Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 191404 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1004 AM EDT TUE AUG 19 2014 .SYNOPSIS... QUASI-STATIONARY FRONTAL BOUNDARY TO THE SOUTH OF THE REGION WILL SLOWLY SLIP FARTHER SOUTH THIS WEEK AS SEVERAL WAVES OF LOW PRESSURE MOVE EASTWARD ALONG IT. NEW ENGLAND HIGH PRESSURE NOSES IN OVER THE WEEKEND AND REMAINS NEARLY STATIONARY THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THIS MORNING`S SURFACE ANALYSIS SHOWED WEAK LOW PRESSURE JUST OFF OF THE VIRGINIA CAPES. AS MENTIONED BY THE PREVIOUS SHIFT, THE TRACK OF THIS LOW HAS BEEN A TAD FARTHER SOUTH AND FASTER THAN PREVIOUS MODEL GUIDANCE HAD PROGGED. THUS, THE BULK OF THE PRECIP WITH THE LOW HAS STAYED SOUTH OF DE AND EASTERN MD, FOR THE MOST PART. HOWEVER, AT THIS TIME, WE CANNOT COMPLETELY RULE OUT AN ISOLATED SHOWER OR TWO AS THERE HAVE BEEN EARLIER TODAY, AND WE HAVE KEPT SLIGHT CHANCE POPS IN THROUGH THE MORNING OVER SOUTHERN PORTIONS OF OUR DELMARVA AREA. WE ALSO ADJUSTED SKY COVER SOME ACROSS THE SOUTHERN DELMARVA, FAR SOUTHERN NJ, AND ALONG THE MONMOUTH TO OCEAN COUNTY COASTS WHERE SOME LOWER CLOUDS REMAIN, BUT THE OVERALL TREND WILL BE FOR THE CLOUDS TO ERODE SOMEWHAT THROUGH THE DAY. ONLY SOME MINOR ADJUSTMENTS TO HOURLY TEMPS AND DEWPOINTS WERE NEEDED THROUGH MORNING AND INTO THE AFTERNOON, AND TODAY`S MAXIMUM TEMPERATURES LOOK ON TRACK AFTER CHECKING 12Z REGIONAL SOUNDING DATA. OTHERWISE, SKY COVER WAS RANGING FROM OVERCAST IN FAR SOUTHERN NJ AND THE DELMARVA TO FEW IN NORTHERN NJ BEFORE DRIER AIR MOVES IN BEHIND THE SYSTEM AND CLOUDS ERODE. THE ONE EXCEPTION TO THE CLOUD COVER WILL BE OUT TOWARD MQS-RDG-MPO. THESE LOCATIONS ARE POSITIONED NEAR OR JUST WEST OF H8 RIDGE AXIS, WHERE BACKING WINDS OUT OF THE SOUTH WILL RESULT IN WEAK ISENTROPIC LIFT AND CLOUDS. AN ISO SHOWER MAY DEVELOP ACROSS THE HIGHER TERRAIN OF PA LATE IN THE AFTERNOON, BUT MOST OF THIS ACTIVITY SHOULD BE FOCUSED DEEPER WITHIN LLVL THETA-E RIDGE, WHICH WILL BE SITUATED WEST OF THE CWA. USED A BLEND OF MAV/MET GUIDANCE FOR MAX TEMPS TODAY BUT WITH ONSHORE FLOW DEVELOPING, UNDERCUT TEMPS A COUPLE OF DEGREES NEAR THE COAST. TEMPS TODAY WILL BE SLIGHTLY BELOW NORMAL, WHICH FITS THE PATTERN ACROSS THE REGION FOR MUCH OF THE MONTH. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... WEAK HIGH PRESSURE OVER NEW ENGLAND WILL START TO NOSE DOWN TOWARD THE NORTHERN MID-ATLANTIC REGION TONIGHT AS LOW PRESSURE MOVES FARTHER OFF THE NC COAST. MOST OF THE FORECAST AREA SHOULD BE ABLE TO CLEAR OUT EXCEPT IN THE FAR WEST. WILL ALSO NEED TO WATCH FOR THE POTENTIAL FOR THE DEVELOPMENT OF LOW CLOUDS/FOG LATE TONIGHT IN COASTAL NJ/DE WITH A PERSISTENT ONSHORE FLOW. MIN TEMPS RANGE FROM THE UPPER 50S IN THE POCONOS TO MID 60S NEAR THE COAST AND IN THE URBAN I-95 CORRIDOR. && .LONG TERM /WEDNESDAY THROUGH TUESDAY/... HEMISPHERIC PATTERN SHOWS RIDGING OFF THE EAST COAST WITH A CLOSED LOW FEATURE OVER THE CANADIAN MARITIMES. WEAK MID-LEVEL RIDGING OVER THE GREAT LAKES WITH A MEANDERING CUT-OFF LOW OVER THE UPPER MID-WEST SLOWLY MOVES EASTWARD WITH TIME AND BECOMES ABSORBED BY THE OPENING OF THE CLOSED LOW OVER THE CANADIAN MARITIMES BY THE WEEKEND. RIDGING MOVES OVERHEAD BY LATE THIS WEEKEND INTO NEXT WEEK. WEDNESDAY...THE 00Z GUIDANCE HAS COME IN A BIT FASTER THAN THE 12Z WITH THE SHORTWAVE ENERGY MOVING ACROSS THE REGION AND THE ASSOCIATED SURFACE BOUNDARY. THAT BEING SAID, THE GUIDANCE STILL KEEPS THE BETTER CHANCES FOR SHOWERS UNTIL THE OVERNIGHT TIMEFRAME AND MOSTLY ACROSS OUR WESTERN