Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 221354 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 954 AM EDT Tue May 22 2018 .SYNOPSIS... A warm front will lift across the area today into this evening as an area of low pressure lifts across the Great Lakes region and into New York state. A cold front will then move across the area tonight into Wednesday morning. High pressure will build across the area Thursday, then offshore Friday. A backdoor cold front is forecast to move southward across the area late Saturday, while a warm front may lift into the area Saturday as well. These fronts may stall near the area into early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A warm front extended from the eastern Great lakes, across central Pennsylvania to the Chesapeake Bay area this morning. The boundary will progress slowly to the northeast and it should move into our region for this afternoon. We continue to expect rain showers. Also, conditions will destabilize this afternoon on the warm side of the front. Mixed layer CAPE values are anticipated to reach 500 to 1000 J/Kg on the upper Delmarva. We will continue to mention scattered thunderstorms for this afternoon. Even in the northeastern part of our forecast area where conditions will remain fairly stable near the surface, there may be enough instability aloft to result in some thunder. A southeast to south wind around 5 to 10 MPH is expected. Maximum temperatures will range from the 60s in the Poconos and in northern New Jersey to the upper 70s in southern Delaware and in the adjacent counties of eastern Maryland.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... The low to the north will pull away and begin to move down the St. Lawrence valley tonight. An associated cold front will begin to approach the area. This will bring a continuation of the unsettled conditions from the daytime. More showers and sct tstms will be around, mostly during the evening and early overnight periods. Again local downpours and gusty winds with ant tstm. The higher pops will be across srn NJ and Delmarva. It will remain warm and humid tonight with lows only dropping into the low/mid 60s in most areas and some 50s across the far N and NW. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Quiet conditions start off the extended period, then unsettled forecast returns by the weekend into early next week, although there is some uncertainty. On Wednesday, the cold front will continue to push to our east early in the day, so there may still be some lingering showers very early in the day. However, as the front continues to push southward, the showers should end by midday and dry weather will move into the area into Wednesday night. High pressure will build across the area on Thursday, before pushing offshore Friday. This will provide dry weather, with warming temperatures. Then the uncertainty begins to build across the area over the weekend into early next week. High pressure remains offshore Saturday, which will keep strong return flow across the area, leading to another day of warmer than normal temperatures. Then a backdoor cold front is forecast to advance southward toward the area later Saturday evening. Meanwhile, a warm front could be lifting northward into the area from the south as well. The fronts would merge into one stationary frontal boundary and linger near the area into early next week. As multiple short wave/vorticity impulses move across the area over the weekend into early next week, this could lead to several periods of unsettled weather from late Saturday through at least Monday. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/...
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The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...A warm front approaching from the west and south will bring lowering CIGS and increasing chcs for showers and a few tstms today. The CIGS will lower earlier and lowest N/W and later higher S/E. The exact timing of the lower conditions is a bit uncertain. Winds will be rather light today from the SE or S. Tonight...Low conditions continue with more showers. IFR or low end MVFR will predominate with showers and sct tstms continuing. It`s possible that conditions may improve late tonight N/W, but this is still rather uncertain with the models showing the front moving a bit slower than before and it may not clear the N/W areas until after 12Z. Winds again, rather light from the S or SE overnight. OUTLOOK... Wednesday-Wednesday night...Becoming VFR. Showers possible early. NW winds may gust around 15-20 knots in the afternoon. Thursday-Thursday night...VFR. N winds may gust around 15-20 knots at times during the day. Friday-Saturday...VFR. Southwest winds may gust 15-20 knots during the day. Showers possible late Saturday.
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&& .MARINE...
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Overall, sub-SCA conditions are expected across the waters today. An increasing wind today with directions SE early then S during the afternoon. The direction will continue to veer to SW tonight. Scattered showers and a few tstms are expected. Locally higher winds and seas near tstms can be expected. Seas on the ocean will mostly be 2 to 3 ft today and tonight. OUTLOOK... Wednesday-Thursday night...Sub Small Craft Advisory conditions expected. Friday-Saturday...Winds and seas begin to increase and may approach Small Craft Advisory levels.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...Robertson Near Term...Iovino Short Term...O`Hara Long Term...Robertson Aviation...Robertson/O`Hara Marine...Robertson/O`Hara

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