Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 040058 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 858 PM EDT FRI JUL 3 2015 .SYNOPSIS... A WEAK HIGH PRESSURE SYSTEM WILL REMAIN OVER NEW ENGLAND TONIGHT, BEFORE MOVING OFFSHORE ON SATURDAY. MEANWHILE, LOW PRESSURE OVER THE OHIO VALLEY WILL MOVE ALONG A STALLED FRONTAL BOUNDARY TO OUR SOUTH AND PASS EAST OF THE DELMARVA PENINSULA ON INDEPENDENCE DAY. ANOTHER AREA OF HIGH PRESSURE WILL THEN MOVE INTO THE REGION FOR THE END OF THE HOLIDAY WEEKEND AND MONDAY. A WEAK LOW PRESSURE SYSTEM MIGHT EASE NORTH INTO THE AREA ON TUESDAY AS ANOTHER COLD FRONT APPROACHES THE FORECAST AREA BY MIDWEEK. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... WILL BEGIN THE NIGHT WITH STILL RATHER PLEASANT CONDITIONS AS THE HIGH CONTINUES TO SLIDE AWAY FROM THE REGION. WILL LIKELY NOT BEGIN TO SEE THE EFFECTS OF THE APPROACHING LOW UNTIL AFTER MIDNIGHT. ONE THING WE`LL BE WATCHING CLOSELY IS THE LOW LEVEL WINDS OVERNIGHT. LOW AND MID LEVEL FLOW TODAY ENDED UP BEING CONSIDERABLY LIGHTER THAN WAS PREVIOUSLY FORECAST, NOT TO MENTION THAT WIND DIRECTION AT THE SURFACE WAS VARIABLE FOR MUCH OF THE DAY. THUS, RELATIVELY DRY AIR REMAINS IN PLACE IN THE BOUNDARY LAYER. AS A RESULT, EVEN THOUGH WE MAY HAVE THE BEST SYNOPTIC SCALE LIFT IN PLACE BY 12Z, START OF RAIN (OR AT LEAST INCREASE IN INTENSITY OF RAIN) MAY BE DELAYED BY A FEW HOURS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... STILL LOTS OF UNCERTAINTY IN THIS PERIOD. THERE IS CONSIDERABLE DISAGREEMENT BETWEEN MODELS AND RUN-TO-RUN ON INDIVIDUAL MODEL RUNS. FOR THE MOST PART, THE MAIN DETERMINISTIC MODELS HAD A SLIGHTLY DRIER TREND WITH THE 12Z RUNS. HOWEVER, THIS HAS BEEN THE CASE THE LAST FEW DAYS, WITH THE 00Z RUNS TENDING TO BE WETTER SOLUTIONS. AT THIS POINT, THINK THE HIGHEST CHANCES WILL STILL COME BEFORE 21Z. THINK THAT IT WILL MOSTLY BE A STEADY RAIN GIVEN A RATHER STABLE ATMOSPHERE IN PLACE. AS FAR AS RAIN AMOUNTS, HAVE FAVORED LIGHTER AMOUNTS GIVEN THE UNCERTAINTY OF HOW MUCH MOISTURE ADVECTION WE WILL HAVE. MOST MODEL SOLUTIONS CONTINUE TO SHOW THE PRECIP LIFTING OUT QUICKLY FROM MID TO LATE AFTERNOON. WITH ALL THE CLOUD COVER IN PLACE, IT LOOKS TO BE A RATHER COOL DAY (HIGHS IN THE 60S AND 70S). && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... ANY LINGERING PRECIP SHUD BE ENDING ERLY SAT EVE WHICH SHUD HAVE A POSITIVE IMPACT ON ANY FIREWORKS DISPLAYS AND OTHER HOLIDAY FESTIVITIES. HIGH PRES WILL THEN BUILD IN FOR SAT NIGHT THRU MON KEEPING THIS PD DRY OVER MOST, IF NOT ALL OF THE AREA. THE ONLY LOCATION THAT GUID IMPLIES CUD SEE SOME PRECIP WUD BE OVER THE DELMARVA COME MON. BY MON NIGHT INTO TUE, ANOTHER QUICK WV MOVES THRU, THEN THE GFS IS MUCH FASTER WITH A CDFNT FROM THE W, BRINGING IT THRU BY WED MRNG AND THE ASSOCD PRECIP. THE CMC AND ECMWF ARE MUCH SLOWER BRING THE FRONT THRU LATER WED INTO WED NIGHT. IF THE EC IS TO BE BELIEVED, WITH THE SLOWER FRONTAL TIMING, TUE NIGHT INTO ERLY WED, CUD BE DRY AND WED CUD BE ON THE HOT SIDE AHEAD OF THE FRONT. THEN THE ECMWF DEVELOPS WHAT APPEARS TO BE A VERY STRONG WAVE FOR FRI THAT THE GFS DOESN`T HAVE, AND IS SUBSEQUENTLY DRY. ONCE AGAIN, CONFIDENCE IS LOWER THAN AVERAGE. THERE WILL BE A CFP. HAVE SHADED THIS FCST TWD THE MDL CONSENSUS AND THE SLOWER TIMING, BUT, NOT SURE ON THE MOST LIKELY PDS OF PRECIP AS A RESULT OF THE UNCERTAINTY. FOR NOW, AM JUST CARRYING LOW POPS FOR FRI, AS WE HAVE A WEEK TO SEE WHAT, IF ANYTHING, DEVELOPS. TEMPS WILL START OFF NR NRML AND RISE TO ABV NRML VALUES BY THE MIDDLE AND END OF THE WEEK. