Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 261445 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 1045 AM EDT TUE MAY 26 2015 .SYNOPSIS... WARM AND HUMID AIR WILL REMAIN IN PLACE OVER THE MIDDLE OHIO VALLEY THROUGH THE REST OF THE WEEK. AS UPPER LEVEL DISTURBANCES MOVE THROUGH THE AREA...THERE WILL BE OCCASIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS TODAY AND WEDNESDAY...AND THEN AGAIN OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... SKIES ARE CLEARING ACROSS THE REGION WHICH WILL ALLOW FOR A WINDOW OF HEATING AND DESTABILIZATION. HOWEVER POOR MID LEVEL LAPSE RATES AS SEEN ON THE 12Z SOUNDING SHOULD BE A LIMITING FACTOR IN HOW MUCH INSTABILITY DEVELOPS. STILL SOME QUESTION OF CONVECTIVE TIMING ALTHOUGH RECENT RUNS OF THE HRRR AND RAP ARE IN AGREEMENT IN DEVELOPING STORMS MOVING INTO THE WESTERN AND SOUTHERN PARTS OF THE FORECAST AREA AROUND OR SHORTLY AFTER 18Z AND THEN TRACKING ACROSS THE REGION THROUGH THE AFTERNOON AND EARLY EVENING. THIS IS BROADLY IN AGREEMENT WITH THE NSSL WRF SOLUTION. IT DOES APPEAR THAT ADDITIONAL SCATTERED CONVECTION MAY CONTINUE AFTER 00Z WITH THE BETTER CHANCE SEEMINGLY IN THE SOUTHEAST COUNTIES ALTHOUGH THIS MORE FAVORABLE LOCATION MAY DIFFER DEPENDING ON HOW EARLIER STORMS EVOLVE. FORECAST INSTABILITY AND SHEAR SEEM ON THE MARGINAL SIDE AND THE JUXTAPOSITION OF THESE TWO FACTORS DOES NOT APPEAR PARTICULARLY IN SYNC. NONETHELESS CANNOT RULE OUT A FEW SEVERE STORMS THIS AFTERNOON AND EARLY EVENING WITH DAMAGING STRAIGHT LINE WINDS THE MAIN THREAT. MAIN UPDATE WAS ADJUSTING TIMING OF POPS AND BUMPING UP WINDS SLIGHTLY. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... ON WEDNESDAY...AN UPPER TROUGH WILL BE MOVING EAST INTO THE GREAT LAKES REGION. INITIALLY FAIRLY WELL-DEFINED OVER THE UPPER MISSISSIPPI VALLEY (AND HELPING TO DRIVE THE MORE ACTIVE WEATHER ON TUESDAY)...THIS TROUGH WILL BE WASHING OUT AS IT PROGRESSES AHEAD. STILL...IT WILL LEAVE THE MIDDLE OHIO VALLEY IN A FAVORABLE AREA OF LIFT...THOUGH SURFACE FEATURES WILL BE LACKING AND THUS FORCING MAY NOT BE PARTICULARLY WELL FOCUSED. WHILE SHEAR WILL CONTINUE TO BE MODEST...INSTABILITY SHOULD ACTUALLY INCREASE SLIGHTLY FROM TUESDAY...WITH MLCAPE VALUES PERHAPS APPROACHING 2000 J/KG IN THE SOUTHWESTERN SECTIONS OF THE CWA (AND UP TO 1500 J/KG ELSEWHERE). THUS...AMONG THE SCATTERED THUNDERSTORMS THAT DEVELOP...A FEW STRONG TO POSSIBLY SEVERE STORMS MAY OCCUR. AS THE AFOREMENTIONED TROUGH CONTINUES TO WEAKEN AND MOVE EAST...THE ILN FORECAST AREA WILL END UP IN A REGIME OF BUILDING RIDGING ALOFT...AND A WEAK/NEBULOUS AREA OF HIGH PRESSURE AT THE SURFACE. BY THURSDAY...THIS WILL BEGIN TO LIMIT THE CHANCES FOR CONVECTION...WITH DIURNAL DEVELOPMENT ONLY APPEARING TO BE A POSSIBILITY IN THE SOUTHERN HALF OF THE FORECAST AREA. FRIDAY WILL LIKELY BEGIN DRY AS WELL...THOUGH THE FLOW WILL BE SWITCHING BACK TO THE SOUTH IN THE SECOND HALF OF THE DAY...LEAVING A POSSIBILITY FOR SOME DEVELOPMENT (ESPECIALLY FOR THE SOUTHWESTERN HALF OF THE FORECAST AREA) BY LATE AFTERNOON AND EVENING. TO NOTE...THE GFS HAS BEEN A LITTLE MORE AGGRESSIVE THAN OTHER MODELS WITH THE SOUTHWARD PUSH OF THE AREA OF HIGH PRESSURE INTO THE OHIO VALLEY...AND WOULD SUPPORT AN EVEN DRIER FORECAST FOR THURSDAY AND