Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
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800 FXUS61 KPHI 291936 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 336 PM EDT Wed May 29 2024 .SYNOPSIS... A weak cold front passes offshore tonight and may stall some thereafter. High pressure builds in Thursday and holds dominate influence over the region into Sunday. Unsettled conditions could return by late Sunday and continue into the middle of next week. && .NEAR TERM /THROUGH THURSDAY/... Latest radar imagery shows scattered showers and isolated thunderstorms beginning to enter the forecast area. Expecting to see coverage increase through the afternoon and into the evening as a weak surface low shifts across the state of PA. In terms of the severe potential...mesoanalysis shows SBCAPE values reaching around 500 J/kg across the Delmarva and eastern PA at the moment with hi res guidance suggesting values to reach into the 1000 J/kg range in some locations, which could help fuel some gusty winds and heavier downpours. Deep layer 0-6km shear values will be best across the southern Delmarva, but the shear profiles will be largely unidirectional or incoherent and not favorable for severe development. In terms of flooding concerns...rainfall forecast amounts have increased slightly overall with areas across northeast PA and northern NJ around 0.50-1.00 inches with locally higher amounts possible. While areas south of I-78 will see storms progress a bit more with embedded downpours, areas along and north of the interstate could see some steady moderate rainfall train across the region beginning this evening and into tonight with some heavier pockets at times. That said, some localized flooding may be possible later this evening and into the late night hours as this storm slowly shifts offshore. Overnight lows will be in the mid 50s. Skies will be mostly cloudy and begin to clear towards sunrise early Thursday morning. Some showers may linger across eastern NJ prior to sunrise. Thursday looks to stay mostly dry, though a few isolated showers and possibly a thunderstorm could develop in the afternoon as our mid level trough remains over head. A weak shortwave will pivot around the main trough and provide some weak and broad ascent across our forecast area. While the best forcing will be south of the region, we can`t rule out a few isolated showers across NJ and parts of the Delmarva. That said, dew points at the surface will be in the upper 40s to low 50s and some showers may not reach the ground. Otherwise, mostly sunny with highs around the low to mid 70s. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... The region will feel the influence of surface high pressure throughout the duration of the short term. Surface high pressure centered to our west Thursday night will gradually move eastward with time. This surface high pressure will look to be centered over the region for Saturday. With surface high pressure in control of the region, expect a nice and quiet short term with pleasant conditions. Some lingering shortwave energy could persist into the first half of Thursday night; a quick and isolated pop-up shower cannot be ruled out entirely, but overall things will be quiet for the period. Friday and Saturday will be beautiful sunny and dry days with surface high pressure in control. We are looking at highs in the 70s Friday with dewpoints in the 40s. For Saturday, we are looking at highs near 80F with dewpoints mainly in the 40s. Both days will feel very comfortable; being outdoors will be enjoyable. Mainly clear skies will be present Thursday night and Friday night with light winds in the forecast. Decent radiational cooling will likely occur both nights. Overnight lows in the low to mid 50s can be anticipated both nights. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Ensembles and deterministic models suggests a more zonal upper-level pattern will take hold over the CONUS for long term. At the surface level, guidance suggests surface high pressure will continue to hold influence over the region Saturday night into Sunday while continuing to move eastwards/southeastwards and offshore. As the high shifts further offshore of the eastern CONUS with time Sunday into Tuesday, some weak low pressure, associated fronts, and shortwave energy could be invited to influence the region later Sunday into next week. Overall, things could generally become unsettled again Sunday afternoon onwards. Not much confidence in details of the long term forecast today with the forecast zonal upper-level pattern and its slow evolution. Expect unsettled conditions Sunday afternoon onwards with chances for showers and thunderstorms in the afternoons/evenings. && .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas... Rest of today (through 00Z)...VFR conditions overall. SHRA will become likely this afternoon and into this evening, but confidence is low that sub- VFR conditions will occur in any SHRA at any given time. For now, will mention -SHRA in the TAF, but will keep conditions VFR. A few TSRA possible as well, but confidence is even lower that a given TSRA will pass over a given terminal. Still will place a VCTS in the forecast, however. W-NW winds 5-10 kt. Low confidence on timing of potential restrictions. Tonight...Once again, VFR overall, but potential for sub-VFR in any SHRA or even TSRA passing over a given terminal. Will leave out of TAF for now due to low confidence. Also the potential for sub- VFR CIGs after 06Z at any terminal where it rains. N-NW winds around 5 kt. Low confidence. Thursday...Mainly VFR expected. Sub-VFR conditions possible in the afternoon for I-95 terminals and east with a slight chance (15-25%) for a quick shower or a thunderstorm. NNW winds 5-10 kts. Moderate confidence. Outlook... Thursday night through Saturday night...VFR. High confidence. Sunday...Mainly VFR. Sub-VFR cigs could develop for some sites by the afternoon. Moderate confidence. Monday...Mainly VFR, though some sub-VFR cigs could linger. Moderate confidence. && .MARINE... Sub-SCA conditions through Thursday. Light southerly winds this afternoon around 10kts will shift W-WNW overnight. Showers and a few thunderstorms possible with a surface low moving east tonight and out to sea early Thursday. Winds shift N-NE around 10 kts during the day Thursday. Seas will linger around 2-3 feet. Outlook... Thursday night through Monday...No marine headlines anticipated. Rip Currents... West to northwest winds at 5 to 10 mph this morning will become south by this afternoon. Breaking waves will average 1 to 2 feet. There is a LOW risk for the development of dangerous rip currents for the New Jersey and Delaware beaches. For Thursday, west to northwest winds 5 to 10 mph will turn north in the afternoon. Breaking waves will once again average 1 to 2 feet. Therefore, there will continue to be a LOW risk for the development of dangerous rip currents for the New Jersey and Delaware beaches. For specific beach forecasts, visit weather.gov/beach/phi As always, rip currents can still develop, and often occur in the vicinities of jetties and piers. Utilize any guarded beaches if venturing out into the water. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...Wunderlin NEAR TERM...MJL SHORT TERM...Wunderlin LONG TERM...Wunderlin AVIATION...MJL/Wunderlin MARINE...MJL/Wunderlin