBX HAS BEEN REPORTING LIGHT SNOW ON AND OFF THIS MORNING. THE VISIBILITY EVEN DROPPED BELOW 2 MILES FOR A PERIOD OF TIME...1 3/4 SM. SO SNOWFALL IS A LITTLE HEAVIER THAN JUST THE ISOLATED FLURRY OR TWO WITH SOME VERY LOCALIZED UPSLOPE LIFTING GOING ON IN THAT AREA. UPDATED THE FORECAST PACKAGE TO MENTION SOME LIGHT SNOW FLURRY ACTIVITY IN THE EXTREME SOUTHEASTERN PORTIONS OF THE CWA FOR A COUPLE MORE HOURS. ALSO BROUGHT GRIDS IN LINE WITH HOURLY OBS. UPDATE ISSUED AT 655 AM EST WED JAN 28 2015 STILL SOME LOW CLOUDS OVER THE FAR EAST ALONG WITH A STRAY FLURRY POSSIBLE. HAVE SLOWED THIS CLEARING DOWN AND ALSO FINE TUNED THE HOURLY TEMPS AND DEW POINTS FOR THE NEXT SEVERAL HOURS BASED ON THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 350 AM EST WED JAN 28 2015 08Z SFC ANALYSIS SHOWS HIGH PRESSURE MOVING THROUGH THE OHIO VALLEY. THIS HIGH IS PROVIDING A DECENT NIGHT OF RADIATIONAL COOLING FOR THE VAST MAJORITY OF THE AREA WITH THE ONLY EXCEPTION FOUND IN FAR EASTERN PARTS OF THE STATE WHERE NORTHEAST LOW LEVEL FLOW IS KEEPING SOME STRATUS AROUND. IN FACT...A FEW SNOW SHOWERS HAVE BEEN FALLING OUT OF THESE AS SEEN IN THE KPBX OBS AND THE RADAR IMAGES FROM RLX. IN THE CLEAR AREAS TEMPERATURES HAVE BEEN FALLING STEADILY WITH THE RIDGES AND THE VALLEYS LEADING THE PACK...THOUGH AS THE NIGHT HAS WORN ON THE DEEPER VALLEYS HAVE DROPPED THE FURTHEST...WHILE THE MORE OPEN LOCATIONS HAVE BEEN LAGGING...THUS FAR. READINGS AT 3 AM VARY FROM THE MID TEENS ON THE RIDGES AND THOSE SHELTERED VALLEYS WHILE LOWER 20S ARE FOUND IN MORE OPEN PLACES LIKE SME AND LOZ AS WELL AS SOUTHERN VALLEYS OF EKQ AND 1A6. DEW POINTS...MEANWHILE...ARE GENERALLY IN THE MID TEENS TO NEAR 10 ABOVE AS WINDS REMAIN LIGHT... GENERALLY FROM THE NORTH TO NORTHEAST. THE MODELS ARE IN PRETTY GOOD AGREEMENT ALOFT FOR THE SHORT TERM PORTION OF THE FORECAST AS THEY ALL DEPICT THE RETREAT OF THE DEEP NORTHEAST TROUGH AND WITH IT THE ENERGY STREAM THAT RAN FROM NNW TO SSE OVER OUR EASTERN BORDER. BRIEF RIDGING WILL FOLLOW INTO THURSDAY MORNING FOR KENTUCKY THOUGH ANOTHER DEVELOPING TROUGH WILL BE TRAILING QUICKLY BEHIND THESE HIGHER HEIGHTS. THIS TROUGH SLIPS INTO THE SOUTHERN OHIO VALLEY BY MIDDAY THURSDAY WITH A COUPLE OF BATCHES OF TRAILING ENERGY THAT WILL EVENTUALLY FORM A DEEPER TROUGH FOR THE NORTHEAST COAST BY WEEK/S END. GIVEN THE MODEL SIMILARITIES IN THE SHORT TERM...HAVE FAVORED A BLENDED SOLUTION WITH A LEAN TOWARD THE NAM12 FOR WX DETAILS ON THURSDAY. SENSIBLE WEATHER WILL FEATURE A CHILLY START TO THE DAY WITH SOME SINGLE DIGITS POSSIBLE AT DAWN. PLENTY OF SUNSHINE WILL ALLOW READINGS TO CLIMB SMARTLY INTO THE MID 30S IN THE NORTH AND LOWER 40S SOUTH EVEN AS HIGH CLOUDS START TO ARRIVE AHEAD OF THE NEXT CLIPPER SYSTEM. THESE HIGH CLOUDS...AND WINDS STARTING TO REACT TO THE SFC LOW...WILL LIKELY NOT PREVENT A DECENT DROP OFF IN TEMPERATURES FOLLOWING SUNSET FOR THE