243 FXUS61 KPHI 120742 AFDPHIArea Forecast Discussion National Weather Service Mount Holly NJ 342 AM EDT Sun Oct 12 2025
.SYNOPSIS... A coastal storm will affect the region through Monday bringing significant impacts to parts of our area. Improving conditions expected by Tuesday as the storm weakens and moves out to sea. High pressure will begin building back into the region during the middle to end of next week.
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.NEAR TERM /THROUGH MONDAY/... ***SIGNIFICANT IMPACTS FOR OUR COASTAL COUNTIES FROM A COASTAL STORM TODAY THROUGH MONDAY***
As of early this morning, a primary surface low was positioned off the South Carolina coast. A secondary low was starting to develop closer to Cape Hatteras, and this low will be the main impact on our weather thru Monday. This low will strengthen as it heads northward, eventually stalling just off the Jersey Shore before starting to weaken and move away Monday night and beyond. As the pressure gradient tightens on its northwestern flank, a low level easterly jet will intensify, with winds likely gusting up to 60 mph near the immediate coast and 50 mph across interior coastal NJ and DE. Further inland, the jet dwindles markedly, with only gusts of 30-40 mph in Philly and even lower further inland. Strongest winds look to spread north along the coast starting in Delaware late this afternoon and continuing north to near Sandy Hook by late tonight before they begin to dwindle towards dawn Monday. Thus, inherited high wind warnings and wind advisories have been maintained as-is.
Rain-wise, however, the trend continues in the drier direction for most. This low will be relatively compact, and drier air will be trying to drain southwestward on its northwest flank, so heavy rainfall across much of the area now looks like more of a struggle. The entire area will get SOME rain, but it now looks more likely that the majority of our region will receive less than an inch. The exception is along the immediate coastal counties, where 1-3 inches still looks probable, enhanced by the strong low-level jet ejecting onto the coast. For coastal areas, steadiest rain will be later today into tonight, but inland, wraparound moisture as the low begins to weaken means that Monday may be the wettest day overall.
Temperature-wise, most areas should be in the 60s again today, but as cooler air wraps around the system, temps will fall into the 50s tonight and much of the area will not be able to return to the 60s on Monday thanks to clouds and lingering rain.
See the marine and coastal flood sections below for more details on those hazards from this system.
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.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... We continue to deal with our coastal storm Monday night but it does start to weaken and this trend continues into Tuesday. As this low weakens, it also starts to move away from our area. Some model guidance shows the potential still for a secondary low developing to the south of our initial low. The bottom line is that we continue to deal with rain Monday night into Tuesday morning with the higher PoPs closer to the coast with lower PoPs as you head west. By Tuesday afternoon, we are much drier with just a lingering shower possible for the coastal areas.
Winds do stay elevated Monday night and Tuesday as the coastal storm is still near and we continue to have a tight pressure gradient. On Monday night, gusts of 20-30 for inland areas and 30-40 mph still for the coastal zones. For Tuesday, wind gusts are 15-20 mph for most of the inland areas with 20-30 mph gusts near the coast.
Our coastal storm pushes more out to sea by Tuesday night. We are dry Tuesday night with clouds decreasing. Wind gusts remain at around 15-20 mph inland and 20-30 mph near the coast due to the tight pressure gradient remaining.
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.LONG TERM /WEDNESDAY THROUGH SATURDAY/... A broad area of high pressure builds in across the Great Lakes region by midweek and sinks southeast a bit closer to our area by the end of the week. This high pressure system becoming our dominant weather feature leads to minimal cloud cover and a stretch of dry conditions. Wednesday is a bit more mild compared to Thursday and Friday as cold air advection becomes more dominant for the end of the week with below normal temperatures anticipated. Temperatures may begin to moderate on Saturday.
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.AVIATION /07Z SUNDAY THROUGH THURSDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas.
Thru 12Z...MVFR ceilings, however times of VFR ceilings at some terminals. Some spotty showers will result in visibility restrictions at times. Northeast winds 10-15 knots with gusts to 20-25 knots late (highest toward the coast, slower increase at KABE and KRDG). Low confidence regarding ceiling height and visibility timing/details.