ZONES...EASTERLY UPSLOPE FLOW WILL HELP INCREASE CHANCES LATE. THURSDAY - FRIDAY...INCREASING CHANCES FOR SCATTERED SHOWERS AS THE SHORTWAVE MOVES DIRECTLY OVERHEAD ON THURSDAY...LOOKS LIKE THE WETTEST DAY OF THE LONGTERM. MODEST SURFACE BASED CAPE OF 1000J/KG, SOUTHERLY FLOW OUT AHEAD OF THE APPROACHING LOW, COMBINED WITH COLD POOL ALOFT AND STEEPER MID-LEVEL LAPSE RATES, SHOULD BE ENOUGH FOR SCATTERED CONVECTION TO OCCUR...PRIMARILY DIURNALLY DRIVEN. SLOWER MOVEMENT OF THE OPENING MID-LEVEL LOW COULD KEEP SHOWERS AROUND, MOSTLY ACROSS THE SOUTHERN HALF, THROUGH THE FIRST PART OF FRIDAY BEFORE CLEARING OUT. SATURDAY - SUNDAY...NEW ENGLAND HIGH PRESSURE BETTER ESTABLISHES ITSELF PUSHING A RIDGE AXIS DOWN THROUGH OUR REGION. PERSISTENT ONSHORE FLOW SHOULD BE ENOUGH TO KEEP A MAJORITY OF THE REGION STABLE ENOUGH TO OMIT THUNDER FROM THE FORECAST OVER THE WEEKEND. MID-LEVEL LOW/TROUGH WILL BE TO THE SOUTHEAST OF THE REGION WITH MID-LEVEL RIDGING TRYING TO WORK IN FROM THE SOUTHWEST. SURFACE CONVERGENCE LOOKS TO STAY JUST TO THE WEST OF THE REGION AS MORE SHORTWAVE ENERGY DIVES SOUTHEAST WITHIN THE CYCLONIC FLOW ALOFT...RING OF FIRE ACTION IS CLOSE BY. WE KEEP THE FORECAST MOSTLY DRY AT THIS TIME, BUT CONFIDENCE IS LOWER TO OUR WEST AND SOUTH, CLOSER TO THE SURFACE BOUNDARY. MONDAY - TUESDAY...BETTER CHANCE THAT WE WILL BE DRY FOR THE END OF THE LONGTERM AS THE UPPER LOW MOVES FARTHER TOWARDS THE EAST AND RIDGING OVERRIDES THE REGION. A COLD FRONT MAY NEAR FROM THE NORTHWEST SOMETIME ON TUESDAY. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. SOME SCT-BKN CLOUDS ASSOCIATED WITH LOPRES IN THE SRN MID ATLANTIC WILL IMPACT AREAS THROUGH SOUTHERN NJ AND THE SOUTHERN DELMARVA THIS MRNG, INCLUDING KACY AND KMIV, BUT ANY CIGS WILL BE IN VFR RANGE. NO FLIGHT RESTRICTIONS EXPECTED THIS AFTN AND EVE. EASTERLY FLOW 5-10 KT WILL DEVELOP TODAY. THERE IS STILL A POTENTIAL FOR LOW CLOUDS AND/OR FOG TO DEVELOP NEAR ACY/MIV AFTER 06Z TONIGHT UNDER THE INFLUENCE OF ONSHORE FLOW. OUTLOOK... WEDNESDAY...CHANCE OF SOME MVFR CIGS SERN AIRPORTS AND TERMINALS WED MORNING. CONFIDENCE NOT HIGH. PRIMARILY VFR ELSEWHERE. WEDNESDAY NIGHT - THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS A SERIES OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY FLIGHT MVFR RESTRICTIONS POSSIBLE. FRIDAY THROUGH SATURDAY...PREDOMINATELY VFR CONDITIONS. && .MARINE... THE PRESSURE GRADIENT BETWEEN WEAK HIPRES OVER NEW ENGLAND AND LOPRES MOVING OFF THE VA-NC COAST WILL TIGHTEN TODAY. EASTERLY WINDS WILL STRENGTHEN AS A RESULT LATER THIS MORNING AND AFTERNOON. THE STRONGEST WINDS WILL BE IN THE COASTAL DE WATERS, WHERE WINDS INCREASE TO AROUND 15-20 KT. WINDS GRADUALLY SUBSIDE TONIGHT AS THE LOW PULLS AWAY. OUTLOOK... WEDNESDAY - THURSDAY...ONSHORE FLOW CONTINUES BUT WILL WEAKEN OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY. FRIDAY - SATURDAY...SUB SMALL CRAFT ADVISORY WINDS EXPECTED. THE PERSISTENT ONSHORE FLOW MIGHT BRING SEAS TO SMALL CRAFT ADVISORY LEVELS FRIDAY AND POSSIBLY MORE LIKELY ON SATURDAY. && .RIP CURRENTS... EASTERLY FLOW CONTINUES TO STRENGTHEN THIS MORNING AND 10 SECOND SWELLS HAVE BEEN REPORTED FROM BUOY 44009. THESE CONDITIONS WILL PRODUCE A MODERATE RISK OF RIP CURRENTS FOR THE NEW JERSEY BEACHES AND LOW FOR DELAWARE BEACHES TODAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...HEAVENER NEAR TERM...KLEIN/KLINE SHORT TERM...KLEIN LONG TERM...HEAVENER AVIATION...HEAVENER/KLEIN/KLINE MARINE...HEAVENER/KLEIN RIP CURRENTS...KLEIN

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