Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 291846 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 246 PM EDT SAT AUG 29 2015 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO BECOME CENTERED OFFSHORE TODAY. MEANWHILE, A WEAK DISTURBANCE IS EXPECTED TO MOVE ACROSS THE NORTHEAST ON SUNDAY. HIGH PRESSURE OVERALL THOUGH WILL TEND TO DOMINATE OUR WEATHER THROUGH MUCH OF NEXT WEEK, THEN A WEAK COLD FRONT MAY SLIDE INTO OUR REGION ON THURSDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... HIGH PRESSURE AT THE SURFACE ACROSS THE AREA WILL CONTINUE TO BECOME MORE CENTERED OFFSHORE, AND THIS WILL MAINTAIN A SOUTHERLY FLOW REGIME. MEANWHILE, A SHORT WAVE TROUGH FROM THE MIDWEST TO THE UPPER GREAT LAKES WILL GRADUALLY SHIFT EASTWARD. OUR WEATHER THROUGH TONIGHT WILL BE MAINLY DOMINATED BY THE DEPARTING SURFACE HIGH, THEREFORE A DRY NIGHT IS ANTICIPATED. THE CUMULUS THIS AFTERNOON IS EXPECTED TO FLATTEN AND DISSIPATE THIS EVENING WITH THE LOSS OF HEATING, THEN MOSTLY SOME HIGH LEVEL CLOUDINESS AROUND AT TIMES. THE LIGHT ENOUGH FLOW COMBINED WITH AMPLE BOUNDARY LAYER HEATING THIS AFTERNOON RESULTED IN A SEA BREEZE. THIS WILL CONTINUE TO MOVE INLAND SOME BEFORE WASHING OUT EARLY THIS EVENING. THE SOUTHERLY FLOW HAS HELPED TO INCREASE THE SURFACE DEW POINTS SOME, ALTHOUGH SOME LOWERING IN SPOTS HAS BEEN NOTED THIS AFTERNOON DUE TO BOUNDARY LAYER HEATING AND SOME MIXING. THESE SHOULD EDGE UP A BIT THROUGH THE NIGHT AS COOLING OCCURS AND THE MOISTURE STARTS TO POOL CLOSEST TO THE SURFACE. THIS COULD ALSO LEAD TO GROUND FOG IN LOCALIZED SPOTS. AS FOR THE LOW TEMPERATURES, WE USED MAINLY A NAM/GFS MOS BLEND AND THESE ARE A LITTLE HIGHER OVERALL WITH THE EXPECTATION THAT THE DEW POINTS WILL BE HIGHER THAN PREVIOUS NIGHTS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/... A SHORT WAVE TROUGH IS FORECAST TO BE ARRIVING ACROSS THE NORTHEAST LATER SUNDAY, AND AS IT DOES IT SHOULD TEND TO WEAKEN. A WEAK COLD FRONT AT THE SURFACE IS TIED TO THIS FEATURE, AND WITH SOME MOISTURE ON THE INCREASE THERE SHOULD BE SOME SHOWERS AND THUNDERSTORMS WITH IT TO OUR WEST. THE QUESTION IS WHETHER THIS ACTIVITY CAN BE MAINTAINED AS IT APPROACHES OUR WESTERN ZONES MAINLY LATER IN THE AFTERNOON. THERE IS SOME INSTABILITY DURING THE DAY AND INTO THE EVENING, WITH THIS PROBABLY BETTER ACROSS THE WESTERN ZONES. HOWEVER, THE FORECAST SOUNDINGS MOSTLY SHOW A SKINNY CAPE PROFILE WHICH TENDS TO KEEP UPDRAFTS ON THE WEAKER SIDE. THE BULK OF THE LIFT ASSOCIATED WITH THE TROUGH AXIS IS FORECAST TO BE TO OUR WEST DURING PEAK HEATING, HOWEVER TERRAIN INFLUENCES AND A WEAK