Area Forecast Discussion
Issued by NWS

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000
FXUS61 KPBZ 242332
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
732 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/...
WITH 6PM UPDATE...MADE MINIMAL CHANGES TO SKY AND TEMPERATURE
TRENDS INTO THE OVERNIGHT HOURS. 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.

&&

.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 /00Z 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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