Area Forecast Discussion
Issued by NWS Wilmington, OH

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000 FXUS61 KILN 301042 AFDILN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 642 AM EDT SAT AUG 30 2014 .SYNOPSIS... A SERIES OF UPPER LEVEL DISTURBANCES WILL MOVE EAST ACROSS THE REGION THROUGH EARLY NEXT WEEK...RESULTING IN A CONTINUED CHANCE OF THUNDERSTORMS. && .NEAR TERM /THROUGH TONIGHT/... WEAK LOW LEVEL CONVERGENT BOUNDARY HAS LIFTED OFF TO OUR NORTH EARLY THIS MORNING. THIS HAS ALLOWED FOR VERY ISOLATED SHOWER/THUNDERSTORM ACTIVITY TO COME TO AN END ACROSS OUR FA FOR THE TIME BEING. IN A CONTINUED WAA/ISENTROPIC LIFT PATTERN...PCPN CHANCES WILL INCREASE THROUGH THIS AFTERNOON AS WE DESTABILIZE. HOWEVER...PCPN COVERAGE WILL PRIMARILY HINGE ON HOW FAST WE BEGIN TO SEE THE INFLUENCE OF THE COMBINATION OF SOME SHORT WAVE ENERGY MOVING ACROSS THE LOWER GREAT LAKES ALONG WITH SOME ADDITIONAL ENERGY LIFTING UP FROM THE SOUTHWEST. THERE IS SOME MODEL UNCERTAINTY AS TO HOW FAST THIS WILL HAPPEN TODAY BUT MOST OF THE CONVECTIVE ALLOWING MODELS ARE SUGGESTING AT LEAST SOME ISOLATED TO SCATTERED ACTIVITY WORKING INTO OUR WESTERN AREAS LATER THIS AFTERNOON. WILL THEREFORE GO AHEAD AND ALLOW FOR CHANCE POPS TO SPREAD IN FROM THE WEST LATER TODAY. INCREASING CLOUDS FROM THE WEST MAY HELP MODERATE TEMPERATURES SOMEWHAT AND WILL RANGE HIGHS FROM THE MID 80S WEST TO AROUND 90 IN THE EAST. && .SHORT TERM /SUNDAY THROUGH MONDAY/... THE MID/UPPER LEVEL TROUGH MOVING OUT OF THE MID MISSISSIPPI VALLEY WILL WEAKEN AS IT PROGRESSES EAST ACROSS THE UPPER OHIO VALLEY TONIGHT THROUGH SUNDAY. AS IT DOES...THE FLOW ALOFT WILL TRANSITION INTO MORE OF A ZONAL FLOW PATTERN WITH A SERIES OF UPPER LEVEL SHORT WAVES MOVING EAST ACROSS OUR AREA TONIGHT THROUGH SUNDAY. THIS WILL LEAD TO AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS TONIGHT...ESPECIALLY ACROSS SOUTHERN AND SOUTHEASTERN PORTIONS OF OUR FA...WHERE A DEVELOPING 925-850 JET WILL NOSE IN FROM THE SOUTH LATER TONIGHT. FAIRLY HIGH PCPN CHANCES WILL CONTINUE INTO SUNDAY AS MOIST SOUTHWESTERLY LOW LEVEL FLOW PERSISTS. IT LOOKS LIKE WE MAY GET INTO A BIT OF A LULL SUNDAY NIGHT INTO MONDAY MORNING AS BETTER SHORT WAVE ENERGY PUSHES OFF TO THE EAST. AS WE DESTABILIZE THROUGH THE DAY ON MONDAY...SOME ISOLATED THUNDERSTORM ACTIVITY WILL AGAIN BE POSSIBLE...ESPECIALLY DURING THE AFTERNOON HOURS. CLOUDS AND PCPN SHOULD HELP KEEP HIGHS GENERALLY DOWN IN THE LOWER 80S FOR SUNDAY...WITH TEMPERATURES THEN WARMING BACK UP INTO THE MID 80S FOR MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... HAVE USED A BLEND OF THE 00Z ECMWF AND THE 12Z ECMWF FOR THE LONG TERM FORECAST. EACH MODEL RUN WAS SIMILAR TO EACH OTHER WITH TIMING AND PLACEMENT OF UPCOMING SYNOPTIC SYSTEMS. ALSO..THE GFS SEEM TOO FAST IN PUSHING A WARM FRONT BACK NORTHWARD MID WEEK BASED ON