Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 250615 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 215 AM EDT MON MAY 25 2015 .UPDATE... ISSUED AT 155 AM EDT MON MAY 25 2015 DID A QUICK UPDATE TO THE GRIDS PER THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 942 PM EDT SUN MAY 24 2015 CURRENT CONDITIONS ACROSS THE AREA FEATURE HIGH PRESSURE RETREATING TO THE EAST WITH MID AND UPPER LEVEL CLOUD COVER BEGINNING TO STREAM INTO CENTRAL KENTUCKY. GIVEN THE DRY AIR IN PLACE AND A SLOW RESPONSE TO THE MOIST SOUTHERLY FLOW...HAVE PUSHED THE ONSET OF PRECIP A LITTLE LATER IN THE MORNING. CLOUD COVER THOUGH HAS BEGUN TO MOVE INTO THE AREA IN EARNEST. SOME MID LEVEL CLOUD COVER WILL BEGIN TO MOVE OVER THE AREA THROUGH THE NIGHT AND WILL LIMIT THE RIDGE VALLEY SPLIT AS WELL AS ANY FOG IN MOST AREAS WITH THE EXCEPTION OF THE FAR EAST. ESPECIALLY WITH THE DRY AIR IN PLACE RIGHT NOT...FOG WILL BE FEW AND FAR IN BETWEEN WITH THE EXCEPTION OF SOME OF THE DEEPER RIVER VALLEYS. HAVE UPDATED THE FORECAST AND SENT OUT A NEW ZFP. UPDATE ISSUED AT 707 PM EDT SUN MAY 24 2015 UPDATED THE GRIDS TO INPUT THE LATEST OBS ACROSS THE AREA. THE FORECAST REMAINS ON TRACK AND PRECIP WILL NOT ENTER THE AREA TILL AFTER DAY BREAK. THE GRIDS HAVE BEEN SEND TO NDFD AND WEB SERVERS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 347 PM EDT SUN MAY 24 2015 UPPER LEVEL RIDGING HAS BEEN SHIFTING EASTWARD ACROSS THE OHIO RIVER VALLEY THROUGHOUT THE DAY AS BROAD TROUGHING AND AN UPPER LEVEL CLOSED LOW CONTINUE TO EXPAND ACROSS THE WESTERN HALF OF THE CONUS. MUCH OF WESTERN KY AND THE MISSISSIPPI RIVER VALLEY IS FINDING ITSELF WEDGED IN BETWEEN THE TWO PATTERNS WITH INCREASING PRESSURE GRADIENTS...RESULTING IN SOME BREEZY CONDITIONS ACROSS MUCH OF THE WESTERN AND CENTRAL PORTION OF THE STATE. HERE IN EASTERN KY...RIDGING IS STILL TRYING TO HOLD ON FOR THE NEXT FEW HOURS...BUT EXPECT HEIGHTS TO BE ON A SLOW DECLINE THROUGHOUT THE NIGHT AND INTO THE DAY TOMORROW AS THE UPPER LEVEL TROUGHING BEGINS TO CROSS OVER THE MISSISSIPPI RIVER VALLEY. A RIVER OF MOISTURE IS CURRENTLY STREAMING FROM THE GULF OF MEXICO UPWARDS THROUGH THE MISSISSIPPI RIVER VALLEY AND THEN WRAPPING ITSELF INTO THE STRONG LOW CURRENTLY COVER THE NORTHERN PLAINS...OR EASTWARD UP AND ALONG THE NORTHWARD EXTENT OF THE UPPER LEVEL RIDGE. THIS IS RESULTING IN A LARGE AMOUNT OF CLOUD COVER ACROSS THESE ABOVE MENTIONED AREAS. WHILE A FEW CLOUDS HAVE FOUND THEIR WAY INTO EASTERN KY...WE ARE GENERALLY MOSTLY SUNNY WITH STRONG BUT DRY SOUTHERLY FLOW AS OF 1930Z. AS THE RIDGE CONTINUES TO BREAK DOWN OVERNIGHT...AND THE UPPER LEVEL TROUGH NEARS CLOSER...EXPECT THESE CLOUDS TO EXPAND ACROSS KY...GENERALLY OF THE HIGH