Area Forecast Discussion
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000 FXUS61 KPBZ 292158 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 558 PM EDT MON JUN 29 2015 .SYNOPSIS... A SERIES OF DISTURBANCES WILL KEEP PERIODIC RAIN CHANCES THROUGH MUCH OF THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... SHOWERS ARE EXPECTED TO CONTINUE TO ADVANCE ACROSS THE REGION THIS EVENING AHEAD OF AN APPROACHING WARM FRONT. A FEW THUNDERSTORMS ARE POSSIBLE SOUTH OF PIT THOUGH MOST OF THE AVAILABLE INSTABILITY IS PROGGED TO REMAIN SOUTH OF OUR AREA. ADDITIONAL SHOWERS WILL REMAIN POSSIBLE AS THE WARM FRONT CROSSES OVERNIGHT...THOUGH WITH LACK OF LOW LEVEL JET AND SUFFICIENT INSTABILITY LEFT THUNDER OUT OF THE FORECAST OVERNIGHT. A RELATIVE BREAK IN THE PRECIP IS EXPECTED TUESDAY MORNING ANOTHER SHORTWAVE AND ASSOCIATED COLD FRONT APPROACH LATER IN THE DAY WITH INCREASING SHOWER/STORM CHANCES. MODEL PROGGED SHEAR AND INSTABILITY ARE MARGINAL...SO THE POTENTIAL FOR STRONG STORMS IS IN QUESTION. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... BROAD UPPER TROUGH WILL DOMINATE THE EASTERN CONUS THROUGH MID- WEEK...WITH SEVERAL SHORTWAVE TROUGHS EXPECTED TO MOVE THROUGH THE FLOW. THUNDERSTORMS ARE EXPECTED AT THE START OF THE TUESDAY NIGHT PERIOD...BUT THESE SHOULD WANE QUICKLY AS THEIR SUPPORTING UPPER WAVE DEPARTS AND DRIVES THE ASSOCIATED COLD FRONT SOUTHWARD. THIS COLD FRONT WILL BECOME STALLED ACROSS THE FORECAST AREA ON WEDNESDAY...AND LIKELY WILL BE THE FOCUS FOR ADDITIONAL SHOWERS AND STORMS ON WEDNESDAY AFTERNOON AS MODEST INSTABILITY PERSISTS IN THE WARM SECTOR...AND ANOTHER SHORTWAVE TROUGH IMPINGES ON THE REGION. TEMPERATURES ON WEDNESDAY WILL NOT DEPART MUCH FROM NORMAL VALUES. AMID INCREASING CUMULUS COVER...HIGHS ARE EXPECTED IN THE UPPER 70S-LOWER 80S...WITH MINIMA IN THE LOWER 60S. && .LONG TERM /THURSDAY THROUGH MONDAY/... ALTHOUGH THE LONGWAVE TROUGH WILL FLATTEN SOMEWHAT IN THE MEDIUM RANGE...A PROGRESSIVE PATTERN WILL PERSIST...WITH SEVERAL SHORTWAVE TROUGHS EXPECTED TO IMPACT THE REGION LATE-WEEK THROUGH THE WEEKEND. A STALLED FRONTAL BOUNDARY WILL BE DIVERTED QUITE LITTLE DURING THIS TIME...AND WILL PROVIDE FOCUS FOR DAILY ROUNDS OF SHOWERS AND STORMS. MODELS DO NOT AGREE ON DETAILS AT THIS RANGE...BUT THE GENERAL PICTURE IS THAT A SHORTWAVE TROUGH FROM THE SOUTHERN PLAINS MOVES ALONG THIS STALLED BOUNDARY LATE IN THE WEEK. THE PRECISE POSITION OF THE STALLED FRONT WILL DICTATE THE COVERAGE OF ANY ASSOCIATED PRECIPITATION IN THE PITTSBURGH FORECAST AREA...BUT CONSENSUS SUGGESTS THAT THE SOUTHERNMOST PORTION OF THE AREA HAS THE GREATEST LIKELIHOOD OF MEASURABLE RAIN. THUS...POPS WERE ADJUSTED IN THE LATTER HALF OF THE WEEK TO DEPICT A BIT MORE OF A GRADIENT. THERE IS NO INDICATION THAT TEMPERATURES WILL DEVIATE FROM CLIMATOLOGICAL NORMALS BY ANY SIGNIFICANT DEGREE. MAXIMA IN THE UPPER 70S-LOWER 80S AND MINIMA IN THE LOWER 60S SHOULD BE COMMON AT LEAST THROUGH THE WEEKEND. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... VFR CONDITIONS PERSIST EARLY THIS EVENING...DESPITE LIGHT RAIN SHOWERS. DRY LOW-LEVELS WILL KEEP RESTRICTIONS LIMITED UNTIL FURTHER SATURATION OCCURS LATER THIS EVENING. WARM FRONT WILL PASS LIGHT RAIN MAINLY TO THE NORTH...BUT REMNANT SHOWER AND THUNDERSTORM ACTIVITY ALONG A MID-LEVEL WAVE WILL MOVE IN LATER TONIGHT AND OVERSPREAD THE AREA. THE BEST CHANCES FOR ANY THUNDERSTORMS TO PERSIST ARE ALONG THE SOUTHERN TERMINALS...BUT CONFIDENCE IS NOT HIGH ENOUGH FOR INCLUSION AT THIS TIME. EXPECTING MAINLY MVFR CIGS FOR MOST LOCATIONS PRE-DAWN...WITH SOME IFR ALONG THE NORTH WITH THE DEEPER MOISTURE. CONDITIONS WILL IMPROVE QUICKLY AFTER SUNRISE TUESDAY...BUT MORE RESTRICTIONS ARE POSSIBLE IN AFTERNOON SHOWERS/THUNDERSTORMS. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... PERIODIC RESTRICTIONS ARE POSSIBLE THROUGH THE WEEK WITH A SERIES OF CROSSING DISTURBANCES. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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