Area Forecast Discussion
Issued by NWS Jackson, KY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 190734 AFDJKL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON KY 334 AM EDT SUN APR 19 2015 .SHORT TERM...
-- Changed Discussion --
(TODAY THROUGH MONDAY) ISSUED AT 330 AM EDT SUN APR 19 2015 A CLOSED MID AND UPPER LEVEL LOW IS MOVING EAST INTO THE CENTRAL PLAINS STATES EARLY THIS MORNING WITH A TROUGH AXIS TRAILING INTO THE SOUTHERN PLAINS. AN UPPER LEVEL RIDGE AXIS EXTENDED NORTH FROM THE YUCATAN REGION NORTH INTO FL AND THEN FURTHER NORTH INTO THE GREAT LAKES REGION. FURTHER WEST ANOTHER RIDGE WAS IN PLACE OVER PARTS OF THE EASTERN PACIFIC. IN THE NORTHERN STREAM...A TROUGH WAS WORKING ACROSS THE CANADIAN PLAINS AND NEARING THE DAKOTAS. THERE WERE A FEW WEAKER SHORTWAVES MOVING WITHIN THE SOUTHWEST FLOW BETWEEN THE TROUGH AND THE RIDGING OVER THE SOUTHEASTERN STATES. IN ADVANCE OF THIS TROUGH...AND ASSOCIATED SFC LOW...MOISTURE WAS RETURNING NORTH AND NORTHEAST ACROSS THE SOUTHEASTERN STATES AND MS VALLEY REGION. AT THE SFC...PRESSURE PATTERN SOMEWHAT COMPLEX...WITH A NORTHERN STREAM COLD FRONT EXTENDING INTO THE NORTHERN PLAINS AND ROCKIES ASSOCIATED WITH THE NORTHERN STREAM SYSTEM. MEANWHILE...AN AREA OF LOW PRESSURE OVER THE CENTRAL PLAINS. FURTHER SOUTHEAST ANOTHER AREA OF LOW PRESSURE WAS OVER THE MS VALLEY REGION...ALONG A QUASI WARM FRONT THAT EXTENDED SOUTHEAST FROM ORGANIZING LOW PRESSURE OVER THE PLAINS. AS THE TROUGH WORKS FURTHER EAST AND A LEAST ONE SHORTWAVE MOVE NORTHEAST IN THE SOUTHWEST FLOW ALOFT...THE SFC WAVE SHOULD TRACK TO OR REORGANIZE NEAR THE CONFLUENCE OF THE OH AND MS RIVERS OVER THE NEXT SEVERAL HOURS. AS THIS OCCURS...THE WARM FRONT WILL APPROACH EASTERN KY...BEFORE MOVING INTO THE AREA OVER THE UPCOMING DAY. THE SFC WAVE WILL TRACK BY TO OUR NORTHWEST...WITH THE WARM FRONT LIFTING INTO WV AND OH BY MID TO LATE EVENING. AS THE ASSOCIATED SFC LOW MOVES INTO THE GREAT LAKES...THE TRAILING COLD FRONT SHOULD APPROACH THE REGION LATE SUNDAY TONIGHT AND CROSS THE AREA ON MONDAY. OVER THE NEXT SEVERAL HOURS...AS THE WARM FRONT LIFTS NORTH ACROSS THE TN VALLEY REGION AND INTO THE LOWER OH VALLEY AND APPALACHIAN REGION...A BAND OF SHOWERS WITH SOME POSSIBLE EMBEDDED THUNDERSTORMS IS EXPECTED TO WORK NORTH FROM THE SOUTHEASTERN STATES FROM NEARER TO DAWN AND LIFT ACROSS THE AREA THIS MORNING THROUGH MID AFTERNOON. IN ADVANCE OF THIS BAND OF SHOWERS...SOME MORE ISOLATED TO SCATTERED SHOWER ACTIVITY IS EXPECTED TO CONTINUE. SOME MID LEVEL DRYING IS ANTICIPATED IN THE WARM SECTOR DURING THE LATE MORNING AND AFTERNOON OVER CENTRAL KY AND MIDDLE TN. THIS SHOULD EXTEND INTO EASTERN KY AS WELL...STARTING