512
FXUS61 KPHI 082250
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
650 PM EDT Wed Oct 8 2025

.SYNOPSIS...
High pressure will continue to build southeastward into the region
through Thursday, before it begins to slide eastward and weaken
Friday into Saturday. A coastal low could bring potentially
significant impacts to the region late this weekend into early next
week.

&&

.NEAR TERM /THROUGH THURSDAY/...
The initial cold front that moved through this morning is now
offshore with clearing skies in its wake. Gusty northwest winds
around 25 to 30 mph will continue this afternoon.

Tonight, a secondary cold front will push through the region,
helping shift winds more northerly and allowing skies to become
mostly clear with high pressure building in from the north and west.
Lows tonight will cool off into the low to upper 40s with some upper
30s for our higher elevations and low 50s for the coast. Northerly
winds will persist overnight around 10 mph. While temperatures in
some places may support frost formation, the persistent winds should
remain elevated enough to prevent widespread frost development.

High pressure continues to build in for Thursday bringing sunny
skies and cool temperatures. Afternoon highs will be in the low 60s
with higher elevations in the mid to upper 50s. North to north-
northeast winds will be around 10-15 mph through the day.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
Modest northwesterly flow aloft from the trough departing to the
east will wane through Thursday night as subtle mid-level ridging
builds in. Strong high pressure at the surface will be centered over
northern portions of the Mid Atlantic into New England.

With the cool post-frontal airmass firmly in place, mostly clear
skies, and light winds, temperatures should be able to fall
substantially Thursday night. Lows near freezing are likely for the
Poconos and into far northern NJ. Across most of eastern PA and the
remainder of NJ outside of the urban corridor and coastal regions,
temperatures will likely range from the mid 30s to near 40. For the
urban corridor, coastal locations, and the Delmarva, temperatures in
the mid-upper 40s are expected. Widespread frost is expected in the
Poconos and far northern NJ, with areas of frost possible across
most of eastern PA and the remainder of northern NJ. For this
forecast cycle, have elected not to make any changes to the current
Freeze Watch until the extent of expected freezing temperatures
becomes a bit more clear. Due to similar uncertainties regarding the
areal coverage of frost, will hold off on Frost Advisory issuance
for now as well.

The subtle ridge axis will shift east across the area on Friday,
with the surface high starting to weaken slightly. With that said,
despite perhaps having some increase in clouds, it should remain dry
with afternoon highs generally in the mid 60s. Clouds will continue
to increase from south to north Friday night, with many locations
becoming mostly cloudy by sunrise Saturday. It should remain dry
though, with lows ranging from near 40 in northern areas of eastern
PA and NJ to near 50 near the NJ coast and in the Delmarva.

Saturday should be mostly cloudy to overcast areawide. Most
locations will remain dry, though it is possible that showers could
begin nudging into the Delmarva and far southern NJ near sunset.
Breezy conditions could also begin across the same areas. Afternoon
highs will be in the mid-upper 60s for most.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A potentially significant coastal storm looks to be on the horizon
Sunday through Monday.  However, the forecast remains uncertain and
significant changes could come as we get closer. Main impacts will
be tidal flooding, strong marine winds (and potentially on land if
the system tracks closer), and heavy rain.

Things start to go downhill on Saturday Night as a coastal low
approaches from the south. Rain is expected to overspread the
region, with the heaviest near the coastline, while areas in the
Lehigh Valley/Poconos/northern NJ likely stay dry through the
night. Winds begin to increase, especially over the water and
along the immediate coastline with gusts getting near 40 MPH by
daybreak.

Sunday through Monday will be when our area likely experiences the
brunt of the impacts from the coastal storm. If the current track
holds and the coastal storm does end up just offshore, strong winds
are expected, upwards of 45-55 MPH+ on the coast Sunday afternoon
and Sunday Night, with the potential for these strong winds to
continue well into Monday. Gusts upward of 30-40 MPH will extend
several miles inland to about the I-95 corridor. In addition to the
wind, heavy rain is expected, and a SLIGHT (2/4) Risk Excessive
Rainfall Outlook is in place for the I-95 corridor and points south
and east. We are not fully in the QPF period yet, but some of the
WPC longer-range rainfall products suggest 2-4+ inches of rain
within the SLGT risk, with locally higher amounts certainly
possible. NBM Probability of 2+ inches of rain for New Jersey and
Delmarva was about 30-40%, which is actually quite high being 5-6
days out. Strong northeast winds will also result in water piling up
along the coast, with moderate to even major tidal flooding Sunday
and Monday (more on that below in the Tides/Coastal Flood section).