VARIETY...THOUGH SOME MID AND LOWER CLOUDS MAY BEGIN MOVING IN AS EARLY AS TOMORROW MORNING. ALONG WITH THESE CLOUDS...THERE WILL CONTINUE TO BE AN UPTICK IN MOISTURE AND TEMPERATURES FOR THE DAY TOMORROW. A SHORTWAVE MOVING UP AND ALONG THE EXITING RIDGE WILL PROVIDE A STRONG ENOUGH TRIGGER TO ALLOW SCATTERED SHOWERS AND THUNDERSTORMS TO BEGIN DEVELOPING TOMORROW DURING THE DAY...INCREASING IN COVERAGE AND INTENSITY AS WE HEAD INTO THE AFTERNOON HOURS WITH PEAK HEATING AND INSTABILITY. AS THE RIDGE CONTINUES TO BREAK DOWN OVER THE EAST...EXPECT THIS CONVECTION TO SPREAD ACROSS THE ENTIRE CWA DURING THE DAY. LOSS OF DAYTIME HEATING AND FUEL WILL ALLOW DIMINISHED COVERAGE OVERNIGHT MONDAY NIGHT...BUT CONTINUED LOWERING HEIGHTS AND MORE SHORTWAVE INFLUENCE WILL ALLOW FOR SHOWERS AND THUNDERSTORMS TO QUICKLY BEGIN RAMPING UP AGAIN BY TUESDAY MORNING. FOR TEMPERATURES...STRONG SOUTHERLY FLOW ACROSS THE REGION ALLOWED TEMPS TO MAKE IT INTO THE LOW AND MID 80S THIS AFTERNOON. WITH INCREASING MOISTURE...CONTINUED STRONG SOUTHERLY FLOW...AND THE POTENTIAL FOR AN UPTICK IN CLOUD COVER OVERNIGHT...EXPECT OVERNIGHT TEMPERATURES TO BE MUCH WARMER THAN NIGHTS PREVIOUS. GENERALLY UPPER 50S TO MID 60S ARE EXPECTED. WE COULD STILL SEE SOME DECENT RIDGE TO VALLEY TEMPERATURE DIFFERENCES...BUT EXPECT THAT GIVEN THE ABOVE MENTIONED FACTORS...THE BEST POTENTIAL FOR THIS TO OCCUR WILL BE IN THE TERRAIN ACROSS THE FAR EASTERN PORTION OF THE CWA...AWAY FROM THE BEST CLOUD COVER AND WIND INFLUENCES. TEMPERATURES COULD FALL AS LOW AS THE LOW TO MID 50S IN SOME OF THESE VALLEYS OVERNIGHT. BY TOMORROW...TWO THINGS WILL COME INTO PLAY. FIRST...STRONGER SOUTHERLY FLOW ACROSS THE REGION WHICH WOULD PROMOTE A CONTINUED WARM UP ACROSS THE REGION. HOWEVER...THIS MAY BE OFFSET BY ENCROACHING CLOUD COVER AND THE POSSIBILITY FOR RAIN. AS SUCH...EXPECT SIMILAR TEMPS OVERALL TO THAT OF TODAY...GENERALLY IN THE LOW TO MID 80S. TEMPERATURES WILL OBVIOUSLY LIKELY FLUCTUATE AS RAIN SHOWERS/THUNDERSTORMS PASS OVER. FINALLY...BY TOMORROW NIGHT...THE INCREASING CLOUDS AND MOISTURE WILL WORK TO ALLEVIATE THE LARGE RIDGE VALLEY DIFFERENCES...AND WILL KEEP TEMPS GENERALLY MILD ACROSS THE REGION...IN THE LOW TO MID 60S FOR OVERNIGHT LOWS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 453 PM EDT SUN MAY 24 2015 A WARM AND RELATIVELY HUMID AIR MASS WILL BE IN PLACE AS THE PERIOD STARTS...AS HIGH PRESSURE AT THE SURFACE AND ALOFT OFF THE EAST COAST TRANSPORTS DEEP MOISTURE NORTH AND NORTHEAST OVER THE FORECAST AREA. A LARGE CHUNK OF THE CURRENT SOUTHWEST CONUS LARGE SCALE TROUGH WILL LIFT OUT TO THE NORTHEAST AS A SHORTWAVE TROUGH... CROSSING THE MIDWEST ON TUESDAY. THIS SHOULD LEND UPPER SUPPORT