297
FXUS61 KPHI 121054
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
654 AM EDT Fri Sep 12 2025

.SYNOPSIS...
High pressure will continue to extend into our area from the
northeast today, then it shifts eastward and gradually weakens over
the weekend. A cold front crosses our area later Sunday into Monday,
then high pressure builds to our north Tuesday through Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure continues to drift eastward across the northeastern
United States through the day today before becoming centered
offshore tonight. As a result, the weather in our region will
continue to remain tranquil and dry through the period.

Temperatures today will rise into the upper 70s to low 80s this
afternoon (mid 70s along the coast and in the Poconos). Light
winds out of the northeast around 5-10 mph. A very pleasant day
overall.

Tonight, with the center of the high offshore, winds look to become
more easterly, though remaining light. As a result, a little bit of
marine moistened air may filter in, particularly in Delmarva and the
New Jersey coastal plain and some scattered low stratus may develop.
Lows tonight look to fall into the 50s once again, with temperatures
in the Philly metro and along the coast staying closer to 60.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Mild and mainly dry conditions continue.

An upper-level trough across eastern Canada is forecast to amplify
southeastward and move across the Northeast and northern Mid-
Atlantic later Saturday through Sunday. Weakening high pressure
initially extending into our area from the northeast shifts eastward
Saturday. This will result in the low-level flow veering more from
the southeast or south. There could be some spots of fog to start
early Saturday, otherwise some clouds around especially inland from
the coast. A mild afternoon with high temperatures in the low 80s
for many areas, although cooler along the coast with a sea breeze.

As the upper-level trough axis arrives during Sunday, some
potentially stronger shortwave energy rounding its base may be
enough along with an incoming cold front to produce a few showers.
Given the sharpness of the trough in some of the guidance, cannot
rule out isolated thunder, however deeper moisture looks to be
lacking plus the main forcing for ascent looks to cross New England.
This leaves our area with minimal chances for any showers. Given not
much of a chance, kept it dry which is what the NBM output currently
has for our area Sunday and Sunday night. The warmth looks to peak
Sunday with high temperatures in the low to mid 80s for most,
although still cooler along the coast given an onshore wind
component.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Summary...Temperatures near average overall with little in the way
of any rain chances.

Synoptic Overview...An upper-level trough shifts off the New England
coast with its axis extending southwestward into the Southeast U.S.
Some energy lingering behind looks to develop into a closed low
across the Southeast U.S. Monday and Tuesday. As this occurs, a
ridge builds across the Ohio Valley, Great Lakes and into adjacent
Canada. The model guidance consensus is for a weaker closed low
across the Southeast U.S. coast instead of a potent closed low
dropping into the Mid-Atlantic from the north. Some guidance however
does not close off the trough. The closed low should weaken through
Thursday as it drifts westward, while a ridge is over our area. May
need to watch another upper-level trough across eastern Canada
Thursday to see if that ends up amplifying more southward. At the
surface, high pressure builds into New England but extends into our
area and this pushes a weak front well to our south early Monday. A
front off the coast of the Carolinas may support low pressure to the
east of the closed low. There are hints in some of the guidance of a
surface trough extending northward from this low into the Mid-
Atlantic Tuesday through Thursday. High pressure however remains
anchored over the Northeast overall through Thursday.

For Monday and Tuesday...The model consenus is for a separation of
upper-level troughs. The main one exits New England Monday, however
trailing energy within the southwest part of the trough may result
in a closed low developing in the Southeast U.S. Some guidance
however does not show a closed low. A front off the Southeast U.S.
coast on the east side of the potentially developing closed low
looks to support low pressure. However, a building ridge northward
across the Ohio Valley, Great Lakes and toward New England will
support surface high pressure. This surface high extends southward
into the Mid-Atlantic and results in a continuation of dry
conditions. There are some hints that an inverted trough develops
from the surface low off the coast of the Carolinas and extends
northward toward the Mid-Atlantic. The positioning of the surface
high will result in a low-level onshore flow pattern which will keep
our area more stable along with some cooler temperatures closer to
the coast.

For Wednesday and Thursday...A potentially closed low should
gradually weaken as it shifts westward across the Gulf coast states.
As this occurs and energy moves across the northern Plains and
Midwest, the ridge is forecast to weaken some and therefore the
surface high across our region should also weaken. There continues
to be the potential for a weak inverted trough extending northward
toward the Mid-Atlantic, however it is not all that clear whether
this results in any shower development. Overall we look to be in a
more stable environment with little to no shower chances. No
significant changes were made from the NBM output.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR. Light winds from the northeast around 5 knots or
less. High confidence.

Tonight...Mainly VFR. Light winds less than 5 knots, favoring an
easterly direction. Scattered low stratus may develop as a result
but confidence is low in there being restrictions. Moderate
confidence in the overall pattern.

Outlook...

Saturday...Locally sub-VFR conditions possible early due to some
low clouds/fog, otherwise VFR.

Sunday through Tuesday...VFR with no significant weather.

&&

.MARINE...
Conditions will remain below Small Craft Advisory criteria through
tonight. Winds around 10 knots, mainly out of the east to northeast,
along with seas of 2 to 3 feet, are expected.

Outlook...

Saturday through Monday...The conditions are anticipated to be below
Small Craft Advisory criteria.

Tuesday...Small Craft Advisory conditions may develop on the ocean
zones due to seas building to around 5 feet.

Rip Currents...

For today, northeast to east winds around 10 mph. Breaking waves in
the surf zone of 2-3 feet with an easterly swell around 7 seconds
are forecast. As a result, there is a MODERATE risk for development
of dangerous rip currents at all beaches.

For Saturday, east to southeast winds increasing to 10-15 mph.
Breaking waves in the surf zone of 2-3 feet with an easterly swell
around 8 seconds are forecast. As a result, there is a MODERATE risk
for development of dangerous rip currents at all beaches.

For specific beach forecasts, visit weather.gov/beach/phi

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.

&&

$$

SYNOPSIS...Gorse
NEAR TERM...AKL
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...AKL/Gorse
MARINE...AKL/Gorse