Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 062327 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 627 PM EST Fri Dec 6 2019 .SYNOPSIS... Low pressure across New England this evening will cause a cold front to cross the Middle Atlantic region. A large area of high pressure from the Great Lakes will build across the area this weekend. Once the high moves away early next week, a series of low pressure systems and fronts will affect the area into the middle of the week. More high pressure with cold air arrives for later next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 630 pm update: Showers are moving steadily through New Jersey at this hour, and have increased PoPs through 8 pm in advance of these. Otherwise, forecast is in good shape. Previous discussion... Cold front is now progressing through PA as the mid and upper level short wave trough digs closer to the region. A few showers continue to be possible late this afternoon into early this evening. Aside from the Poconos, where some snow may mix with rain, for most of the region if we see any precipitation, it should be all rain. As the cold front crosses our region this evening, expect an abrupt shift to northwesterly winds and a brief period of breezy conditions behind the front. Much of the guidance shows winds staying relatively light even behind the front, but expect that the guidance is a bit too fast in showing the development of the nocturnal inversion in the higher elevations of NW NJ and the Poconos. Thus gusts of 20 to 25 mph will be possible in these locations through the evening. Additionally, this is a prime setup for gusty winds on the waters, so coastal locations, and especially locations near the mouth of the Delaware Bay could see wind gusts to 30 mph through the evening. Will likely see cold air advection for much of the night. Thus, expect lows to be slightly lower than this morning, with lows in the 20s (with the exception of Philly and portions of Delmarva where lows could be right around 30). && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... High pressure begins to build in leading to decreasing, but still persistent northwest flow and cold air advection. With the large scale subsidence, should have dry weather and few clouds through the day. Temperatures are expected to be 5 to 10 degrees below normal, with highs in the 30s and lower 40s. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... Saturday night and Sunday will feature nice weather as large high pressure across the region Sunday morning will move offshore Sunday night. Temperatures will be close to average Sunday afternoon after a cold morning. Highs will reach the low/mid 40s across the north and central areas while upper 40s and low 50s will be across the metro areas and Delmarva. Low pressure will advance towards the area early next week. A stream of moisture will develop over the area Sunday night and persist through Monday and beyond. Frequent clouds and rains will be found across the region. The rains and poor weather will continue into Tuesday. It will become unseasonably mild, especially Tuesday when highs will be in the 50s north/west and low 60s for Delmarva and south NJ. QPF for the period could be in the 1 to 2 inch range, so the possibility of some localized poor drainage flooding can`t be ruled out. Also, if temps do not warm quick enough across the north/west areas Sunday night, a little snow at the onset is possible. As the system moves away Tuesday night and Wednesday, colder air will arrive from the N/W. P-type could become an issue again with the rains possibly changing to snow before ending. We`ll have to watch this with the possibility for some accums across the Poconos and north NJ. (other areas possible too). Temps will drop back through the 40s Wed and 30s Wed night. The end of next week will feature dry, but cold weather. Highs Thu will be well below normal with 30s regionwide, some moderation possible Fri. Another system may approach for next weekend with more rains/snows possible. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR with CIGs dissipating by late evening. Southwest winds will become abruptly northwest by 03z across the area, with speeds of 5 to 15 kt. High confidence. Saturday...VFR with northwest winds around or below 10 kt. High confidence. Outlook... Saturday night-Sunday...VFR expected. Increasing clouds Sunday. Sunday night thru Wednesday...Widespread IFR expected with LIFR also possible at times. Rains, low clouds and fog much of the time. Gusty winds expected, especially near the coast. && .MARINE... Gale conditions are expected in the vicinity of Sandy Hook through late this evening, so have issued a gale warning for the coastal waters adjacent to Monmouth County. Otherwise, expect breezy southwesterly winds through early this evening, with SCA conditions expected on the rest of the Atlantic coastal waters. On the Delaware Bay, gusts near 20 kt are expected. Then this evening, a cold front will bring an abrupt shift to northwesterly winds resulting in SCA conditions on the lower Delaware Bay and most of the Atlantic coastal waters, with gales still possible for the Monmouth County coastal waters. Winds should diminish quickly near sunrise, and during the day tomorrow, winds and seas should stay below SCA. OUTLOOK... Saturday night-Sunday night...Sub-SCA. Fair thru Sunday than rains developing Sun night. Monday-Wednesday...Small Craft Advisory conditions likely with Gales possible. Rain and fog much of the time. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 6 AM EST Saturday for ANZ451>455. Gale Warning until midnight EST tonight for ANZ450. Small Craft Advisory until 6 AM EST Saturday for ANZ431. && $$ Synopsis...O`Hara Near Term...CMS/Johnson Short Term...Johnson Long Term...O`Hara Aviation...CMS/O`Hara Marine...Johnson/O`Hara is the U.S. government's official web portal to all federal, state and local government web resources and services.