312
FXUS61 KPHI 301817
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
217 PM EDT Tue Sep 30 2025

.SYNOPSIS...
A cold front will move through the region tonight, with strong
high pressure building south into the region and remaining in
place through the weekend and into early next week. Several
tropical systems over the western Atlantic ocean will remain
away from the Mid- Atlantic coast.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Our area is currently under fairly weak flow aloft, with
Hurricanes Humberto and Imelda over the Western Atlantic basin
to our southeast, a ridge axis across central portions of the
country, and the polar jet dipping southward into far northern
New England. With time, the ridge over the central tier of the
US will expand eastward into the area, becoming the dominant
feature. At the surface, a cold front to the north of the area
will move through the region tonight. Strong high pressure
centered over portions of Ontario will expand southward into the
area thereafter.

Widespread cloudiness from Imelda`s cirrus shield is prevalent
across the area, though there has been some thinning noted on
visible imagery. With very limited moisture, the approaching
cold front is not expected to trigger any showers. However, it
will bring clearing skies and notably cooler temperatures with
its passage. Lows tonight will generally range from near 50
across eastern PA and northern NJ to the upper 50s to near 60
across southern NJ and the Delmarva. Across the higher
elevations of the Poconos and far northern NJ, temperatures
should fall into the 40s. High temperatures on Wednesday will be
in the upper 60s to near 70 areawide, with mostly clear skies.

With high pressure building to the north and the hurricanes to
our southeast, a tight pressure gradient will begin to take
shape across the area tonight and during the day on Wednesday.
It will be somewhat breezy across the entire area, with gusts to
around 25 mph possible beginning late tonight. Near the coast,
however, this pattern will favor wind gusts perhaps to near 40
mph. Winds should begin to taper off some by late afternoon or
early evening.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Surface high pressure centered over southern Quebec on
Wednesday night will build south over New England on Thursday,
then towards New York City Thursday night and finally end up
over the Atlantic east of New Jersey on Friday. Aloft, an upper
level ridge centered over Indiana Wednesday night will shift
southeastward towards Cincinatti Thursday, towards West Virginia
Thursday night, and into Virginia Friday, weakening gradually as
it does so. There will be a couple of very weak impulses passing
over the ridge and into our region Thursday into Friday,
bringing some high clouds, but that`s all. Otherwise, the cooler
Canadian surface high will promote dry weather with partly to
mostly clear skies and temps just a bit below normal.
Radiational cooling versus advection will determine what the
coolest night is at various locales, with sites that get coldest
with advection (urban areas) more likely to be coolest Wednesday
night when we still have a breeze, but areas which chill best
with radiational cooling (rural locales) likely to be coldest
Thursday night. Patchy frost may occur in the coldest spots of
our northwestern zones (Poconos/NW NJ), but otherwise, nothing
to write home about as it will only be slightly cooler than our
coldest night so far this side of the summer solstice, which was
nearly a month ago. Highs will be on the cooler side, with 60s
in most areas Thursday and creeping up a few degrees closer to
70 on Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Surface high pressure likely settles just southeast of our
region for Saturday, lingering Sunday and Monday before starting
to be pushed eastward Tuesday as surface fronts start to
approach from the west. Aloft, upper ridge will remain in
overall control Saturday, actually strengthen somewhat Sunday as
it relocates to near Cape Hatteras, then starts to weaken a bit
Monday and losing more strength to oncoming shortwaves to the
northwest on Tuesday.

Sensible weather-wise, this means mostly continued dry, with the
chance of rain only starting to creep back up from zero on
Tuesday. It also means partly to mostly clear skies with
gradually warming temps as the air mass continues moderating.
Highs rise slowly towards 80 through Monday, then level off due
to increasing clouds Tuesday, while lows will slowly return to
the 50s for most, with 60s in the warmer spots by Monday night.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas...

Through 00Z...VFR. Broken high clouds. Northeast wind around 10
kt. High confidence.

Tonight...VFR. Broken high clouds will scatter out from north
to south through 01-03Z. Northeast wind generally 10-15 kt.
Gusts 20-25 kt are possible at KMIV and KACY. High confidence.

Wednesday...VFR. Northeast wind 10-15 kt with gusts around 20
kt for most terminals. For KMIV and KACY, northeast wind 15-20
kt with gusts 25-30 kt. Moderate confidence.

Outlook...

Wednesday night through Sunday...VFR with no significant
weather.

&&

.MARINE...
Confidence remains high in gale force winds in frequent gusts
beginning this evening and continuing into Wednesday afternoon.
Based on guidance this afternoon, have upgraded the marine zone
north of Manasquan Inlet to a Gale Warning, and therefore all
ocean zones now have a Gale warning from 6 PM today through 6 PM
Wednesday. Gusts near 40 kt are expected. For the Delaware Bay,
gusts near 30 kt are anticipated a small craft advisory in
place.

Seas across the ocean zones around 4-6 feet initially will grow
to 7- 11 feet during the day Wednesday.

Outlook...
Gales dwindle early Wednesday night, but SCA winds linger into
Thursday. For the ocean waters, SCA wave heights likely continue
through Friday. Sub-SCA conditions likely over the weekend.

Rip Currents...

A high risk of rip currents is likely to continue through the
remainder of the week. However, the surf program ends today. No
further surf forecasts or rip current statements will be issued
until May 2026.

&&

.TIDES/COASTAL FLOODING...
Strengthening northeast winds through later today into
Wednesday will lead to a piling up of water along the ocean
front, back bays, and the Delaware Bay. Widespread minor coastal
flooding will develop for these areas with the Wednesday
afternoon and evening high tide cycle. Tidal flooding is not
expected along the Chesapeake Bay for the eastern MD zones.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...High Risk for Rip Currents until 7 PM EDT this evening for NJZ014-
     024>026.
DE...High Risk for Rip Currents until 7 PM EDT this evening for DEZ004.
MD...None.
MARINE...Small Craft Advisory from 11 PM this evening to 6 PM EDT
     Wednesday for ANZ430.
     Small Craft Advisory from 6 PM this evening to 6 PM EDT
     Thursday for ANZ431.
     Small Craft Advisory until 6 PM EDT this evening for
     ANZ450>455.
     Gale Warning from 6 PM this evening to 6 PM EDT Wednesday for
     ANZ450>455.

&&

$$

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