304 FXUS61 KPHI 102334 AFDPHIArea Forecast Discussion National Weather Service Mount Holly NJ 734 PM EDT Wed Sep 10 2025
.SYNOPSIS... High pressure centered from New England to Nova Scotia Canada will continue to shift eastward today. An area low pressure off the coast of the Carolinas tracks north and northeastward through today, then moves even farther away from our area during Thursday. A cold front arrives Sunday night into Monday, then high pressure builds to our north Tuesday.
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.NEAR TERM /THROUGH THURSDAY/... Evening Update: Clouds have continued to scatter out slightly sooner than initially forecast along with the showers so the new forecast reflects the updated timing.
A low pressure system off the coast east of Virginia will continue to bring mainly cloudy skies with some spotty showers around through this afternoon. The best chances for these showers will continue be near and south/east of the urban corridor and any precip should also continue be quite light. It will also remain breezy with NE winds gusting to around 20-25 mph at times.
As we head into this evening, the low will be starting to pull away so any showers will be ending. Some slow clearing will start to then occur by the overnight period from north to south as high pressure builds in from the north. Lows should be generally in the 50s to low 60s.
For Thursday, high pressure will bring mainly sunny skies with seasonable temperatures along with light northerly winds. Expect highs generally in the upper 70s to around 80 with comfortable humidity levels.
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.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... An upper-level trough axis is forecast to be arriving during the short term forecast period. In terms of any shortwave activity, the main piece of energy looks to rotate through on Saturday but surface high pressure will be centered to the north with it extended down into our area through the short term period. This will keep us dry through Saturday.
For Thursday night, we are dry with not much in the form of cloud cover. Overnight lows are in the 50s. Friday looks mostly to partly sunny with temperatures in the mid 70s to low 80s. By the start of the weekend, we are still mostly to partly sunny on Saturday with highs in the mid 70s to near 80.
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.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... During the long term period, an upper-level trough across much of eastern Canada is forecast to amplify across the Northeast and the Mid-Atlantic Saturday into Sunday. The latest model guidance has trended with this becoming closed off to our north on Sunday and sinking southward into the Mid-Atlantic as a closed low on Monday. This closed low may meander into Tuesday. The latest Euro/Canadian models favor the closed low scenario while the GFS does show the trough closing off to the north but the closed low stays to the north and eventually east. In general, the forecast has trended with more in the form of shower and thunderstorm chances for this period compared to previous forecasts. There is still uncertainty with this forecast as it is in the long term period and PoPs were kept at slight chance to chance given the uncertainty.
For Sunday, we trend partly cloudy with a slight chance to chance (15-30%) for some showers and thunderstorms for our north and west zones by the afternoon and evening. Overnight Sunday, we become partly to mostly cloudy with the potential for showers and thunderstorms (15-30%) across much of the area. At the surface, a cold front will be sinking southeast and we have that signal for the closed low in the upper levels. All of this is helping lead to some showers and thunderstorms. The signal from some guidance still has the closed low in the upper-levels which results in a slight chance to chance (15-30%) of showers and thunderstorms on Monday across much of the area. By Monday night into Tuesday, the closed low starts to depart and upper- level ridging builds in from the southwest with a high pressure system at the surface also moving in which leads to drier conditions for Tuesday. In terms of temperatures during the long term period, highs will mainly be in the 70s with overnight lows in the 50s.
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.AVIATION /00Z THURSDAY THROUGH MONDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.
Tonight...Lingering sub-VFR conditions diminish between 01-03z. I-95 terminals should return to VFR by late evening, but MVFR cigs will linger longer at KMIV/KACY. Light northerly winds around 5 knots or less, except at KMIV/KACY where wind speeds around 5-10 knots are expected. Moderate confidence.
Thursday...VFR with mainly clear skies and northerly winds around 5 knots. High confidence.
Outlook...
Friday through Sunday...VFR with no significant weather.
Monday...Sub-VFR possible with any showers or thunderstorms.
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.MARINE... Small Craft Advisory remain in effect for the Atlantic Ocean zones into Thursday morning due to elevated seas of 5-7 feet and northeast winds gusting up to 25-30 knots. Scattered showers possible for all marine waters through this evening. Northeast winds turn northerly tonight and begin to decrease but seas will continue to remain elevated.
The Small Craft Advisory ends at 11 AM Thursday as beyond this time sub SCA conditions are expected.
Outlook...
Friday through Monday...Conditions are anticipated to be below Small Craft Advisory criteria.
Rip Currents...
A HIGH RISK OF RIP CURRENTS CONTINUES THROUGH THURSDAY EVENING.
For Thursday, north to east winds around 10 mph with gusts around 15 mph. Breaking waves in the surf zone of mainly 3-5 feet are forecast. An easterly swell around 7 seconds will persist as the rough surf conditions slowly improve. Due to these conditions, a HIGH risk for development of dangerous rip currents at all beaches is expected as lingering rough surf conditions remain.
For Friday, north to east winds around 10 mph with gusts around 15 mph. Breaking waves in the surf zone of mainly 1-3 feet are forecast. An easterly swell around 7 seconds will persist as the rough surf conditions gradually improve. As a result, MODERATE risk for development of dangerous rip currents at all beaches is expected.
For specific beach forecasts, visit weather.gov/beach/phi
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.TIDES/COASTAL FLOODING... Strong northeasterly flow continues today, before weakening tonight into Thursday. Despite being three days removed from the Full Moon, astronomical high tides are still high enough with water pushing into the coast for minor tidal flooding to occur at most of our tide gauge sites.
The more widespread minor tidal flooding looks to occur with the high tide cycle today. Therefore, a Coastal Flood Advisory remains in effect for all coastal zones along the ocean, backbays and as well as the Delaware Bay through this afternoon. Additional minor tidal flooding may occur with future high tide cycles on Thursday and into Friday as well.
For the tidal Delaware River, some minor tidal flooding is forecast with today`s high tide cycles and even on Thursday into Friday. Much of this may be below minor advisory level and given lower confidence will continue to hold off on a Coastal Flood Advisory for now.
No tidal flooding is expected along the northeast coast of Chesapeake Bay.
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.PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...Coastal Flood Advisory until 5 PM EDT Thursday for NJZ016. Coastal Flood Advisory until 4 PM EDT Thursday for NJZ012>014- 020>027. High Risk for Rip Currents through Thursday evening for NJZ014- 024>026. DE...Coastal Flood Advisory until 5 PM EDT Thursday for DEZ001. Coastal Flood Advisory until 4 PM EDT Thursday for DEZ002>004. High Risk for Rip Currents through Thursday evening for DEZ004. MD...None. MARINE...Small Craft Advisory until 11 AM EDT Thursday for ANZ450>455.
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SYNOPSIS...Gorse/Guzzo NEAR TERM...Deal/Fitzsimmons SHORT TERM...Guzzo LONG TERM...Guzzo AVIATION...Deal/Fitzsimmons/Guzzo MARINE...DeSilva/Fitzsimmons/Guzzo TIDES/COASTAL FLOODING...
NWS PHI Office Area Forecast Discussion