Today through Monday...MVFR/IFR conditions with rounds of rain moving through, with the most widespread rain looking to occur mostly tonight into Monday. Northeast winds 15-25 knots with gusts 25-40 knots, highest at KACY and KMIV. Low confidence on timing details, especially with visibility restrictions.
Outlook...
Monday Night...Restrictions expected with showers and low clouds. Wind gusts diminish to around 15-25 kt out of the north/northeast.
Tuesday...Conditons improve but sub-VFR conditions possible with lingering showers and clouds. Wind gusts could get near 20 kt at times.
Wednesday and Thursday..VFR with no significant weather.
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.MARINE... No changes made at this point to the marine hazards. East to northeast winds and waves are increasing early this morning and this will continue through today. The strongest winds are expected during late this afternoon and evening before gradually subsiding overnight. Still expecting storm force winds on the lower Delaware Bay and the NJ/DE Atlantic coastal waters. For the upper Delaware Bay, expect gale conditions.
Dangerous seas up to 20 feet are expected. Periods of rain and sea spray restricting visibility at times, especially this afternoon into Monday.
Outlook...
Monday night through Thursday...Conditions will begin to improve as the storm weakens and begins to move away. However, near gale force winds may linger through Tuesday and seas remain near 10-12 feet. On Wednesday and Thursday, SCA winds and elevated seas above 5 feet look to continue.
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.TIDES/COASTAL FLOODING... Coastal Flood Advisories continue for the tide cycle early this morning before the larger event later today. The latest numbers for the upcoming tide were similar to previous fcst, so saw no need for any major changes. Either low-end minor tidal flooding or just below that is expected early this morning.
Meanwhile, there is an increasing risk of moderate to major coastal flooding impacts beginning today through Monday as a coastal storm impacts the region. Guidance still varies in potential outcomes of this storm with regard to severity of coastal flood impacts locally, however we remain very concerned about the potential for significant impacts from this storm along our coasts. At this time, the greatest threat of impacts are anticipated to occur along the Atlantic coasts of New Jersey and Delaware, and Delaware Bay. A Coastal Flood Warning remains in effect for Sunday through Monday.
Severe beach erosion and dune breaching are quite possible along the entire New Jersey Shore and for Delaware Beaches due to the very high surf conditions that are expected. Interests along the Atlantic coast, Delaware Bay, back bays, and tidal waterways should remain alert for forecast updates regarding this significant coastal flood event.
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.PHI WATCHES/WARNINGS/ADVISORIES... PA...Coastal Flood Advisory from 2 PM this afternoon to 11 PM EDT Monday for PAZ070-071-106. NJ...Coastal Flood Warning from 11 AM this morning to 9 PM EDT Monday for NJZ016. Coastal Flood Advisory until 8 AM EDT this morning for NJZ021>025. Coastal Flood Warning from 8 AM this morning to 8 PM EDT Monday for NJZ012>014-020>027. Wind Advisory from 11 AM this morning to 6 AM EDT Monday for NJZ013-020-022-027. High Wind Warning from 11 AM this morning to 6 AM EDT Monday for NJZ014-023>026. Coastal Flood Advisory from 2 PM this afternoon to 11 PM EDT Monday for NJZ017>019. DE...Coastal Flood Warning from 11 AM this morning to 9 PM EDT Monday for DEZ001. Coastal Flood Advisory until 8 AM EDT this morning for DEZ002>004. Coastal Flood Warning from 8 AM this morning to 8 PM EDT Monday for DEZ002>004. Wind Advisory from 11 AM this morning to 6 AM EDT Monday for DEZ003. High Wind Warning from 11 AM this morning to 6 AM EDT Monday for DEZ004. MD...None. MARINE...Gale Warning until 8 PM EDT Monday for ANZ430. Storm Warning until 8 PM EDT Monday for ANZ431-450>455.
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SYNOPSIS...Guzzo/RCM NEAR TERM...RCM SHORT TERM...Guzzo LONG TERM...Guzzo AVIATION...Guzzo/RCM MARINE...Guzzo/RCM TIDES/COASTAL FLOODING...
NWS PHI Office Area Forecast Discussion