RSS FeedsIssued by NWS Paducah, KY
000 FXUS63 KPAH 230959 AFDPAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 359 AM CST MON NOV 23 2009 .DISCUSSION... WITH RESPECT TO CURRENT WEATHER...THE DRIER AND COOLER AIR THAT WAS ADVECTED INTO THE WFO PAH FORECAST AREA AHEAD OF THE PASSAGE OF THE UPPER LOW FROM THE LOWER MS VALLEY TO THE TN VALLEY ON SUNDAY HAS CEASED AND HAS BEEN REPLACED BY DECENT WARM AIR ADVECTION. A GOOD STRATUS DECK...INDICATIVE THE DECENT LOW LEVEL MOISTURE RETURN...WAS COVERING THE SOUTHERN 1/3RD OF THE WFO PAH FORECAST AREA AS OF 09Z. THE KPAH VAD WIND PROFILE SHOWS THAT THE WARM/MOIST AIR HAS WORKED DOWN AS FAR AS 925 MB IN EXTREME SOUTHERN IL/WESTERN KY...WITH A GREATER DEPTH OF WARM MOIST AIR FROM SURFACE TO NEARLY 700 MB. THEREFORE...UNTIL THERE IS SUFFICIENT MIXING THROUGH THE WARM LATER THIS AFTERNOON...MOSTLY CLOUDY TO CLOUDY SKIES WILL BE THE RULE FOR AT LEAST THE SOUTHERN 2/3RDS OF THE WFO PAH FORECAST AREA. THE BIGGEST CONCERN FOR THIS MORNING...BASED ON RADAR AND SOME SURFACE OBSERVATIONAL TRENDS...IS THE POTENTIAL THAT THE LIFT ASSOCIATED WITH SUCH A WARM AIR ADVECTION ZONE OVER SOUTHEAST MO...SOUTHWEST IL AND THE PURCHASE AREA OF WEST KENTUCKY MAY PRODUCE SOME LIGHT PRECIPITATION. EARLIER MODEL RUNS FROM THE NAM-WRF/SREF AND ECMWF HAVE BEEN HINTING AT THIS POSSIBILITY. IN ANY CASE...I MAY NEED TO ADDRESS THIS MATTER BEFORE SENDING OUT THE CURRENT FORECAST PACKAGE. UNTIL THE WFO PAH FORECAST AREA IS FULLY INTO THE WARM SECTOR OF THE APPROACHING LOW OVER KS/NORTHWEST MO THIS AFTERNOON AND TONIGHT...VARIABLE CLOUDINESS WILL STILL BE A PROBLEM. THERE IS SOME POTENTIAL FOR FOG DEVELOPMENT OVER SOUTHWEST INDIANA...SOUTHEAST ILLINOIS...NORTHWEST KENTUCKY LATE TONIGHT...BUT I SUSPECT THAT CLOUD COVER WILL BE THE DOMINANT FEATURE OVERNIGHT INTO TUESDAY MORNING. THE GFS/SREF/ECMWF ARE SLIGHTLY SLOWER IN THE EASTWARD TRANSLATION OF THE UPPER FROM KS INTO NORTHERN MO BY LATE TUESDAY AFTERNOON. ALTHOUGH PROGRESSIVE...SENSIBLE WEATHER ASSOCIATED WITH THE VERTICALLY STACKED LOW WILL REMAIN CLOSE TO THE SYSTEM. THEREFORE...I HAVE CHOSEN TO SLOW THE ONSET OF MEASURABLE PRECIPITATION WITH THE NEXT SYSTEM UNTIL TUESDAY MORNING. WITH RESPECT TO ANY MIXED PRECIPITATION ALONG THE SOUTHERN EDGE OF THE EVOLVING GREAT LAKES CLOSED LOW/CYCLONIC CIRCULATION...I HAVE KEPT PRECIPITATION MOSTLY IN THE FORM OF RAIN OVER SOUTHWEST INDIANA AND THE EASTERN PENNYRILE REGION OF WESTERN KY...EXCEPT FOR THURSDAY MORNING AND AGAIN THURSDAY NIGHT...WHEN THERMAL PROFILES ALOFT SUPPORT SUFFICIENT COOLING IN THE CRYSTALLIZATION ZONE FOR A MIX OF RAIN OR SNOW. GIVEN THE WARM SURFACE TEMPERATURES...NO ACCUMULATION OF SNOW IS EXPECTED. MAX/MIN TEMPERATURES THROUGH FRIDAY WERE ADJUSTED USING A BLEND OF SPATIALLY ADJUSTED GFS/ECMWF THERMAL FIELDS. DEWPOINTS AND WINDS THROUGH THURSDAY WERE ADJUSTED UNDER A GREATER INFLUENCE OF NAM- WRF/RUC MASS/WIND FIELDS. && .AVIATION... LOW CLOUDS ARE CURRENTLY INVADING OUR AREA FROM THE SOUTH. VFR CONDITIONS WILL PERSIST AT KEVV/KOWB FOR SEVERAL MORE HOURS...BUT AT KPAH AND KCGI...WE ARE AT OR VERY NEAR MVFR CIGS ATTM. THESE MVFR CIGS WILL REMAIN WITH US FOR THE REMAINDER OF THE DAY...MAYBE SCATTERING OUT BY AFTERNOON...BUT DROPPING DOWN TO MVFR BEFORE SUNSET. IN ADDITION TO THE MVFR CIGS...WE COULD SEE VSBYS DROP DOWN INTO THE MVFR CATEGORY EARLY THIS MORNING. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ AVIATION/FIRE WEATHER...CW SHORT/LONG TERM PUBLIC...SMITH