BULK OF THE AREA TONIGHT. EXPECT THE EASTERN VALLEYS TO FALL OFF THE FURTHEST AND BE THE LAST TO ENGAGE WITH THE INCREASING SOUTHERN SFC FLOW...WAITING UNTIL CLOSER TOWARDS DAWN TO BREAK THEIR TEMPERATURE FALL AND START TO RISE. MEANWHILE... RIDGES AND MORE OPEN LOCATIONS IN THE WEST WILL ONLY SLOWLY DROP OFF THROUGH THE FIRST PART OF THE NIGHT. EXPECT THE THICKENING CLOUDS AND INCREASING SOUTHERN WINDS TO ALLOW TEMPS TO CLIMB IN THE HOURS BEFORE DAWN MOST PLACES ALONG WITH RISING DEW POINTS. PCPN CHANCES SHOULD ARRIVE FROM NORTHWEST TO SOUTHEAST DURING THURSDAY MORNING WITH PLACES LIKELY WARMING QUICK ENOUGH TO PREVENT A MIX AT THE ONSET. THIS WILL STILL NEED TO BE WATCHED BUT AT THIS POINT IS NOT ENOUGH OF A CONCERN TO HIGHLIGHT IN THE GRIDS...ZONES...OR HWO. AS THE SFC LOW PASSES TO THE NORTH LATER THURSDAY...ITS FRONT WILL PUSH THROUGH A BAND OF RAIN FOR MOST OF THE AREA THAT AFTERNOON. COLDER AIR DOES FOLLOW ON WEST TO NORTHWEST WINDS FOR LATE IN THE AFTERNOON AND INTO THE EVENING THURSDAY. AS A RESULT...SOME SNOW MAY MIX IN WITH THE LINGERING RAIN BY 00Z FRIDAY IN THE NORTHWEST PARTS OF THE AREA. HAVE ADDED A MIX FOR THIS IN THE WX GRIDS TOWARDS THE END OF THE SHORT TERM PERIOD. AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR TEMPERATURES... DEW POINTS...AND WINDS THROUGH THIS EVENING AND THE SUPERBLEND THEREAFTER. DID MAKE SOME FAIRLY SUBSTANTIVE...TERRAIN BASED... ADJUSTMENTS TO HOURLY AND MINIMUM TEMPERATURES...AS WELL AS WINDS... TONIGHT AHEAD OF THE INBOUND FRONTAL SYSTEM. AS FOR POPS...ENDED UP CLOSE TO A COMBINATION OF THE MAV AND MET NUMBERS THROUGH THE DAY THURSDAY...THOUGH WITH ADDED TIMING DETAILS IN THE SPATIAL COVERAGE OF THE POP/WX GRIDS DURING THE AFTERNOON...IN PARTICULAR. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 425 AM EST WED JAN 28 2015 CLIPPER SYSTEM WILL BE EXITING TO THE EAST OF THE REGION AS WE MOVE INTO THURSDAY NIGHT. THERE WILL BE A CHANGE OVER FROM RAIN TO MIX AND THEN TO ALL SNOW. GIVEN LIMITED MOISTURE WITH THIS SYSTEM WOULD THINK ACCUMULATIONS WOULD BE QUITE LIGHT. DO KEEP THE MENTION OF SLIGHT CHANCES RIGHT ALONG THE RIDGES INTO EARLY FRIDAY GIVEN THE NW FLOW THAT SETUP ACROSS THE REGION THROUGH THAT PERIOD. THIS SURFACE LOW WILL RESTRENGTHEN ACROSS NEW ENGLAND STATES AS SURFACE HIGH DIVES ACROSS THE OHIO VALLEY THROUGH THE DAY FRIDAY. SKIES ARE EXPECTED TO CLEAR OUT THROUGH THE DAY AS HIGH PRESSURE AND DRIER AIR BUILD ACROSS EASTERN KY. THIS FRONT DOES BRING COLDER AIR MASS WITH TEMPS DROPPING INTO THE TEENS FRIDAY NIGHT. SATURDAY HIGH PRESSURE WILL SHIFT EAST AND THIS WILL BRING RETURN FLOW TO THE REGION. THIS WILL TRANSLATE TO REASONABLE REBOUND IN TEMPS WITH HIGHS REACHING INTO THE UPPER 30S TO LOWER 40S ACROSS MOST SPOTS. THEN ALL FOCUS SHIFTS TO DEVELOPING STORM SYSTEM ACROSS THE DESERT SW AND PLAINS SATURDAY. THIS DEVELOPING LOW PRESSURE SYSTEM COMBINED WITH UPPER LEVEL TROUGH