FOR PRECIP LOCALLY. SUFFICIENT SHEAR WILL BE PRESENT FOR ORGANIZED CONVECTION ON TUESDAY. THE DEGREE OF INSTABILITY WHICH WILL DEVELOP REMAINS IN QUESTION. IF THERE IS TOO MUCH ONGOING CLOUD COVER AND PRECIP DURING THE DAY TUESDAY...IT WILL LIMIT OUR DESTABILIZATION AND THE THREAT OF STRONG CONVECTION. BUT...IF ENOUGH HEATING OCCURS...THERE IS A CONCERN FOR SEVERE WEATHER. AFTER THE TUESDAY SYSTEM PASSES...BROAD FLOW OUT OF THE WEST SOUTHWEST WILL PERSIST FROM HERE NORTHWESTWARD. MODELS SHOW ANOTHER SHORTWAVE TROUGH APPROACHING IN THE FLOW ALOFT LATE WEDNESDAY AND WEDNESDAY EVENING...JUSTIFYING ANOTHER PERIOD OF ELEVATED POP. ONCE THIS PASSES...FLOW ALOFT RELAXES AND GEOPOTENTIAL HEIGHTS RISE...SUPPORTING A LOWER POP LATE IN THE WEEK. HOWEVER...THERE WILL BE NO SUBSTANTIAL CHANGE IN SURFACE AIR MASS...AND WITH WARM AND MOIST AIR LINGERING...THE POP WILL NOT GO AWAY ENTIRELY. FINALLY...ANOTHER SYSTEM COULD AFFECT THE REGION OVER THE WEEKEND. THE GFS AND ECMWF DO START TO SHOW MORE PATTERN DIFFERENCES BY THEN...BUT BOTH SHOW SOME SEMBLANCE OF THE SYSTEM AFFECTING US. THE GFS HAS A COLD FRONT DROPPING IN FROM THE NORTH FASTER THAN THE ECMWF...BUT BOTH EVENTUALLY SHOW THE FRONT IN OUR VICINITY BY SUNDAY...WITH OUR AREA POSITIONED ON THE EASTERN SIDE OF AN UPPER LEVEL TROUGH. WITH DISAGREEMENT FOR SATURDAY...HAVE STAYED WITH FAIRLY LOW POPS...BUT WENT UP TO HIGH CHANCE FOR SUNDAY WHEN BOTH MODELS SHOW A MORE FAVORABLE ENVIRONMENT. THROUGHOUT THE LONG TERM PERIOD...DIURNAL HEATING WILL LIKELY PLAY A ROLE IN TIMING OF PRECIP COVERAGE ON THE LARGE SCALE...AND HAVE TIMED PEAK POP LOCALLY DURING THE LATE AFTERNOON AND EVENING HOURS EACH DAY. THIS MAY BE ABLE TO BE FURTHER REFINED AS TIME PASSES AND CONFIDENCE GROWS IN HANDLING OF SMALLER SCALE FEATURES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 215 AM EDT MON MAY 25 2015 EXPECT VFR CONDITIONS TO BE IN PLACE THROUGH AT LEAST THE MORNING HOURS ON MONDAY. HOWEVER...CEILINGS WILL DEVELOP AND BEGIN TO LOWER DURING THE DAY AS SHOWERS AND THUNDERSTORMS TAKE SHAPE OVER CENTRAL KENTUCKY AND MOVE IN FROM THE WEST. THIS WILL BRING THE POTENTIAL FOR SOME MVFR AND BRIEF IFR CIGS/VIS INTO THE AREA IN THE AFTERNOON WITH ANY STORM. THESE CONDITIONS WILL CONTINUE INTO THE EVENING WITH A DIMINISHING TREND TO COVERAGE AND SOME IMPROVEMENT TO THE CIGS. WINDS WILL BE LIGHT THROUGH THE NIGHT BUT INCREASE FROM THE SOUTHWEST THROUGH THE DAY REACHING 10 TO 20 KTS FOR A TIME IN THE AFTERNOON AMID THE SHOWERS AND STORMS. LOOK FOR THE WINDS TO SETTLE DURING THE EVENING FOLLOWING SUNSET. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JMW LONG TERM...HAL AVIATION...GREIF

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