SURFACE TROUGH COULD COME INTO PLAY AND THEREFORE WE INCLUDED A SLIGHT CHC POP DURING THE AFTERNOON ACROSS THE NORTHWESTERN ZONES. IT WILL BE RATHER WARM TO HOT ACROSS MUCH OF THE CWA, HOWEVER DEW POINTS MAY BE HIGHER IN THE MORNING DUE TO HEATING OF THE BOUNDARY LAYER ALLOWING FOR SOME DECREASE IN THE AFTERNOON. THE PRESSURE GRADIENT IS NOT FORECAST TO BE ALL THAT TIGHT, THEREFORE LIGHT ENOUGH FLOW SHOULD RESULT IN A SEA BREEZE ONCE AGAIN IN THE AFTERNOON. AS FOR THE HIGH TEMPERATURES, WE USED AN EVEN MOS BLEND THEN MADE SOME LOCAL TWEAKS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... THE LONG TERM ISN`T MUCH MORE EXCITING THAN THE SHORT OR NEAR TERM, WITH HIGH PRESSURE MOSTLY THE DOMINANT FEATURE THROUGH THE NEXT WEEK. SUNDAY NIGHT...A WEAK UPPER LEVEL SHORT WAVE TROUGH WILL CROSS THE REGION, BUT IT SHOULD BE FILLING AND WEAKENING AS IT DOES SO. THUS, CHANCES FOR ANY PRECIPITATION IN OUR AREA ARE SLIM, SO HAVE KEPT THE PERIOD DRY. MONDAY THROUGH TUESDAY...HIGH BUILDS FURTHER EAST THROUGH THIS TIME, WITH THE RIDGE AXIS OVER THE REGION BY TUESDAY EVENING. THE SHORT WAVE TROUGH THAT EARLIER MODEL RUNS HAD SHOWN DIGGING THROUGH THE REGION ON TUESDAY EVENING HAS ALL BUT DISAPPEARED, MEANING RAIN CHANCES HAVE ALSO DECREASED. SO HAVE CHANGED THE FORECAST TO HAVE NO MENTION OF SHOWERS THROUGH THIS TIME. WITH THE HIGH BUILDING IN, 1000-500 MB THICKNESSES WILL ALSO INCREASE THROUGH THIS PERIOD, LEADING TO A MODEST WARMING TREND DESPITE THE LACK OF ANY LOW LEVEL WARM AIR ADVECTION. WEDNESDAY THROUGH FRIDAY...WEAK COLD FRONT LOOKS TO SLIDE IN FROM THE NORTH THROUGH THIS TIME. HOWEVER, THE FRONT SHOULD BE SLOWING AS FRONTOLYSIS BEGINS THROUGH THIS PERIOD, SO DO NOT ANTICIPATE AND SIGNIFICANT COOLING TREND. HOWEVER, THE FRONT COULD SERVE AS A FOCUS FOR LOW LEVEL CONFLUENCE LEADING TO SOME RAIN CHANCES THROUGH THIS PERIOD. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF THIS AFTERNOON...VFR WITH SOME CUMULUS AT AROUND 5000 FEET. SOUTH-SOUTHWEST WINDS UP TO 10 KNOTS. A SEA BREEZE SHOULD TURN THE WINDS MORE SOUTH OR SOUTH-SOUTHEAST AT KACY, WITH THIS ALSO OCCURRING AT KILG DUE TO A BAY BREEZE. TONIGHT...VFR OVERALL WITH REMAINING CUMULUS DISSIPATING IN THE EVENING. THERE IS A CHANCE FOR LOCALIZED MVFR FOG TOWARD SUNDAY MORNING. WINDS BECOMING LIGHT SOUTHWEST OR LIGHT AND VARIABLE AT MOST TERMINALS, TO LOCALLY CALM. SUNDAY...PERHAPS LOCALIZED MVFR FOG EARLY, OTHERWISE VFR WITH SOME CUMULUS AROUND 5000 FEET. SOUTHWESTERLY WINDS INCREASING UP TO 10 KNOTS, WHICH SHOULD TURN MORE SOUTHERLY AT KACY AND PERHAPS KILG DUE TO A SEA/BAY BREEZE. OUTLOOK... SUNDAY