THE FIRST HALF OF FRIDAY. TEMPERATURES AND DEWPOINTS ARE EXPECTED TO CHANGE VERY LITTLE OVER THE COURSE OF THE WEEK. A VERY SLIGHTLY DRIER AIR MASS WILL BE SETTLING IN ON THURSDAY AND INTO FRIDAY...WHICH MAY ALLOW SOME SLIGHTLY COOLER MIN TEMPS ON FRIDAY MORNING. OTHERWISE...MIN TEMPS WILL LIKELY NOT DROP BELOW THE MID 60S. MAX TEMPS SHOULD REMAIN AROUND 80 DEGREES...BUT CONVECTION AND CLOUDS (OR A LACK THEREOF) COULD HAVE AN IMPACT IN EITHER DIRECTION...ESPECIALLY TODAY (TUESDAY) AND WEDNESDAY. FRIDAY MAY BE THE WARMEST DAY OF THE WEEK...WITH DRY AND SUNNY CONDITIONS TO BEGIN THE DAY...WITH WARM ADVECTION KICKING IN. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... MID/UPPER LEVEL FLOW WILL BECOME MORE AMPLIFIED THROUGH THE WEEKEND AS SHORT WAVE ENERGY MOVES OUT OF THE ROCKIES AND INTO THE CENTRAL PLAINS. THIS WILL EVENTUALLY LEAD TO A FRONTAL BOUNDARY PUSHING DOWN TOWARD AND POSSIBLY THROUGH OUR FA THROUGH EARLY NEXT WEEK. HOWEVER...THERE REMAINS QUITE A BIT OF DIFFERENCE BETWEEN THE ECMWF/GFS/CMC WITH HOW FAST AND HOW FAR SOUTH TO PUSH THE FRONT AND WHETHER OR NOT TO STALL IT OUT ACROSS OUR AREA TOWARD THE END OF THE PERIOD. THIS WILL LEAD TO THE POTENTIAL FOR A FAIRLY WET/MORE ACTIVE PERIOD THROUGH THE END OF THE LONG TERM BUT DUE TO THE TIMING UNCERTAINTIES...WILL JUST KEEP POPS IN THE HIGH CHANCE CATEGORY. FRIDAY WILL BE SEASONABLY WARM WITH HIGHS IN THE MID 80S. MORE SEASONABLE TEMPERATURES WILL THEN BEGIN TO PUSH DOWN FROM THE NORTH OVER THE WEEKEND...BUT THEY WILL ULTIMATELY BE DICTATED BY THE PLACEMENT/TIMING OF THE FRONTAL BOUNDARY. FOR THAT REASON...HAVE GENERALLY GONE WITH A MODEL BLEND FOR TEMPERATURES SATURDAY THROUGH MONDAY. && .AVIATION /15Z TUESDAY THROUGH SATURDAY/... OUR REGION WILL BE UNDERNEATH A MOIST SOUTHWEST FLOW ALOFT. MORNING DAYTIME HEATING WILL RESULT IN CUMULUS DEVELOPMENT WITH WINDS PICKING UP FROM THE SOUTH. BY THE AFTERNOON HOURS...A DISTURBANCE WILL ROTATE NORTHEAST INTO THE WESTERN GREAT LAKES. A TRAILING TAIL/INFLECTION IN THE MID LEVELS WILL TEAM UP WITH A POTENTIAL LOW LEVEL CONVERGENT AXIS TO BRING THE LIKELIHOOD OF SHOWERS AND THUNDERSTORMS. THERE CONTINUES TO BE SOME TIMING AND EVOLUTION ISSUES WITH THE HIGH RESOLUTION MODELS. HAVE PICKED A 3 HOUR TEMPO WINDOW WHEN THE BEST CHANCE FOR THUNDERSTORMS SHOULD BE AT EACH TAF SITE LATE THIS AFTERNOON INTO THIS EVENING. WITH THE MOIST AIRMASS IN PLACE...MVFR CONDITIONS WILL BE LIKELY WITH STORMS WITH LOCAL POCKETS OF IFR CONDITIONS (MOST LIKELY VISIBILITIES) DUE TO HEAVY RAINFALL IN THE STRONGEST CORES. FOR TONIGHT...DISTURBANCE AND ITS TAIL/INFLECTION WILL PUSH OFF TO THE NORTHEAST THROUGH THE REMAINDER OF OUR REGION. WITH THE LOSS OF DAYTIME HEATING...WE SHOULD SEE A GRADUAL DECREASE IN THUNDERSTORM ACTIVITY...WITH JUST A FEW SHOWERS LINGERING IN THE MOIST FLOW LATE TONIGHT. MODELS SUGGEST THAT MVFR/IFR CEILINGS (DUE TO POTENTIAL STRATUS) MAY DEVELOP IN THE 06Z TO 12Z. HAVE ADDED MVFR CEILINGS TO THE TAF SITES FOR NOW. .OUTLOOK...MVFR/IFR CEILINGS POSSIBLE WEDNESDAY MORNING. THUNDERSTORMS POSSIBLE WEDNESDAY AFTERNOON AND EVENING...AND AGAIN SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM... SHORT TERM...HATZOS LONG TERM...JGL AVIATION...HICKMAN

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