EARLY THIS AFTERNOON IN THE FAR SOUTHWEST AND THE GRADUALLY SPREADING NORTH AND EVENTUALLY EAST. SOME DESTABILIZATION SHOULD ALSO OCCUR DURING THE AFTERNOON TO EARLY EVENING. THIS SHOULD LEAD TO MORE SCATTERED SHOWERS AND SOME THUNDERSTORMS...ESPECIALLY ACROSS THE WESTERN HALF OR SO OF THE AREA CLOSER TO THE ACTUAL SFC LOW TRACK. INSTABILITY IS NOT EXPECTED TO BE ALL THAT HIGH...WITH CAPE SOMEWHAT LIMITED. MODEL FORECAST SOUNDINGS INDICATE SBCAPE MAY REACH THE 1000 TO 1500 J/KG RANGE WITH SOMEWHAT STRONG FLOW ALOFT. THIS COULD SUPPORT SOME STRONGER THUNDERSTORMS WITH LOCALLY HEAVY RAIN...GUSTY WINDS AND POSSIBLY HAIL. A STRAY STORM OR TWO COULD BECOME SEVERE WITH STRONG WINDS THE PRIMARY THREAT...PENDING HOW UNSTABLE OR NOT THE REGION EVENTUALLY BECOMES. SPC HAS PLACED THE ENTIRE REGION IN A MARGINAL RISK FOR SEVERE THUNDERSTORM WITH THE HIGHER RISKS REMAINING WELL SOUTH AND SOUTHWEST OF EASTERN KY. EAST OF THE SFC LOW TRACK...THERE MAY BE A EVER SO SLIGHTLY HIGHER PROBABILITY FROM MIDDLE TN NORTH INTO CENTRAL AND NORTHERN KY. WITH THE LOSS OF DAYTIME HEATING AND WEAK MID LEVEL RIDGING PROGGED TO WORK ACROSS THE REGION OVERNIGHT...THERE SHOULD BE A LULL IN SHOWER AND ANY THUNDERSTORM ACTIVITY FROM LATE EVENING THROUGH MUCH OF SUNDAY NIGHT. THE CHANCES FOR ACTIVITY SHOULD INCREASE AGAIN TOWARD DAWN AND PEAK ON MONDAY AS THE COLD FRONT WORKS ACROSS THE AREA. IF SOME HEATING CAN OCCUR ACROSS EASTERN SECTIONS OF THE AREA IN ADVANCE OF THE FRONT...A COUPLE OF STRONG TO POSSIBLY SEVERE THUNDERSTORMS WOULD BE POSSIBLE WITH STRONG WINDS BEING THE MAIN THREAT. THE PRECIPITATION CHANCES WILL BEGIN TO DECREASE FROM WEST TO EAST BY EARLY ON MONDAY EVENING. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 334 AM EDT SUN APR 19 2015 PERIOD WILL BEGIN WITH RAIN SHOWERS MAINLY ACROSS THE SE PORTIONS...AS A COLD FRONT AND UPPER LEVEL SHORT WAVE PULL OUT OF THE REGION. HIGH PRESSURE WILL BUILD TO THE SOUTH OF THE REGION WITH COOLER AND DRIER AIR BUILDING INTO EASTERN KY. AFTER A WARM WEEKEND HIGHS ON TUESDAY WILL GENERALLY BE IN THE LOWER 60 UNDER SUNNY SKIES...WHICH WILL BE NEARLY 10 DEGREES BELOW NORMAL. THIS HIGH WILL MOVE EAST AND BRING SOME RETURN FLOW TO THE REGION TUESDAY NIGHT. HOWEVER TEMPS THROUGH THE PERIOD WILL STAY BELOW NORMAL. ALSO A WEAK FRONT AND WEAK UPPER LEVEL WAVE ROUNDING THE BASE OF THE UPPER LEVEL LOW CENTERED NEAR THE GREAT LAKES. THIS WILL BRING SLIGHT TO CHANCE POPS TUESDAY NIGHT INTO WEDNESDAY. HOWEVER THERE IS STILL SOME DIVERGENCE WITH THIS SETUP IN THE GUIDANCE...SO DID LEAN TOWARD THE BLEND MORE AT THIS POINT. THE ECMWF IS A BIT MORE INLINE WITH THE GFS THAN PREVIOUS RUNS FROM YESTERDAY...BUT REMAINS