Area Forecast Discussion
Issued by NWS Jackson, KY

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000 FXUS63 KJKL 240629 AAA AFDJKL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON KY 229 AM EDT SUN MAY 24 2015 .UPDATE...
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ISSUED AT 200 AM EDT SUN MAY 24 2015 THE CURRENT FORECAST IS ON TRACK FOR THE REST OF THE NIGHT. FOR THIS UPDATE HAVE JUST TOUCHED UP THE SKY/T/TD GRIDS PER THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 738 PM EDT SAT MAY 23 2015 UPDATED TO REFLECT MORE CLEARING THROUGH THE OVERNIGHT HOURS AS HIGH CLOUDS WILL BE MORE LIMITED TONIGHT. HOWEVER...NO CHANGES MADE TO TEMPERATURES YET AS ITS TOO EARLY TO SEE HOW QUICKLY TEMPERATURES WILL DIVE THIS EVENING. THUS...OVERALL FORECAST REMAINS UNCHANGED AS OF RIGHT NOW.
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&& .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 303 PM EDT SAT MAY 23 2015 STRONG UPPER LEVEL CLOSED LOW OVER SOUTHEAST CANADA...AS WELL AS A CLOSED LOW OVER THE AMERICAN SOUTHWESTERN STATES...HAS LED TO A SLIGHT RIDGING PATTERN ACROSS THE PLAINS...MISSISSIPPI RIVER VALLEY...AND INTO THE OHIO RIVER VALLEY. SEVERAL WAVES OF ENERGY ARE RIDING UP AND ALONG THIS BROAD RIDGING PATTERN...BUT SHOULD CONTINUE TO DIMINISH AND REMAIN NEARLY STATIONARY THROUGH TOMORROW AS BOTH UPPER LEVEL LOWS GAIN STRENGTH AND MOVE EASTWARD. THIS WILL AMPLIFY THE RIDGING ACROSS THE OHIO RIVER VALLEY AND ESSENTIALLY PREVENT ANY SHORTWAVES FROM MAKING IT INTO THE REGION. AS SUCH...A VAST AMOUNT OF CLOUD COVER IS PRESENT ON SATELLITE WEST OF THE MISSISSIPPI RIVER DUE TO THESE DISTURBANCES. SOME OF THIS CLOUD COVER HAS BEEN TRANSPORTED EASTWARD AND ACROSS THE STATE OF KY...INCLUDING THE JKL CWA. HOWEVER...EXPECT THAT ALL CLOUDS SHOULD REMAIN OF THE HIGH VARIETY...GENERALLY OVER 1000FT. THE ONLY IMPACT THIS SCT CLOUD COVER WILL HAVE IS TO PREVENT SUCH A LARGE RIDGE VALLEY SPLIT IN TEMPERATURES OVERNIGHT TONIGHT. EXPECT THE STRONG UPPER LEVEL LOW OVER THE SW CONUS TO REACH THE WESTERN PLAIN STATES BY SUNDAY MORNING...CONTINUING TO SHIFT NORTHEAST...REACHING THE DAKOTAS BY 12Z MONDAY MORNING. DURING THIS TIME...THE ASSOCIATED UPPER LEVEL TROUGHING WILL EXPAND EASTWARD AS WELL...PUSHING THE STRONG RIDGE OVER THE OHIO RIVER VALLEY EASTWARD. SOME SHORTWAVE ENERGY WILL BEGIN IMPACTING MUCH OF THE MISSISSIPPI RIVER VALLEY DURING THIS TIME...BUT RIDGING SHOULD REMAIN INTACT ENOUGH ACROSS THE EASTERN PORTION OF THE STATE THAT JKL SHOULD REMAIN DRY AND GENERALLY IMPACT FREE THROUGH 12Z. THE ONLY EXCEPTION WILL BE AN INCREASE IN CLOUD COVER...MAINLY ACROSS THE WESTERN CWA ...WITH POPS EXPECTED TO MOVE IN DURING THE DAY MONDAY...JUST AFTER THE END OF THE SHORT TERM. WITH A CONTINUED FLUX OF S TO SW WINDS AT THE SURFACE...AND WESTERLY WINDS ALOFT...EXPECT TEMPS TO CONTINUE TO RISE THROUGHOUT THE SHORT TERM. HUMIDITY LEVELS WILL ALSO BE ON A SLOW UPTICK AS WELL. HIGH TEMPS TOMORROW ARE EXPECTED TO TOP OUT IN THE LOW TO MID 80S ACROSS THE REGION COMPARED TO THE UPPER 70S/LOW 80S OF TODAY. MEANWHILE...ANY INCOMING CLOUD COVER