Area Forecast Discussion
Issued by NWS Jackson, KY

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS63 KJKL 292058 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 358 PM EST THU JAN 29 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 358 PM EST THU JAN 29 2015 A SURFACE COLD FRONT WAS ENTERING THE JKL FORECAST AREA FROM THE NW AT MID AFTERNOON. AS IS OFTEN THE CASE...COLD AIR ADVECTION WILL LEAD TO STEEP LOW LEVEL LAPSE RATES...AND WHEN COMBINED WITH UPSLOPE FLOW...SHALLOW CONVECTIVE PRECIP SHOULD DEVELOP. IT WILL BE FURTHER AIDED BY THE SUPPORT OF THE MID/UPPER LEVEL TROUGH AXIS PASSING OVER TONIGHT AND EARLY FRIDAY. INITIALLY...THE TEMPERATURE PROFILE SUPPORTS PRECIP IN THE FORM OF RAIN THIS EVENING. AS THE COLUMN COOLS...SURFACE TEMPS WILL COOL ENOUGH TO ALLOW SNOW...AND THE UPPER PART OF THE MOISTURE COLUMN WILL EVENTUALLY REACH -10C AND COLDER...AND PRECIP WILL CHANGE TO SNOW. THE PRECIP AMOUNTS WILL BE LIGHT...BUT THE PROBABILITY IS FAIRLY HIGH. SNOWFALL WILL GENERALLY BE A HALF INCH OR LESS...BUT SOME AMOUNTS OF AROUND AN INCH MAY OCCUR AT HIGHER ELEVATIONS IN THE SOUTHEAST. THE LAST OF THE SNOW SHOWERS WILL TAPER OFF DURING THE DAY FRIDAY AS HIGH PRESSURE BUILDS IN AND UPSLOPE FLOW IS LOST. MOSTLY CLEAR SKIES ARE EXPECTED AS THE SURFACE HIGH PASSES OVER ON FRIDAY NIGHT. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 358 PM EST THU JAN 29 2015 THIS PERIOD STARTS OUT QUIET WITH HIGH PRESSURE OVERHEAD AND TEMPERATURES NEAR 40 DEGREES...THANKS IN PART TO SOUTHWESTERLY WINDS. SKIES WILL BE MOSTLY CLEAR IN THE MORNING WITH INCREASING CLOUDS IN THE AFTERNOON AS THE NEXT STORM SYSTEM APPROACHES THE REGION. THERE IS STILL A LOT OF UNCERTAINTY WITH THIS LATE WEEKEND SYSTEM DUE TO THE MODEL RUN TO RUN DIFFERENCES. BOTH THE ECMWF/GFS MODELS BRING SOUTHERN STREAM ENERGY FROM THE SOUTHWESTERN US LOW AND TRY TO PHASE IT WITH THE NORTHERN STREAM ENERGY AS IT CROSSES THE TENNESSEE VALLEY. HOWEVER... THE TRACK AND STRENGTH OF THE SFC LOW THAT DEVELOPS IN THE MODELS IS WHERE THERE ARE SUBSTANTIAL RUN TO RUN DIFFERENCES....ESPECIALLY WITH THE LATEST 12Z/29 GFS RUN WHICH DEEPENS THE SFC LOW AND TAKES IT UP ACROSS MASSACHUSETTS. ONE THING THE MODELS DO HAVE IN COMMON IS THE AMOUNT OF QPF THEY SHOW. ANOTHER QUESTION THAT REMAINS IS HOW MUCH COLD AIR STAYS IN PLACE AND THIS WILL HEAVILY DEPEND ON THE TRACK OF THE SFC LOW. THAT BEING SAID... HAVE LEANED A BIT TOWARD A COLDER SOLUTION ON SUNDAY. MODEL SOUNDINGS HAD MOST OF THE MOIST COLUMN BELOW ZERO WITH SFC TEMPS JUST ABOVE FREEZING UNTIL LATE SUNDAY NIGHT. OVERALL CONFIDENCE IN THIS SYSTEM REMAINS LOW. THOUGH...STILL BELIEVE THERE IS A REASONABLE CHANCE FOR MEASURABLE SNOW SUNDAY INTO MONDAY. AS THE SYSTEM DEPARTS HIGH PRESSURE ONCE AGAIN BUILDS INTO THE REGION...ALONG WITH A COLD AIR MASS. THIS SHOULD ALLOW TEMPERATURES TO GENERALLY BE FALLING THROUGHOUT THE DAY ON MONDAY. LOWS MONDAY NIGHT COULD REACH THE SINGLE DIGITS IN SPOTS BUT SHOULD MAINLY BE IN THE LOW TO MID TEENS. TEMPERATURES SHOULD REBOUND ON TUESDAY INTO THE MID TO UPPER 30S IN RESPONSE TO SOUTHERLY FLOW FROM THE GULF USHERING IN WARMER AIR. WEDNESDAY ANOTHER SYSTEM MOVES INTO KENTUCKY BRINGING ANOTHER CHANCE FOR A MIXED PRECIP EVENT ENDING ON THURSDAY. AN ARCTIC AIR MASS ADVECTS IN BEHIND IT... DROPPING TEMPS ONCE AGAIN INTO THE LOW TEENS AND SINGLE DIGITS. FRIDAY WILL BE A CHILLY BUT QUIET DAY WITH HIGHS WELL BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 211 PM EST THU JAN 29 2015 VFR PREVAILED AT THE START OF THE PERIOD...BUT LOW VFR CEILINGS WERE PROGRESSING SE ACROSS THE REGION AFTER A PERIOD OF CLEARING. THE CEILINGS ON THE WAY IN WILL GET PROGRESSIVELY LOWER WITH TIME. BY 00Z MVFR CAN BE EXPECTED AREA WIDE...WITH IFR BEGINNING TO SHOW UP. SCATTERED LIGHT RAIN SHOWERS WILL ALSO DEVELOP DURING THE AFTERNOON. MOST AREAS WILL DEGRADE TO IFR TONIGHT...AND REMAINING RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS. THE SNOW SHOWERS WILL TAPER OFF AND CEILINGS WILL START TO BREAK UP DURING THE DAY ON FRIDAY. WINDS WILL GUST IN THE NEIGHBORHOOD OF 15-20 KTS THROUGH THE PERIOD...INITIALLY FROM THE SW AND THEN SHIFTING TO THE WEST TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HAL LONG TERM...JVM AVIATION...HAL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.