SLOWER THAN THE GFS IN THE LATEST RUNS. THE RAIN CHANCES DO WANE AS WE MOVE WEDNESDAY NIGHT INTO THURSDAY AS FRONT DROPS SOUTH OF THE REGION. THIS FRONT WILL BRING ANOTHER SHOT OF COLD AIR WITH 850 TEMPS IN THE 0 TO -4 RANGE THURSDAY NIGHT. THIS COUPLED WITH CLEARING SKIES COULD LEAD TO FROST DEVELOPMENT OVERNIGHT THURSDAY INTO FRIDAY MORNING ESPECIALLY ACROSS THE BLUEGRASS WHERE HIGH PLACEMENT IS BETTER. RIGHT NOW THE CONFIDENCE IS LOWER...SO WILL LEAVE OUT OF THE GRIDS FOR NOW. DID OPT TO LEAN TOWARD A RAW MODEL BLEND WHICH DID INTRODUCE SOME MID TO UPPER 30S ACROSS THE REGION. THIS HIGH PRESSURE IS EXPECTED MOVE EAST ACROSS THE REGION FRIDAY WITH INCREASING CLOUDS ACROSS THE CUMBERLAND VALLEY LATE FRIDAY AS NEXT SYSTEM APPROACHES. BOTH THE GFS AND ECMWF WANT TO KEEP A DEVELOPING SURFACE LOW TO THE SOUTH OF THE REGION. THIS WOULD SUPPRESS THE BETTER DYNAMICS WITH FORECAST SOUNDINGS SHOWING FAIRLY MEAGER INSTABILITY. DO INTRODUCE CHANCE POPS WITH BETTER CHANCES ACROSS THE SOUTHERN PORTIONS OF EASTERN KY. ALSO KEPT WITH PREVIOUS FORECAST IN TERMS OF NO THUNDER SATURDAY GIVEN THAT THE WARM SECTOR AND BETTER DYNAMICS WILL BE WELL SOUTH GIVEN LOW PLACEMENT.
-- End Changed Discussion --
&& .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 145 AM EDT SUN APR 19 2015 THE LOW AND MID LEVELS ARE BEGINNING TO SATURATE A BIT...BUT ONLY SOME VFR MID LEVEL CLOUDS ARE PRESENT ATTM. AS FURTHER SATURATION OCCURS OVERNIGHT...THESE SHOULD LOWER FURTHER TO NEAR THE MVFR/VFR BREAK. A BAND OF AREA OF SHOWERS SHOULD WORK INTO THE REGION...MAINLY AFTER 8Z TO 9Z...AND IF THESE ARE HEAVY ENOUGH VIS COULD BE REDUCED AT TIMES TO MVFR A SME AND ALSO EKQ PRIOR TO 12Z. THE RAIN IS EXPECTED TO EVENTUALLY BRING ENOUGH SATURATION FOR MVFR CEILINGS AND OR VISIBILITY FROM SW TO NE DURING THE 12Z TO 18Z PERIOD IN MOST PLACES. THE DETERIORATION SHOULD ARRIVE FIRST AT WESTERN LOCATIONS...WITH EASTERN LOCATIONS HOLDING OFF LONGER DUE TO DOWNSLOPE FLOW OFF THE HIGH TERRAIN TO OUR SE. SOME PERIODS OF IFR WILL BE POSSIBLE DURING SOME OF THE HEAVIEST RAIN. THUNDERSTORMS WITH GUSTY WINDS AND VIS TO IFR AND POSSIBLY BRIEFLY NEARING AIRPORT MINS WILL ALSO BE POSSIBLE...MAINLY 17Z AND LATER WEST OF INTERSTATE 75...WITH CHANCES POSSIBLY SPREADING NORTHEAST AS FAR AS SYM AND SJS BY 22Z OR SO. THE PRECIPITATION WILL BECOME LESS STEADY AND MORE SCATTERED IN NATURE FROM SW TO NE 17Z TO 22Z. CHANCES FOR PRECIP SHOULD DIMINISH FROM SW TO NORTHEAST 22Z TO 3Z IN SOME DRY SLOTTING BETWEEN THE WARM FRONT AND AN APPROACHING COLD FRONT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JP LONG TERM...DJ AVIATION...JP

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