639 FXUS61 KPHI 241058 AFDPHIArea Forecast Discussion National Weather Service Mount Holly NJ 658 AM EDT Wed Sep 24 2025
.SYNOPSIS... A cold front will gradually track into the region Wednesday into Wednesday night before stalling. The front may lift back north as a warm front on Thursday night before another cold front passes through late Friday and Friday night. Broad high pressure will then approach from the west on Sunday into early next week.
&&
.NEAR TERM /THROUGH TONIGHT/... Observations continue to indicate that fog and low stratus is continuing across the area, with the densest patches mainly where it rained. A Dense Fog Advisory has been issued for southeastern Pennsylvania as a result. Take extra care while driving this morning.
Heading into the daytime hours, a slow-moving cold front will slowly drag into the region before stalling across the central part of the area. As a result, some scattered showers and storms may developing beginning late this afternoon, most likely for areas north of I-195 and the Pennsylvania Turnpike. Otherwise, high temperatures this afternoon will be mainly in the upper 70s to low 80s.
More focused development of showers and thunderstorms is expected across the northern two- thirds of the region by late this evening and continuing into the overnight hours. PoPs have increased to around 60-80% with chances remaining around 40-50% for the most southern areas. Areas north of I-195 and the Pennsylvania Turnpike generally look to receive between 0.5 and 1.5 inches of rain through tonight, with localized areas of up to 2-3 inches possible. Otherwise, overnight lows tonight will dip into the 60s once again.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... The stationary boundary lifts back north as a warm front Thursday morning ahead of the main surface low and associated cold front. As a result, we will see our greatest chance (50-80%) for showers and thunderstorms across the region on Thursday. Afternoon temperatures will be more moderate thanks to more widespread rainfall with highs only reaching the mid 70s to around 80 for much of the region. Areas across the southern Delmarva that may not see the rain until later in the afternoon and evening could warm into the mid 80s. Dew points will remain elevated, making it an overall warm, muggy, and rainy day. Combined precipitation totals Wednesday and Thursday will be around 1 to 2 inches with locally higher amounts possible. The Storm Prediction Center has also placed the region in a Marginal risk for severe weather. Depending on how the system evolves through the day, we could see MUCAPE values increase to around 1000-1500 J/kg with 0- 6km bulk shear increasing to 40 kts or more by the afternoon. That said, if substantial cloud coverage lingers, the region will lack sufficient destabilization across the region and greatly limit the development of strong to severe thunderstorms Thursday afternoon and evening.
The cold front will gradually continue pushing offshore Friday and into Friday night. Can`t fully rule out some lingering showers during the day as a result, but overall it will be a drier day with high pressure slowly building in from the west. Afternoon highs remain in the upper 70s to low 80s with lows in the mid 50s to mid 60s.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/... A weak surface low will develop along the stalled boundary just south and east off the Mid Atlantic Coast. As a result, a few showers may linger Saturday and Sunday with the greatest chances across southern NJ and the Delmarva. Temperatures will be at or above normal through the weekend.
What happens beyond Sunday and into early next week is yet to be seen and highly uncertain. Broad high pressure will develop over the center of the country, gradually building east with time. Eyes will also be on the tropics as most global forecast guidance has been consistent on developing a tropical cyclone somewhere over the western Atlantic early next week with a cut-off upper level low over the Deep South. How all these features interact with one another will ultimately determine what kind of weather we encounter beyond Sunday. More to come on this in the coming days.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas...
Today...Sub-VFR conditions in the morning with lingering fog/stratus, dissipating around 13-14Z. VFR conditions are expected there after. Southerly winds around 5 knots or less. Moderate confidence.
Tonight...Sub-VFR conditions expected with showers likely (60-80% chance) and a few thunderstorms possible (30-40% chance). Southeast winds around 5 knots or less. Moderate confidence.
Outlook...
Thursday through Thursday night...Sub-VFR conditions are expected at times. Showers are likely with a chance of thunderstorms, primarily in the afternoon and evening hours. Patchy fog is also possible.
Friday through Sunday...Sub-VFR conditions likely, especially early Friday, before improving by the weekend. A chance of showers will continue through Sunday.
&&
.MARINE... Sub-SCA conditions are expected through tonight. Southerly winds around 10-15 knots, with some gusts up to 20 knots at times. Showers with a few thunderstorms likely (50-60% chance), from late this evening into early Thursday Seas of 2-4 feet throughout.
Outlook...
Thursday through Sunday...No marine headlines expected attm, although we`ll keep an eye on Thursday night ahead of the cold front. Showers with a chance of thunderstorms possible each day.
Rip Currents...
For Wednesday...a HIGH risk of rip currents is in place at all beaches as a long period 12 second onshore swell from distant Hurricane Gabrielle remains. Breaking waves of 2 to 4 feet with shore parallel winds around 10-15 MPH or so. Rip Current Statement was extended through Wednesday evening.
For Thursday...elected for a HIGH risk at all Jersey Shore locations and MODERATE for Delaware. The onshore swell decreases to around 10 seconds, with lower breaking waves around 2 to 3 feet. Winds will be around 10-20 MPH, mainly offshore for DE and either shore parallel or slightly onshore in NJ depending on your location. This could change and become a MODERATE at all shore points, but confidence was not quite there to drop the HIGH yet for the Jersey Shore.
For specific beach forecasts, visit weather.gov/beach/phi
&&
.PHI WATCHES/WARNINGS/ADVISORIES... PA...Dense Fog Advisory until 9 AM EDT this morning for PAZ060>062- 070-071-101>106. NJ...High Risk for Rip Currents through this evening for NJZ014-024>026. DE...High Risk for Rip Currents through this evening for DEZ004. MD...None. MARINE...None.
&&
$$
SYNOPSIS...MJL NEAR TERM...AKL SHORT TERM...MJL LONG TERM...MJL AVIATION...AKL/MJL MARINE...AKL/MJL
NWS PHI Office Area Forecast Discussion