THAT DEVELOPS ACROSS THE PLAINS WILL BE THE NEXT BIG WEATHER MAKER TO AFFECT EASTERN KY THIS COMING WEEKEND. THAT SAID THE FORECAST UNCERTAINTY FOR THIS STORM SYSTEM HAS BEEN QUITE NOTICEABLE FROM RUN TO RUN. PREVIOUS RUNS OF THE GFS IN REGARDS TO THIS SYSTEM SUGGESTED MORE PROGRESSIVE LOW PRESSURE SYSTEM...HOWEVER LATEST 00Z/28 IS A BIT MORE INLINE WITH THE LATEST 00Z/28 ECMWF. IT SHOULD ALSO BE NOTED THAT EVEN THE 00Z/28 GFS ENSEMBLE MEAN IS MORE PROGRESSIVE THAN THE OPERATIONAL SOLUTION AND LOOKING AT SOME OF THE PERTURBATIONS THE SURFACE LOW LOCATIONS VARY QUITE A BIT. THESE DIFFERING SOLUTIONS WILL HAVE IMPLICATIONS ON TIMING AND AMTS OF PRECIP. THIS TIMING WILL ALSO PLAY A BIG ROLL IN TIMING OF PRECIP CHANGE OVER TO SNOW SUNDAY NIGHT AND HOW MUCH SNOW WE ACTUALLY SEE. GIVEN UNCERTAINTY HAVE TRIED TO FOLLOW A MODEL BLEND APPROACH AT THIS POINT AND ALSO TRIED TO STAY IN REASONABLE COLLABORATION WITH SURROUNDING OFFICES. KEEP IN MIND RIGHT NOW MUCH OF THE QPF ASSOCIATED WITH THIS SYSTEM STILL LOOKS TO FALL IN THE FORM OF RAIN ON SUNDAY WHERE BETTER MOISTURE AND LIFT WILL TAKE PLACE DURING THAT PERIOD. GIVEN ALL THE UNCERTAINTY THINK THERE IS STILL POTENTIAL FOR ACCUMULATING SNOW SUNDAY NIGHT INTO MONDAY AND THIS WILL HAVE TO BE FINE TUNED IN SUBSEQUENT FORECAST UPDATES. MOVING INTO MONDAY WOULD EXPECT TEMPS TO GENERALLY DROP THROUGH THE DAY AND THE AMT OF DROP WILL DEPEND ON TIMING AND EVOLUTION OF THIS SYSTEM. THAT SAID THIS SYSTEM DOES LOOK TO USHER IN WELL BELOW NORMAL TEMPERATURES MONDAY NIGHT WITH LOWS DROPPING INTO THE TEENS AND EVEN SINGLE DIGITS IN SOME SPOTS. HIGH PRESSURE WILL MOVE EAST THROUGH THE DAY TUESDAY BRINGING SOME RETURN FLOW AND HIGHS GENERALLY IN THE LOW TO MID 30S SOUTH AND UPPER 20S TO LOWER 30S NORTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 140 PM EST WED JAN 28 2015 MOSTLY CLEAR SKIES AND FAIR WEATHER WILL GIVE WAY TO DETERIORATING CONDITIONS DURING THE LATTER THIRD OF THE FORECAST PERIOD. CLIPPER SYSTEM WILL SWEEP THROUGH THE OHIO VALLEY DURING THE DAY THURSDAY. RAIN SHOWERS WILL DEVELOP AHEAD OF THIS SYSTEM BEFORE CHANGING OVER TO SNOW SHOWERS BEHIND THE FRONT. APPEARS THE SFC COLD FRONTAL BOUNDARY WILL MOVE INTO OUR AREA...BLUEGRASS COUNTIES BY ABOUT MID AFTERNOON AND PUSH ACROSS THE REST OF EASTERN KENTUCKY THROUGH THE REMAINDER OF THE DAY. BROUGHT SHOWERS INTO THE FORECAST DURING THE MORNING HOURS THURSDAY. RAIN WILL CHANGE OVER TO SNOW THURSDAY EVENING/NIGHT AND LINGER INTO FRIDAY AS UPSLOPE SNOW SHOWERS GRADUALLY TAPER OFF. AS IS TYPICAL WITH CLIPPER SYSTEMS SFC WINDS WILL INCREASE CONSIDERABLY...TO BETWEEN 10 AND 15 KTS FROM THE SOUTHWEST AHEAD OF THE FRONT AND FROM THE WEST...NORTHWEST POST FRONTAL. WINDS WILL BE GUSTY AS WELL. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...RAY SHORT TERM...GREIF LONG TERM...DJ AVIATION...RAY

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