WILL PROHIBIT SUCH STRONG RIDGE VALLEY SPLITS OVER THE NEXT TWO NIGHTS COMPARED TO THAT SEEN IN PREVIOUS NIGHTS. THIS WILL ESPECIALLY BE THE CASE SUNDAY NIGHT. GENERALLY LOW TO MID 50S ARE EXPECTED TONIGHT...WITH A FEW VALLEY LOCATIONS POSSIBLY BOTTOMING OUT IN THE UPPER 40S. HOWEVER...BY TOMORROW NIGHT...OVERNIGHT TEMPS WILL IMPROVE CONSIDERABLY TO THE UPPER 50S TO LOW 60S. ALL MODELS SEEM TO HAVE A GOOD HANDLE ON THE SYNOPTIC FEATURES AND SENSIBLE WEATHER DURING THE SHORT TERM. GENERALLY STUCK WITH A BLEND OF NEAR TERM MODELS...WITH SOME MANUAL EDITING TO PRODUCE THE DESIRED RIDGE VALLEY SPLITS...AS WELL AS OVERNIGHT VALLEY REDUCTIONS IN WIND. NO EXTREME OUTLIERS IN MODELS WERE NOTICED. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 455 PM EDT SAT MAY 23 2015 LOW LEVEL MOISTURE OFF THE GULF OF MEXICO SHOULD MAKE A RETURN AT THE START OF THE PERIOD. UPPER LEVEL RIDGING OVER THE SOUTHEAST CONUS WILL ALSO WEAKEN AND MOVE EASTWARD EARLY IN THE PERIOD. THIS WILL ALLOW THE WESTERLIES AND THEIR EMBEDDED DISTURBANCES TO MOVES CLOSER. THE COMBINATION OF THE ONSET OF MOISTURE/INSTABILITY AND AN UPPER LEVEL ENVIRONMENT MORE CONDUCIVE FOR CONVECTION WILL RESULT IN THE RETURN OF SHOWERS AND THUNDERSTORMS. FEATURES ALOFT FOR OUR LOCAL AREA ARE STILL EXPECTED TO BE RATHER WEAK...AND A SIGNIFICANT DIURNAL TREND IS EXPECTED FOR PRECIP...WITH A PEAK IN POP DURING THE AFTERNOON AND EVENING HOURS EACH DAY. MODELS DO SHOW A SHORTWAVE TROUGH APPROACHING ON TUESDAY AND PASSING TO OUR NORTHWEST ON WEDNESDAY. THE HIGHEST POPS OF THE WEEK WILL BE EXPECTED WITH THIS FEATURE. ONCE THIS PASSES...OUR FLOW ALOFT BECOMES MUCH WEAKER...WITH A LACK OF DISTURBANCES. HOWEVER...NO SIGNIFICANT CHANGE IN SURFACE AIR MASS SHOULD OCCUR. THIS SCENARIO WOULD TEND TO BRING AT LEAST A REDUCTION IN PRECIP COVERAGE...BUT MAY NOT ELIMINATE IT ENTIRELY. BY SATURDAY...THE GFS SHOWS ANOTHER COLD FRONT DROPPING IN FROM THE NORTH...IN RESPONSE TO A STRONG UPPER LEVEL LOW AND TROUGH PIVOTING THROUGH SOUTHEAST CANADA. THE ECMWF SHOWS THESE FEATURES AS WELL...BUT IS NOT AS AMPLIFIED WITH EXTENSION OF THE PATTERN OVER THE CONUS...AND AS A RESULT KEEPS THE SURFACE BOUNDARY FURTHER NORTH. CONFIDENCE IS LOW IN THE PROGRESS OF THIS FRONT...AND HAVE HELD POPS FAIRLY LOW YET ON SATURDAY. && .AVIATION...
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(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 230 AM EDT SUN MAY 24 2015 VFR CONDITIONS WILL CONTINUE AT THE TAF SITES OVER THE NEXT 24 TO 36 HOURS. SOME PATCHY RIVER VALLEY FOG IS EXPECTED AGAIN DURING THE REMAINDER OF THE NIGHT...BUT ONCE AGAIN SHOULD NOT IMPACT TAF SITES. OTHERWISE...EXPECT SOME THIN HIGH CLOUDS TO DRIFT ACROSS THE AREA FROM TIME TO TIME. SOUTH WINDS WILL RAMP UP ACROSS CENTRAL KENTUCKY ON SUNDAY...SO HAVE INTRODUCED SOME MORE MODERATE WINDS INTO THE SME/LOZ/SYM/SJS TAFS BEFORE TAPERING THEM OFF AFTER 00Z MONDAY.
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&& .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JMW LONG TERM...HAL AVIATION...KAS/GREIF

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