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT WITH CEILINGS AOA 5,000 FEET. SOME LIGHT RAIN SHOWERS MAY BEGIN TO MOVE INTO THE REGION BY 05Z WITH CHANCES INCREASING FROM SOUTH TO NORTH OVERNIGHT. THE STEADIEST AND HEAVIEST SHOWERS LOOK TO BE FROM 13-18Z SATURDAY, WHICH WILL CORRESPOND TO THE HIGHEST CHANCE FOR MVFR CEILINGS/VSBYS FROM PHL/PNE TO THE SOUTHEAST. RDG AND ABE COULD ESCAPE THE PROSPECTS FOR ANY MVFR RESTRICTIONS. ACY HAS HIGHEST LIKELIHOOD TO SEE MVFR CONDITIONS WITH THE SLOWEST RISE IN CEILINGS LATE IN THE DAY. CEILINGS WILL LIKELY LIFT TO VFR AND BECOME BROKEN BY 19Z OUTSIDE OF ACY WHERE AN ONSHORE FLOW WILL TEND TO KEEP THEM LOWER. WINDS WILL BE AT OR UNDER 10 KNOTS FROM THE SOUTH LATE THIS EVENING THEN SHIFTING TO EASTERLY FOR MOST OF SATURDAY. A WIND SHIFT TO A MORE WESTERLY DIRECTION IS LIKELY TO START BY SATURDAY EVENING. OUTLOOK... SAT NIGHT...SOME MVFR FOG PSBL AT THE MORE RURAL ARPTS, OTHERWISE VFR. HIGH CONFIDENCE. SUN THRU TUE NIGHT...VFR SUN AND SUN NIGHT. HIGH CONFIDENCE. VFR MON AND TUE OUTSIDE OF ANY SHRA/TSRA MAINLY IN THE AFTNS. WED...PREDOMINATELY VFR, BUT DECREASING TO MVFR/IFR WITH INCREASING CHCS OF SHRA/TSRA, ESPECIALLY W AS CDFNT APPROACHES. MDT CONFIDENCE. && .MARINE... WINDS AND SEAS SHOULD STAY BELOW SCA CRITERIA TONIGHT INTO TOMORROW MORNING. BY TOMORROW AFTERNOON, WINDS AND SEAS COULD BUILD NEAR 25 KT/5 FT, PRIMARILY ON THE NORTHERN ATLANTIC WATERS. HOWEVER, THERE IS CONSIDERABLE UNCERTAINTY. OUTLOOK... SAT NIGHT AND SUN...THERE IS STILL SOME UNCERTAINTY WITH THE STRENGTH AND TRACK OF THE LOW, BUT IT APPEARS THE BEST CHC OF SEAS ABOVE SCA CONDS WILL BE EARLY SAT NIGHT AND PSBLY SOME MRGNL WIND. HOWEVER, CONFIDENCE IS LOW ENOUGH AT THE MOMENT TO HOLD OFF ISSUING ANY FLAGS ATTM. THE BEST CHCS APPEAR TO BE ON THE NRN WATERS. AFTER ANY SCA LINGERING INTO THE MRNG, THE CONDS SHUD DECREASE BELOW SCA LATER INTO SUN. SUN NIGHT THRU WED...NO MARINE FLAGS ARE ANTICIPATED. && .TIDES/COASTAL FLOODING... WITH CONTINUED WEAK ON SHORE FLOW, HIGH TIDES THIS EVENING AND SATURDAY EVENING COULD APPROACH THE MINOR FLOODING LEVEL, BUT RIGHT NOW NO SITES ARE FORECAST TO REACH LEVELS NEEDED FOR A COASTAL FLOOD ADVISORY. SAT NIGHT AND SUN LOOK TO BE THE SAME WAY. WHILE SOME SITES MAY APPROACH MINOR TIDAL FLOODING LEVELS, CURRENT DATA INDICATES THEY WILL REMAIN BELOW CRITERIA. && .RIP CURRENTS... THERE IS A MODERATE RISK OF RIP CURRENTS INTO THIS EVENING ALONG THE NEW JERSEY SHORE. BY TOMORROW, A MODERATE RISK OF RIP CURRENTS IS LIKELY FOR BOTH NEW JERSEY AND DELAWARE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...NIERENBERG NEAR TERM...JOHNSON SHORT TERM...JOHNSON LONG TERM...NIERENBERG AVIATION...GAINES/JOHNSON/NIERENBERG MARINE...JOHNSON/NIERENBERG TIDES/COASTAL FLOODING... RIP CURRENTS...

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