NIGHT THROUGH TUESDAY...MOSTLY VFR CONDITIONS EXPECTED, LOCALIZED MVFR POSSIBLE WITH BR EACH MORNING. WEDNESDAY...MOSTLY VFR CONDITIONS EXPECTED, ISOLATED THUNDERSTORMS POSSIBLE LATE IN THE DAY. && .MARINE... HIGH PRESSURE BECOMING MORE CENTERED OFFSHORE WILL ALLOW FOR A SOUTHERLY FLOW THROUGH SUNDAY. WHILE THE WIND SPEEDS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA, SOME INCREASE IS EXPECTED THROUGH THIS EVENING MOSTLY DUE TO A SEA BREEZE INFLUENCE NEARSHORE. THIS MAY ALSO OCCUR AGAIN SUNDAY AFTERNOON. SEAS MAINLY 3 FEET OR LESS. OUTLOOK... SUNDAY NIGHT...A FEW GUSTS NEAR OR ABOVE 20 KT POSSIBLE IN THE EVENING, OTHERWISE WINDS AND SEAS SHOULD STAY BELOW SMALL CRAFT ADVISORY CRITERIA. MONDAY THROUGH WEDNESDAY...WINDS AND SEAS SHOULD STAY WELL BELOW SMALL CRAFT CRITERIA. && .RIP CURRENTS... A LONG PERIOD /AROUND 11 SECONDS/ EAST-SOUTHEAST SWELL CONTINUES INTO TONIGHT, WITH SEAS IN THE 2-3 FOOT RANGE. A FULL MOON /HIGHER TIDE LEVELS/ AND A SOUTHERLY WIND WILL ALLOW FOR TRICKY CONDITIONS AT TIMES IN THE SURF ZONE ESPECIALLY FOR NEW JERSEY. AS A RESULT A MODERATE RISK OF DANGEROUS RIP CURRENTS ALONG THE NEW JERSEY COAST CONTINUES THROUGH THIS EVENING, HOWEVER A LOW RISK IS MAINTAINED FOR THE DELAWARE BEACHES. OUTLOOK... SUNDAY...APPEARS TO BE LOW ENHANCED WITH RESIDUAL IMPACT FROM TODAYS 3 FT 11-12 SECOND SE SWELL BUT THE SWELL SHOULD BE SUBSIDING SOMEWHAT ON SUNDAY. STILL FULL MOON IMPACT SO LARGER THAN NORMAL TIDAL EXCHANGE. MONDAY AND ONWARD FOR NEXT WEEK...CURRENTLY LOOKING TO BE A DAILY LOW RISK. CONCERN: ABOVE NORMAL SST`S (UPPER 70S) AND ABOVE NORMAL TEMPS THIS LAST FULL WEEK OF SUMMER AND FOLKS BEING TOO CASUAL SINCE THE RC RISK IS LOW. FOR GREATEST SAFETY... SWIM IN THE PRESENCE OF LIFE GUARDS AND DURING THEIR COVERAGE HOURS. SWIMMING AT JETTIES, PIERS, GROINS IS ILL ADVISED SINCE RC REPEATEDLY FORM THERE. SWIMMING AT NIGHT OR NOT IN SIGHT OF LIFE GUARDS IS RISKY. WATER TROUBLE CAN QUICKLY TURN TO RECOVERY INSTEAD OF RESCUE. && .CLIMATE... WE HAVE LOOKED AT RECORDS FOR NEXT WEEK (NEAR 100F IN 1953) AND SO WHILE CONFIDENCE IS VERY HIGH IN A HEAT WAVE OCCURRING NEXT WEEK, NOT ENOUGH HEAT IS INDICATED TO CHALLENGE THE RECORDS. RECORD HIGHS NEXT FRIDAY, SATURDAY AND SUNDAY ARE LOWER BUT NOT SURE IF ONSHORE FLOW PREVAILS, THEREFORE KEEPING IT COOLER THAN RECORD. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...GORSE/JOHNSON NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...DRAG/JOHNSON AVIATION...GORSE/JOHNSON MARINE...JOHNSON/NIERENBERG RIP CURRENTS...DRAG/GORSE CLIMATE...DRAG

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