Area Forecast Discussion
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000 FXUS61 KPBZ 202332 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 732 PM EDT SUN JUL 20 2014 .SYNOPSIS... GRADUAL WARMING AND MORE HUMID CONDITIONS CAN BE EXPECTED UNTIL PASSAGE OF A COLD FRONT MIDWEEK. && .NEAR TERM /THROUGH MONDAY/... ISOLATED SHOWERS CONTINUE TO FIRE IN THE VICINITY OF WHAT IS LEFT OF A INVERTED SURFACE TROUGH. WITH THE ATMOSPHERE EXPERIENCING MODEST DESTABILIZATION...SHOWERS ARE FIRING IN AN AREA OF HIGHER MOISTURE CONVERGENCE. A WEAK SHORTWAVE TROUGH WILL SPLIT AND CROSS THE REGION OVERNIGHT. ANY ASCENT FROM THIS WAVE WILL BE MINOR. EVIDENCE OF THIS UPPER LEVEL WAVE IS PRESENT ON THE LATEST SAT PICS THAT ARE SHOWING A LINE OF CU EXITING SOUTHERN LAKE ERIE. ISO SHOWERS ARE ALSO FIRING OVER NORTHEASTERN OHIO AHEAD OF THE WAVE. WILL KEEP IN THE MENTION OF ISO SHOWERS THROUGH THE EVENING HOURS... COVERING THE WEAK LIFT FROM THE SHORTWAVE. LOSS OF SUNLIGHT WILL HELP TO QUIET AIR PARCELS...SO WILL REMOVE POPS LATER TONIGHT. LATEST MESOANALYSIS SUGGEST VERY MODEST INSTABILITY AND PRACTICALLY NO SHEAR...AS WAS PROGGED ON THE DETERMINISTIC RUNS THIS MORNING. WHILE LITTLE IN THE WAY OF SHOWER DEVELOPMENT HAS OCCURRED THUS FAR...STILL THINK THAT A A FEW SHOWERS AND POSSIBLY A THUNDERSTORM WILL BE POSSIBLE THROUGH LATE AFTERNOON/EARLY EVENING AS A VERY WEAK SHORTWAVE CROSSES THROUGH THE UPPER TROUGH. MAINTAINED THE HIGHEST POPS...WHICH IS STILL IN THE 30-40`S ACROSS THE RIDGES...WHERE OROGRAPHIC ENHANCEMENT MAY SUPPORT A BIT MORE COVERAGE. WITH LOW LEVEL MOISTURE REMAINING IN PLACE...DO NOT THINK THAT SKIES WILL COMPLETELY CLEAR OUT OVERNIGHT. FORECAST LOWS WILL REFLECT THIS...WITH TEMPS STAYING IN THE 60`S. ON MONDAY...LITTLE CHANGE WAS NEEDED IN THE FORECAST AS AN UPPER RIDGE OVER THE WEST EDGES TOWARDS THE OHIO VALLEY. IF A SHOWER OR THUNDERSTORM DOES DEVELOP...IT WOULD MOST LIKELY BE ALONG THE HIGHER ELEVATIONS WITH OROGRAPHIC ENHANCEMENT SINCE THERE WILL BE LITTLE ELSE TO SUPPORT LIFT. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... MAIN HIGHLIGHT FOR TUESDAY WILL BE THE ABOVE AVERAGE TEMPERATURES AND HUMIDITY AS THE UPPER RIDGE BUILDS FARTHER EAST. ON WEDNESDAY...AN UPPER TROUGH WILL BEGIN TO DIG SOUTHWARD OVER THE GREAT LAKES...BRINGING THE NEXT CHANCE FOR WIDESPREAD PRECIPITATION WITH A COLD FRONT BY LATE IN THE PERIOD. WITH THE MODELS IN RELATIVELY GOOD AGREEMENT ON TIMING...HAVE BUMPED UP POPS BY LATE IN THE DAY. WEDNESDAY SHOULD ONCE AGAIN BE A WARM AND HUMID DAY DESPITE INCREASING CLOUD COVER AHEAD OF THE FRONT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MINIMAL CHANGE WAS NEEDED TO THE EXTENDED AS MODELS SHOW DECENT AGREEMENT AND CONTINUITY REGARDING A MIDWEEK COLD FRONT SET TO PASS THROUGH THE FORECAST AREA. ADJUSTMENTS WERE MADE TO RAISE POPS WEDNESDAY EVENING AS THIS LOOKS TO BE THE APPROXIMATE TIMING OF FROPA ATTM. ADDITIONALLY...ANALYSIS OF LATEST 10 GFS RUNS SHOWS MINIMAL CHANGE IN POSITION AND HEIGHTS...INCREASING CONFIDENCE IN TIMING AS WELL. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR FOR THE EVENING HOURS WITH SOME SC/AC TO DEAL WITH. OVERNIGHT...SKIES SHOULD REMAIN CLEAR ENOUGH TO ALLOW FOG FORMATION...AN MVFR MIST IN GENERAL BUT IFR TO LIFR POSSIBILITIES IN THE VALLEYS. ANY FOG SHOULD DISSIPATE BY 13Z...LEAVING ANOTHER ROUND OF AFTERNOON CU IN ITS WAKE. OUTLOOK.../MONDAY THROUGH THURSDAY/...A COLD FRONT WILL RESULT IN WIDESPREAD RESTRICTIONS AS IT PASSES THROUGH DURING THE MIDDLE OF THE WEEK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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