Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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285 FXUS61 KPHI 261913 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 313 PM EDT Wed Apr 26 2017 .SYNOPSIS...
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A weakening coastal low near Long Island will move slowly northeast overnight. A cold front will move across the area late Thursday night and early Friday morning before another cold front crosses Saturday night. A warm front is then expected to lift north across the area Sunday night, followed by another cold front Monday night. High pressure is then expected for the middle of next week.
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&& .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Rest of today...ceilings slowly lifting with some breaks in overcast or brightening and temps ever so slowly warming as the vertically stacked low pressure system off the NJ coast heads east. There may still be some spotty mist or an isolated shower/ sprinkle into this evening, mainly ne NJ. Tonight....where it clears...fog may form right away...otherwise a deck of clouds may persist much of the night near 2000 or 3000 ft that would prevent significant fog and stratus formation during the night. Confidence on stratus fog formation, expansion/reformations is below average but we have maintained it in the fcst..using the UPS crossover tool. Fcst was was a 50 50 blend of the 12z/26 GFS/NAM mos. Fcst mins are 8 to 12 degrees above normal. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... Mostly cloudy to start...but all model tsections fcst a much brighter and warmer day... so used the 12z/26 gfs/nam mos blend for the fcst basis. Fcst temps are 7 to 13F above normal. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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A cold front associated with low pressure moving north through eastern Canada is expected to cross the region Thursday night, then move off the coast Friday morning. Mainly scattered showers are expected at this time, primarily from midnight through 6 or 7 AM. A southerly flow aloft will maintain low temperatures in the mid to upper 40s and high temperatures in the upper 70s to low 80s, above normal for this time of year. The daytime hours on Friday will feature mainly dry weather has high pressure briefly builds into the region. By Friday night, another frontal boundary is forecast to begin approaching the area from the northwest as it crosses Pennsylvania and New York. The front will sag south through the area during the day Saturday, bringing with it some additional shower activity, then stall to our south Saturday night into Sunday. The subsequent onshore flow will cool temperatures down to the 60s north and low 70s south on Sunday,but with mainly dry conditions. This front is then expected to lift back north as a warm front Sunday night into Monday morning, with an increasing chance of showers as the day wears on with the approach of a cold front from the west late in the day. Showers and thunderstorms may accompany this front...especially later Monday night into Tuesday morning. Instability in the warm sector ahead of this front could even produce shower and thunderstorm activity as early as Monday afternoon. High temperatures in the 70s are expected on Monday. The front will move offshore by Tuesday morning, but a secondary surface trough may move across the area during the day. With a short wave/vorticity max moving across the area during the day, there could be some isolated showers across northeastern Pennsylvania and northern New Jersey. Cooler temperatures are expected through mid week, with lows generally in the 50s and highs in the 70s.
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&& .AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Rest of this afternoon...Cigs 800 to 1800 feet continue to improve- rise with a few remaining patches of IFR drizzle, mainly NNJ. Probably goes MVFR to possibly VFR cigs by 22z most everywhere. Light north to northeast wind. Tonight...Probably MVFR cigs to start but may deteriorate to IFR conditions in st/fog with a nearly calm wind sometime between 06z and 12z/27. Please see TAFS for details. Thursday...Ifr or MVFR conds in st/fog to start the day, probably improves to VFR sct-bkn clouds aoa 3500 feet during the afternoon. Wind becoming southeast to south. OUTLOOK... Thursday night...Generally VFR. A chance of showers overnight which could temporarily reduce conditions to MVFR. Friday...VFR conditions expected. Friday night...VFR early. Patchy fog and low CIGS may develop overnight. Saturday...Becoming VFR during the morning, then a chance of showers during the afternoon. Conditions may temporarily be reduced with any showers. Saturday night-Monday...Low clouds and fog may develop overnight Saturday and continue into Sunday leading to reduced conditions. There will also be a chance of showers.
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&& .MARINE...
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The Small Craft Advisory hazardous seas continues through Thursday. Waves are currently around 7 ft and will gradually subside through Thursday. A question becomes: how much marine fog develops the next day or so. OUTLOOK... Thursday night...Small Craft Advisory for hazardous seas through Thursday night. Friday...Winds expected to remain below advisory levels, but seas may remain elevated to advisory levels. Friday night-Monday...Winds are expected to remain below advisory levels. Seas may approach 5 feet at times, but mostly remain around 4 feet.
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&& .TIDES/COASTAL FLOODING... Tides fcst near advisory threshold this evening. Holding off on an advisory for now but may need to issue for minor coastal flooding around 6 or 7PM if departures do not further decrease. We will continue to monitor the high tide this evening since it will be the higher one that occurs with a new moon. If the water does not drain away from the coast fast enough, we could see some localized minor flooding at that time. && .CLIMATE... Presuming our forecast temps these last 5 days of April are accurate, we are assured of a top 3 warmest April on record in much of our forecast area. Sunday is the critical day for determining record or not. Below: April projected within the top April avg temps, the normal for April and the period of record (POR). PHL normal 54.0 POR 1874 59.4 1994 59.2 2017? 58.5 1921 58.4 2010 57.9 1941 ABE normal 49.9 POR 1922 56.6 projecting record 56.4 1941 54.7 1994 ACY normal 51.7 POR 1874 57.2 projecting record 56.3 2010 56.1 2011 && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT Friday for ANZ450>455. && $$ Synopsis...Miketta Near Term...Drag Short Term...Drag Long Term...Miketta Aviation...Drag/Miketta Marine...Drag/Miketta Tides/Coastal Flooding...Drag Climate...Drag

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