Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 200138 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 938 PM EDT TUE AUG 19 2014 .SYNOPSIS... A FRONTAL BOUNDARY WILL REMAIN WELL TO OUR SOUTH AND WEST FOR THE NEXT SEVERAL DAYS. SURFACE LOW PRESSURE AND AN ASSOCIATED LOW ALOFT WILL MOVE SOUTHEASTWARD FROM THE GREAT LAKES ON THURSDAY INTO FRIDAY BRINGING A GOOD CHANCE FOR SHOWERS AND A FEW THUNDERSTORMS. A RIDGE OF HIGH PRESSURE WILL THEN BECOME ESTABLISHED OVER THE REGION AND BRING MAINLY FAIR WEATHER FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LOW PRESSURE WAS LOCATED WELL OFF THE VIRGINIA COAST THIS EVENING. IT WILL CONTINUE TO DRIFT OUT TO SEA. MEANWHILE, A SURFACE RIDGE EXTENDED ALONG THE APPALACHIANS. WE ARE ANTICIPATING A PARTLY TO MOSTLY CLOUDY SKY OVERNIGHT, ALONG WITH A LIGHT WIND. THE WIND DIRECTION WILL FAVOR EAST TO SOUTHEAST. THE CLOUD COVER SHOULD PREVENT TEMPERATURES FROM FALLING BELOW THE 60S AT MOST LOCATIONS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... THE EASTERLY, ONSHORE FLOW IS FORECAST TO CONTINUE ACROSS THE REGION THROUGH WEDNESDAY AS WEAK LOW PRESSURE WILL SLOWLY EDGE FARTHER EAST AND AWAY FROM THE COAST, WITH WEAK HIGH PRESSURE REMAINING SITUATED ACROSS PORTIONS OF NEW ENGLAND. THE NEXT FEATURE OF INTEREST WILL BE A MID-LEVEL SHORTWAVE PROGRESSING EASTWARD FROM THE LOWER GREAT LAKES/UPPER OHIO VALLEY REGION ACROSS CENTRAL PA THROUGH THE DAYTIME WEDNESDAY. THERE IS FAIRLY GOOD MODEL AGREEMENT BETWEEN THE GFS, NAM, AND ECMWF WITH REGARDS TO THIS SHORTWAVE REMAINING OFF TO OUR WEST THROUGH THE DAYTIME AND THUS HOLDING MOST PRECIP CHANCES FOR OUR WESTERN ZONES UNTIL LATER WEDNESDAY EVENING/NIGHT, AND WE HAVE ONLY SOME LOW POPS FOR ISOLATED ACTIVITY INTO THE EVENING. FOR HIGH TEMPERATURES WEDNESDAY, WE MAINLY TOOK A MET/MAV BLEND, BUT THEN EDGED MAX TEMPERATURES DOWN A DEGREE OR TWO ALONG THE COAST WITH THE PERSISTENT ONSHORE FLOW. MAXIMUM TEMPERATURES SHOULD MOSTLY RANGE FROM THE UPPER 70S ALONG THE COAST AND IN THE SOUTHERN POCONOS TO THE LOWER 80S ELSEWHERE. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... AN OVERALL RATHER BENIGN AUGUST WEATHER PATTERN WILL CONTINUE FOR THE MID-ATLANTIC REGION FOR THE NEXT SEVERAL DAYS. AN UPPER LOW NOW OVER THE WESTERN GRTLKS IS FORECAST TO WEAKEN AS IT MOVES SOUTHEAST ACROSS THE LOWER GRTLKS AND NY STATE DURING THURSDAY AND FRIDAY...THEN REDEVELOPING SOMEWHAT EAST OF NEW ENGLAND OVER THE WEEKEND. MEANWHILE AN UPPER LEVEL RIDGE IS FORECAST TO BUILD OVER THE MS VALLEY...RESULTING IN CONFLUENT/SUBSIDENT FLOW OVER THE REGION FOR MOST OF THE WEEKEND INTO EARLY NEXT WEEK. AS THE UPPER LOW/TROF MOVE BY ON THU/FRI...THERE IS SOME FORCING FOR UVV ALONG WITH INCREASING PW AND MODEST INSTBY. THUS A PERIOD OF SHOWERS/TSTMS IS EXPECTED WITH HIGHEST POPS LATE THU AND THU NIGHT. THE CHC POPS CONTINUE INTO FRI ALTHOUGH INSTBY SEEMS MARGINAL AT THAT TIME. FOR THE WEEKEND A SURFACE HIGH PRESSURE RIDGE IS EXPECTED TO BUILD OVER NEW ENGLAND...RESULTING IN A SOMEWHAT COOLER AND DRIER FLOW INTO THE MID-ATLANTIC REGION. MAX/MIN TEMPS THROUGH THE PERIOD ARE FORECAST TO REMAIN WITHIN A FEW DEGREES OF NORMAL. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD WITH ONE EXCEPTION. SOME LIGHT FOG MAY IMPACT KRDG AND KMIV AROUND DAYBREAK. THE CLOUD COVER WILL VARY FROM BROKEN TO SCATTERED WITH ANY CEILINGS REMAINING AT OR ABOVE 4000 FEET. THE WIND IS FORECAST TO REMAIN LESS THAN 10 KNOTS. THE DIRECTION SHOULD FAVOR THE SOUTHEAST TO EAST OVERNIGHT THEN IT IS EXPECTED TO VEER TOWARD THE SOUTHEAST AND SOUTH ON WEDNESDAY. OUTLOOK... WEDNESDAY NIGHT THROUGH FRIDAY...CHANCE FOR SHRA/TSRA AS A SERIES OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY FLIGHT MVFR RESTRICTIONS POSSIBLE. WINDS MAINLY EAST TO SOUTHEAST. FRIDAY NIGHT THROUGH SUNDAY...PREDOMINATELY VFR CONDITIONS WITH NORTHEAST WINDS. && .MARINE... AN OVERALL EASTERLY TO EAST-SOUTHEAST FLOW IS EXPECTED TO CONTINUE ACROSS OUR COASTAL WATERS AND DELAWARE BAY TONIGHT THROUGH WEDNESDAY. WIND SPEEDS WILL MOSTLY BE IN THE 5 TO 15 KNOT RANGE FOR OUR WATERS THROUGH THIS PERIOD, STRONGEST FOR OUR SOUTHERN COASTAL WATERS. SEAS WILL MOSTLY BE IN THE 2 TO 4 FOOT RANGE FOR THE COASTAL WATERS TONIGHT THROUGH WEDNESDAY, WITH 1 TO 3 FOOT SEAS FOR DELAWARE BAY. OUTLOOK... THURSDAY THROUGH FRIDAY...NO SCA FLAGS EXPECTED WITH WINDS/SEAS BELOW THRESHOLDS. HOWEVER... LOCALLY ROUGH CONDS ARE POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS. SATURDAY AND SUNDAY...A PERSISTENT NORTHEAST FLOW WILL LIKELY RESULT IN BUILDING SEAS AND GUSTY WINDS. MARGINAL SCA CONDS ARE POSSIBLE ATTM. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...AMC NEAR TERM...IOVINO SHORT TERM...KLINE LONG TERM...AMC AVIATION...AMC/IOVINO MARINE...AMC/KLINE

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