Area Forecast Discussion
Issued by NWS

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000 FXUS61 KPBZ 250115 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 915 PM EDT SUN AUG 24 2014 .SYNOPSIS... UPPER LEVEL HIGH PRESSURE PROVIDES SUMMER LIKE WEATHER THE FIRST PART OF THE WORK WEEK. TEMPERATURES WILL BE ABOVE NORMAL WHILE HUMID CONDITIONS ARE FORECAST. A COLD FRONT BRINGS THE CHANCE FOR SHOWERS AND THUNDERSTORMS WEDNESDAY. READINGS FALL BACK TO SEASONAL NUMBERS BY THE END OF THE WORK WEEK. && .NEAR TERM /THROUGH MONDAY/...
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WITH 915PM UPDATE...MADE ADDITIONAL SMALL CHANGES TO CLOUD FORECAST. ALTHOUGH SCATTERED CLOUDS REMAIN THIS EVENING...REST OF CLOUDS SHOULD DISSIPATE OVERNIGHT. ALSO TWEAKED HOURLY TEMPERATURE TRENDS. PREVIOUS DISCUSSION FOLLOWS. HIGH PRESSURE SLIDES SOUTHEAST INTO NEW ENGLAND TONIGHT...THIS KEEPS SE WINDS IN PLACE. MOST LOCATIONS WILL LOSE THE CUMULUS FIELD AROUND DUSK...SAVE FOR GARRETT WHERE LOW CLOUDS SHOULD PERSIST INTO THE EVENING HOURS AND COULD LINGER THROUGH THE OVERNIGHT. FAR WESTERN AREAS /ZZV-PHD VCNTY/ GIVEN PRESSURE GRADIENT WILL EXPERIENCE LIGHTER WINDS AND THUS COULD SEE FOG DEVELOPMENT ESPECIALLY IN THE DEEPER VALLEYS. ANY FOG WILL BURN OFF BY MID MORNING OWING TO A MOSTLY SUNNY DAY. AFTERNOON TRIGGER TEMPERATURES RESIDE IN THE LOWER 80S AND WITH H8 TEMPS A DEGREE HIGHER...EXPECT ANOTHER AFTERNOON WITH FAIR WEATHER CLOUDS. MAX AND MIN TEMPERATURES WERE A BLEND OF THE SREF BIAS CORRECTED AND EXISTING FORECAST.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... MID LEVEL ANTICYCLONE BUILDS INTO THE OHIO VALLEY THE EARLY PART OF THE WORK WEEK PROVIDING CONSECUTIVE DAYS IN THE MIDS 80S...WHICH HAS RARELY BEEN OBSERVED THIS SUMMER. LAST TIME WE ATTAINED A STRING OF HIGHS SIMILAR TO WHAT IS FORECAST WAS IN LATE JULY. PATCHY FOG IS POSSIBLE MONDAY NIGHT AS NIGHTS CONTINUE TO BECOME LONGER...FOR NOW CONFIDENCE WAS TOO LOW FOR INCLUSION INTO THE DIGITAL FORECAST. TUESDAY...HIGH PRESSURE ALOFT WEAKENS ALLOWING MID LEVEL FLOW TO BECOME ZONAL. SKY COVER SHOULD BE THE LEAST TUESDAY BASED ON BUFR SOUNDINGS WITH ATMOSPHERIC COLUMN ILLUSTRATING LARGE DEW POINT DEPRESSIONS. CU FIELD SHOULD BE FEW-SCT GIVEN RH PROGS AND TEMPERATURES IT WILL TAKE BEFORE CCL IS REACHED. BY NIGHT TIME...SHORTWAVE TROUGH COULD BE RIDING THROUGH THE ZONAL FLOW AND GENERATE SHOWERS/THUNDERSTORMS OVER NWRN PA. SCHC POPS WERE MAINTAINED FOR THIS GIVEN CONTINUITY AMONGST 12Z NCEP SUITE. FALLING HEIGHTS RESULTING FROM LOW PRESSURE OVER SRN CANADA ALLOWS A BAROCLINIC ZONE TO DROP SOUTHEAST THROUGH THE AREA. AT THIS JUNCTURE IT APPEARS A LEFTOVER THUNDERSTORM COMPLEX WILL SKIRT THROUGH THE CWA DURING THE SECOND HALF OF WEDNESDAY. INSTABILITY PARAMETERS ARE NOT IMPRESSIVE NEITHER ARE UPPER LEVEL DYNAMICS...SO ANY STORM SHOULD STAY BELOW SEVERE LIMITS. BRIEF DOWNPOURS ARE POSSIBLE GIVEN PWATS BETWEEN 1.5 AND 1.75 INCHES. TIMING AND PLACEMENT DIFFERENCES WARRANT CHANCE POPS FOR NOW. MUCH LIKE THE NEAR TERM...A BLEND OF THE ONGOING FORECAST AND BIAS CORRECTED SREF GRIDS WERE USED FOR TEMPS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DISCREPANCIES EXIST IN THE LARGE SCALE FEATURES TOWARDS THE END OF THE WEEK. 12Z ECMWF DROPS A WEAK COLD FRONT ALONG OUR NORTH ALL THE WAY THROUGH OUR CWA BY THURS AFTERNOON. THIS FEATURE...DOUBLED DOWN ON BY THE 00Z ECMWF/CMC...WOULD MEAN SFC HIGH PRESSURE FILLING BACK IN ACROSS OUR NORTH BY THE EARLY WEEKEND. THIS SOLN IS AT ODDS WITH THE GFS THAT HAS BEEN CONSISTENT IN KEEPING THE WEAK FRONT NORTH OF THE AREA THROUGH THE BALANCE OF THE WEEK. WITH FLOW MOSTLY PARALLEL TO THE FRONT THROUGH MID-WEEK...HAVE A TOUGH TIME BELIEVING THE FRONT CLEARS THE AREA COMPLETELY. HAVE SETTLED ON A BLEND FOR THIS UPDATE FAVORING THE GFS SLIGHTLY...THINKING THE FRONT WILL DRAPE ACROSS OUR AREA KEEPING US IN DAILY SHOWER CHANCES WITH NEAR NORMAL TEMPERATURES. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... SCT CU DYING OFF WITH ONLY SOME CIRRUS OVERNIGHT INTO MONDAY. WIDESPREAD FOG DEVELOPMENT NOT EXPECTED OVERNIGHT WITH LARGER DEW POINT DEPRESSIONS AND LIGHT SE WINDS. ONLY A PERIOD OF MVFR EXPECTED AT KZZV. VFR AND LIGHT SOUTHEAST WINDS MONDAY. OUTLOOK.../MONDAY AFTERNOON THROUGH FRIDAY/... SCATTERED SHOWERS AND THUNDERSTORMS COULD CREATE VSBY/CIG RESTRICTIONS WED...HOWEVER AS OF NOW THEY ARE NOT FORECAST TO BE WIDESPREAD. && .EQUIPMENT... WHEELING ASOS IS OUT OF SERVICE WHICH HAS AN EFFECT ON THE DAILY CLIMATE. NO ETA ON WHEN IT WILL RETURN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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