Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
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831 FXUS61 KPHI 271345 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 945 AM EDT Thu Jun 27 2024 .SYNOPSIS... In the wake of a cold front this morning, high pressure builds toward our area tonight then arrives during Friday before shifting offshore into Saturday. A warm front lifts north across our region Saturday, followed by a cold front during Sunday. High pressure then arrives for Monday and Tuesday before weakening and sliding offshore Wednesday. && .NEAR TERM /THROUGH TONIGHT/... The cold front has mostly moved offshore, although it is still lingering across far southeast New Jersey coast and across southern Delaware. It will continue shift farther offshore through today. Behind it, stratocumulus clouds have begun to develop this morning as morning heating has begun to mix the boundary layer and clouds are forming near the low level inversion. As this inversion mixes and lifts through the morning and this afternoon, the cloud heights will lift. We may end up with partly cloudy skies through the day. Temperatures return to more seasonal levels today, topping off in the mid to upper 80s. Surface dew points will fall into the upper 50s/near 60 during the afternoon as well. High pressure over the Great Lakes this evening begins to build east tonight and tranquil conditions will continue as a result. Lows tonight will generally be in the low to mid 60s. However, in the Lehigh Valley, northwest New Jersey, and southern Poconos, temps look to get down into the mid to upper 50s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... High pressure builds east across the Northeast on Friday then weakens some and shifts offshore into Saturday. Tranquil conditions expected during this time. Sunny and pleasant on Friday with seasonably warm temperatures. Highs will be in the low to mid 80s, though cooler at the coasts and in the mountains. Due to increasing cloud cover, lows will be a few degrees warmer Friday night compared to Thursday night. On Saturday, low pressure will be moving across the Northern Plains and into the northern Great Lakes. A warm front will develop out ahead of this system, and that will lift through the eastern third of the U.S. Saturday afternoon. Surface dew points will rise into the 70s throughout much of the region, and with highs in the 80s, heat index values will be in the low to mid 90s mostly from the I-95 urban corridor southward across our Delmarva counties. Shortwave energy passing through the region will spark off some showers and thunderstorms in the afternoon, with locally heavy rain and gusty winds being the primary threats. Lingering showers and thunderstorms will continue Saturday night. It will be a warm and humid night with lows in the 70s, though not much below 80 for the urban I-95 corridor from Philadelphia to Wilmington and also into Delmarva. In addition, surface dew points will be in the 70s which will assist in holding temperatures up more and also result in rather muggy conditions. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Hot and humid on Sunday with highs in the upper 80s to low 90s (cooler along the coast and in the higher elevations of the Poconos), but surface dew points will be in the 70s. This should yield heat index values during peak heating Sunday afternoon to near 100 degrees (the highest values look to be from the urban I-95 corridor down into our Delmarva counties). A cold front approaches from the west and with some increasing ascent results in at least some showers and thunderstorms developing once again especially in the afternoon. A slower arrival time of the cold front should result in a longer time for instability to build, and convective initiation could be assisted by a pre-frontal trough. Given enough shear and instability combined with incoming ascent, there is the potential for some thunderstorms to become locally severe with damaging winds. In addition, increasing precipitable water values (potentially nearing 2.5 inches) will support locally torrential rainfall and therefore a localized flooding risk. The showers and thunderstorms taper off Sunday night as the cold front works its way through the region. High pressure then builds in Monday and Tuesday before weakening and shifting offshore into Wednesday. This will deliver a much less humid airmass across the region along with cooler temperatures, although developing warm air advection should start to boost the temperatures Wednesday afternoon back well into the 80s with dew points also climbing back into the 60s. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...Stratocumulus clouds have developed and spread across the area, and MVFR ceilings will likely affect all TAF sites through around 16z, so a TEMPO group has been added for all TAF sites. The cloud bases will lift by midday into the afternoon, but a scattered to broken deck will likely remain through the afternoon. Northwest winds 5 to 10 kt, with occasional gusts 15-20 kt in the afternoon are expected. A sea breeze may develop around 21-23Z and turn winds more southwesterly at KACY and possibly KMIV. High confidence overall, except lower confidence in timing of improving conditions. Tonight...VFR. Winds shifting to be mainly out of the north around 5 knots. High confidence. Outlook... Friday...VFR. Saturday and Sunday...Some afternoon and evening showers and thunderstorms will result in periods of sub-VFR conditions. Monday...VFR. && .MARINE... Sub-SCA conditions are expected through tonight. Southwest winds around 10 knots become northerly tonight and increase to 10-15 knots. A few gusts around 20 knots possible. Seas of 2-4 feet throughout the period. Outlook... Friday...The conditions are anticipated to be below Small Craft Advisory criteria. Saturday and Sunday...Small Craft Advisory conditions probable as southerly flow increases ahead of a cold front. Showers and thunderstorms may produce locally gusty winds. Monday...The conditions are anticipated to be below Small Craft Advisory criteria. Rip Currents... Today...West-northwest winds around 10 mph will become southerly in the afternoon. Breaking waves of 2-3 feet for southeast facing New Jersey beaches and 1-2 feet for the remainder of New Jersey as well as Delaware beaches. Due to higher waves along the southeast facing New Jersey beaches, opted for a MODERATE risk for the development of dangerous rip currents for Ocean, Atlantic, and Cape May. A LOW Risk for the development of dangerous rip currents is forecast for Monmouth County and the Delaware beaches. Friday...Northeast to east-southeast winds 10-20 mph. Breaking waves of 2-3 feet for all beaches. With more of an onshore flow and winds being a bit greater than Thursday, opted to go with a MODERATE risk for the development of dangerous rip currents for the New Jersey and Delaware beaches. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ SYNOPSIS...Gorse/MPS NEAR TERM...AKL/MPS/Robertson SHORT TERM...Gorse/MPS LONG TERM...Gorse/MPS AVIATION...AKL/Gorse/MPS/Robertson MARINE...AKL/Gorse/MPS