Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 192015 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 315 PM EST Sun Nov 19 2017 .SYNOPSIS... Low pressure over southeast Canada will continue to lift to the north and east tonight. Meanwhile, high pressure over Texas builds east through the Gulf Coast states and will move off the Mid-Atlantic coast Monday night. A cold front approaches Tuesday night and passes through the region on Wednesday. At the same time, low pressure over the Southeast approaches the Mid- Atlantic and moves out to sea. High pressure builds through the region to close out the week. A cold front passes through the region Saturday, then low pressure will be over eastern Canada over next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Strong northwest flow continues across the area between an area of low pressure to our northeast across southeastern Canada, and high pressure to our southwest across the Lower Mississippi Valley. This tight pressure gradient will continue through tonight and will keep winds elevated overnight. However, wind gusts will continue to diminish this evening, and may drop off for many locations overnight. With the northwest flow, clouds will continue to to be trapped under inversion around 4,000-6,000 feet and remain across most of the area. The thickest clouds cover will be from the I-95 corridor northward. A short wave/vorticity impulse and an area of enhanced low level lift and moisture will move across the northern half of the area later this evening and overnight. The combination of the lift and moisture associated with the short wave/vorticity impulse may be enough that may help any lake effect streamers within the northwest flow may make their way into portions of our area overnight. There will be a slight chance of isolated snow showers/flurries later tonight for areas along and north of the I-78 corridor. The Poconos may have the better shot of seeing any accumulation if any showers do occur. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... Monday is expected to be a fairly nice day. The pressure gradient relaxes some during the day as high pressure builds to our south, but there will remain a steady breeze through the day. Also, winds will be gusty around 20-25 mph through much of the day as well, but much less windy than Sunday. There will remain some scattered cloud cover across the area, especially in the morning hours and areas along and north of the I-95 corridor. Skies are expected to begin to clear out by he afternoon. No precipitation is expected through the day on Monday as any lake effect streamers will get cut off or push north of our area as the flow turns more west to southwesterly through the day and moisture/lift becomes limited as well. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... High pressure over the Mid-Atlantic moves out to sea Monday night and will be off the Mid-Atlantic coast on Tuesday. Return flow sets up, and highs on Tuesday will be about 3-5 degrees above normal, topping off in the 40s in the Poconos, otherwise in the low to mid 50s north and west of I-95, and near 60s in the Delmarva and southern NJ. S to SW winds increase Tuesday afternoon to 15-20 mph with gusts up to 30 mph. High pressure moves out to sea late Tuesday as a cold front moves through the Great Lakes and Ohio Valley. Meanwhile, low pressure develops over the Gulf Coast on Tuesday, and that low moves off the Southeast U.S. coast Tuesday night. Tuesday night through Wednesday morning, that low approaches the Mid-Atlantic coast and drifts out to sea. That cold front will pass through the region Wednesday afternoon. Based on latest model guidance, will carry a swath of likely PoPs across southern DE and southeast NJ, and chance PoPs for most areas south and east of the Fall Line. Cooler temps will move into the Poconos Wednesday afternoon, but stronger CAA will not be underway until Wednesday night. Chilly high pressure builds through the region Thanksgiving Day with temperatures 6-8 degrees below normal. Highs top off in the mid and upper 30s in the Poconos, otherwise in the low to mid 40s. High pressure reestablishes itself over the area Friday with highs a few degrees warmer than Thursday. Low pressure passing well north of the region will drag a cold front through the region on Saturday, and then low pressure remains over eastern Canada through next weekend. Unsettled weather possible. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR conditions expected. Slight chance of an isolated snow shower overnight for ABE and RDG, which may briefly lower conditions if any showers occur. Winds remain gusty into this evening, then gusts drop off overnight, although a steady breeze will remain. High confidence in VFR conditions. Low confidence in showers. High confidence in winds. Monday...VFR conditions expected. Winds expected to increase and become gusty again later in the morning and through the day. High confidence in VFR conditions and winds. Outlook... Monday night through Tuesday...VFR. SW winds 5-10 KT Monday night increase to 15-20 KT with gusts up to 25 KT Tuesday afternoon. Tuesday night and Wednesday...Mainly VFR. Rain possible south and east of I-95 Tuesday night through Wednesday morning with MVFR or lower conditions. SW winds 5-10 KT become NW Wednesday afternoon and increase to 10-20 KT. Wednesday night and Thursday...VFR. NW winds gradually diminishing. A storm system is currently expected to remain offshore. Forecast confidence: Medium to High. Friday...VFR. NW winds 5-10 KT. && .MARINE... A Gale Warning is in effect for all areas through tonight. Winds are expected to diminish through the night, and should fall below gale force by daybreak Monday. Then Small Craft Advisory level conditions will likely continue through the day Monday. Outlook... Monday night through Tuesday night...Brief lull in SCA conditions late Monday night through Tuesday morning. Otherwise, 25-30 KT wind gusts, primarily on the ocean waters, may possibly over Lower DE Bay Tuesday afternoon. Wednesday...Lull in SCA conditions possible Wednesday morning. Otherwise, winds shift to the NW and increase to 15-20 KT with 25-30 KT gusts. Thursday through Friday...Sub-SCA conditions expected. && .TIDES/COASTAL FLOODING... There is a potential for blow out tides this evening, mainly for the Upper Delaware Bay. We will maintain the Low Water Advisory as it is with no extension in time, or expansion in area. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Gale Warning until 5 AM EST Monday for ANZ430-431-450>455. Low Water Advisory until 7 PM EST this evening for ANZ430. && $$ Synopsis...MPS Near Term...Robertson Short Term...Robertson Long Term...MPS Aviation...Robertson/MPS Marine...Robertson/MPS Tides/Coastal Flooding... is the U.S. government's official web portal to all federal, state and local government web resources and services.