With all that being said, there remains a lot of uncertainty in the
track of the coastal low, even being within 5 days of the event. The
setup is overall very complex. The surface low will be developing
over the Gulf Stream along a stalled boundary, and its northward
movement will depend on how it interacts with a surface high over
Nova Scotia, an upper level low over the Great Lakes, and even
distant Tropical Storm Jerry. A closer and slower track would bring
more significant impacts while a track further away still will
likely bring hazards, though not as severe. Stay tuned to the latest
briefing packages and forecast updates as things will likely change.

Things look to quiet down on Tuesday and Wednesday as the system
pulls away with rather benign weather and seasonable temperatures
for mid-October.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...VFR. North winds around 5-10 kt. High confidence.

Thursday...VFR. North to NNE winds around 10 kts. High
confidence.

Outlook...

Thursday night through Friday night...VFR. No significant weather.

Saturday...Sub-VFR conditions are possible in low clouds.

Saturday Night...Sub-VFR conditions expected with rain and low
clouds moving in. Gusts out of the NE around 15-25 kt, with
higher gusts upwards of 30 kt possible at KACY.

Sunday through Monday...Sub-VFR conditions expected with rain
and low clouds over the area due to a coastal storm. NE winds
20-30 kt at all terminals except KACY/KMIV, where gusts in the
30-40+ kt range are expected.

&&

.MARINE...
Small Craft Advisory in effect through Thursday. SCA for the
Delaware Bay will remain in effect through Thursday morning with the
ocean zones remaining through the afternoon and into the evening
hours. NNW winds gusting to 25 kts tonight will gradually shift NNE
Thursday morning before diminishing below criteria in the afternoon.
Seas will remain elevated, however, building to 4-6 feet through the
afternoon.

Outlook...

Thursday night...Winds and seas should diminish with time, though
lingering SCA conditions are expected into the overnight hours.

Friday through Friday night...No marine headlines are expected with
winds remaining below 25 kt and seas below 5 feet.

Saturday...Winds and seas will begin to increase late, especially
across southern ocean zones. Marine headlines may become necessary
as early as Saturday afternoon.

Saturday Night through Monday...Hazardous marine conditions are
expected on the waters as a coastal storm moves over the
offshore waters. Storm-force winds upward of 55 kt possible
Sunday afternoon through Sunday Night. Seas 12 to 18 feet.
Marine headlines likely to come in subsequent forecast updates.

&&

.TIDES/COASTAL FLOODING...
A combination of high astronomical tides (King Tides) and modest
northeast winds is expected to result in areas of minor coastal
flooding with the Thursday morning high tide, and potentially the
Friday and Saturday morning high tides as well.

Coastal Flood Advisories have been issued to highlight this threat
for the Thursday morning high tide along portions of the Atlantic
coast and Delaware Bay. Minor coastal flooding may linger on the
back bays after the time of high tide, especially in Sussex (DE) and
Ocean Counties. The Coastal Flood Advisory was extended through
Friday afternoon for Atlantic/Cape May/Cumberland County in New
Jersey, and Kent/Sussex County in DE. The rest of the advisories
could be extended to cover additional high tide cycles if
confidence increases in additional high tides causing minor
coastal flooding.

There is a risk of moderate to potentially major coastal flooding
impacts beginning Sunday and into early next week as a strong
coastal storm impacts the region. Guidance varies in potential
outcomes of this storm with regard to impacts locally, however we
are growing increasingly concerned about the potentially significant
impacts from this storm along our coasts. At this time, the greatest
threat of impacts could be along the Atlantic coasts of southern New
Jersey and Delaware, and Delaware Bay. People with interests in
these areas should remain alert for future updates regarding this
storm.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Freeze Watch from Thursday evening through Friday morning for
     PAZ054-055-061-062.
NJ...Coastal Flood Advisory from 8 AM Thursday to 3 PM EDT Friday
     for NJZ021>025.
     Freeze Watch from Thursday evening through Friday morning for
     NJZ001-007.
     Coastal Flood Advisory from 8 AM to 3 PM EDT Thursday for
     NJZ013-014-020-026-027.
DE...Coastal Flood Advisory from 8 AM Thursday to 3 PM EDT Friday
     for DEZ002>004.
MD...None.
MARINE...Small Craft Advisory until 8 AM EDT Thursday for ANZ430-431.
     Small Craft Advisory until 2 PM EDT Thursday for ANZ450.
     Small Craft Advisory until midnight EDT Thursday night for
     ANZ451>453.
     Small Craft Advisory until 6 AM EDT Friday for ANZ454-455.

&&

$$

SYNOPSIS...Cooper/Staarmann
NEAR TERM...MJL
SHORT TERM...Cooper
LONG TERM...Hoeflich
AVIATION...Cooper/Hoeflich/MJL/RCM
MARINE...Cooper/Hoeflich/MJL
TIDES/COASTAL FLOODING...