MID TO UPPER LEVEL FLOW. FOR MONDAY NIGHT INTO TUESDAY NIGHT...A COLD FRONT WILL SLOWLY SAG SOUTHEAST INTO THE REGION...EVENTUALLY STALLING OUT SOMEWHERE OVER THE CNTRL OR SRN CWFA BY WEDNESDAY MORNING. BEST UPR LVL DYNAMICS PASS BY TO THE NORTH ON TUESDAY AFTERNOON AND EVENING. HOWEVER...ENOUGH HEATING AND FRONTAL CONVERGENCE CALL FOR AT LEAST 40 TO 50 POPS. ON WEDNESDAY...FRONTAL BOUNDARY AS MENTIONED IS EXPECTED TO STALL OVER THE AREA WHILE MID LEVEL FLOW BEGINS TO BUCKLE A LITTLE. WILL CONTINUE WITH A LOW CHANCE FOR SHOWERS/STORMS...MAINLY CNTRL AND SRN SECTIONS THROUGH WEDNESDAY AFTN/EARLY EVENING. LOOKS LIKE MID LEVEL RIDGE TO OUR SOUTH WILL TRY TO BUILD NORTHWARD THURSDAY INTO FRIDAY AHEAD OUT AHEAD OF THE NEXT S/WV AND COLD FRONT TO MOVE INTO THE REGION BY THE WEEKEND. HAVE KEPT THURSDAY DRY IN THE MOIST RETURN FLOW ALTHOUGH THERE IS A VERY SMALL CHANCE FOR A POP UP SHOWER OR STORM. HAVE GONE WITH 20 AND 30 POPS ON FRIDAY AHEAD OF THE APPROACHING COLD FRONT. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR OR ABOVE SEASONAL NORMALS FOR EARLY SEPTEMBER. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... LATEST RADAR LOOPS EARLY THIS MORNING SHOWING NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS OVER WESTERN INDIANA MOVING TO THE NORTH NORTHEAST. LATEST NUMERICAL GUIDANCE SHOWS THIS AREA OF PCPN WEAKENING OVER THE NEXT COUPLE OF HOURS...THUS THIS POSSIBILITY OF PCPN IS NOT INCLUDED IN THE 12Z FORECAST AT THIS TIME. OUTSIDE OF THIS CONCERN THE UPDATED 12Z FORECASTS CONTINUE TO CUTBACK AND DELAY THE CONVECTION DURING THE DAY. LOW LEVEL CONVERGENCE WILL CONTINUE TO INCREASE DURING THE DAY AND THIS ALONG WITH THE DAYTIME HEATING WILL LEAD TO THE DEVELOPMENT OF THUNDERSTORMS LATE THIS AFTERNOON ACROSS THE FORECAST AREA. VFR CONDS ARE EXPECTED TODAY FOR MOST OF THE AREA WITH THE EXCEPTION OF SOME EARLY MORNING OHIO RIVER VALLEY FOG. SURFACE WINDS TODAY SHOULD BE SW 5 TO 15KT WITH GUSTS TO 20KT. EARLY TONIGHT THE COMBINATION OF INCREASE LOW LEVEL CONVERGENCE WITH A MID TO UPPER LEVEL TROUGH WILL SIGNIFICANTLY INCREASE THE CHANCES OF PCPN. THE PCPN SHOULD COME IN THE FORM OF NUMEROUS SHOWERS AND WIDELY SCATTERED EMBEDDED THUNDERSTORMS LASTING BEYOND THE TAF FORECAST PERIOD. THE CURRENT THINKING IS THAT THE BULK OF THE PCPN WILL BE ALONG AND TO THE SOUTH OF I-71. AS THE PCPN PERSISTS THROUGH THE NIGHTTIME HOURS CIGS AND VSBYS WILL GRADUALLY LOWER TO MVFR. IF THE PCPN BECOMES MORE CONTINUOUS...RAIN INSTEAD OF SHOWERS THE SE TAFS...KCVG, KLUK, AND KILN COULD SEE IFR CIGS AND VSBYS AFTER 09Z. EXPECT UPDATED FORECASTS TO HOME IN ON THIS ISSUE. SURFACE WINDS TONIGHT WILL BE SW AT 10KT OR LESS. OUTLOOK...SCATTERED THUNDERSTORMS POSSIBLE THROUGH WEDNESDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...HICKMAN AVIATION...HAYDU

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