Philadelphia, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

833
FXUS61 KPHI 060636
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
236 AM EDT Sat Sep 6 2025

.SYNOPSIS...
High pressure offshore dominates most of today, then a strong
cold front approaches this afternoon and crosses the region
tonight. This front will become nearly stationary over New
Jersey and Delmarva through Sunday, and weak low pressure may
track on this boundary Sunday afternoon. The front departs
Sunday night as high pressure builds in from the west for the
start of the new week. Low pressure may track along the coast on
Wednesday. A cold front will then cross the region Thursday
into Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Scattered strong to severe thunderstorms are expected this
afternoon and evening, with damaging wind gusts as the primary
threat. Some urban and poor drainage flooding is possible as
well.

A relatively quiet morning is ongoing, and that will generally
remain the case as a cold front currently over western
Pennsylvania is modestly progressing towards our area, and will
be the focus for the development of showers and thunderstorms in
the afternoon and evening. Some patchy fog is possible this
morning as well, though mainly in valleys and more rural and
sheltered regions.

As the front and incoming shortwave aloft get closer this
afternoon, coverage of showers and thunderstorms quickly
increases as we get towards the PM hours. Ahead of the front,
skies will be mostly sunny to partly cloudy, allowing for
destabilization. Temperatures get into mid to upper 80s along
and south/east of the I-95 corridor, with lower temperatures
north and west as the front moving in during the afternoon will
limit heating. With ample instability ahead of the front, and
0-6 km bulk shear around 30-40 kt, sufficient conditions exist
for clusters of storms (and perhaps a few supercells) to quickly
develop in the afternoon. Convection starts to fire around noon
in the Lehigh Valley and Poconos and slowly pushes east,
getting to the I-95 corridor by the mid to late afternoon.
Storms continue to push east and should be at the coast by the
late afternoon/early evening. While the severe threat diminishes
quickly after 8 PM, some backbuilding and anafrontal
precipitation could result in scattered showers and pockets of
heavier rain hanging around through the first half of the night.
Conditions slowly improve as the night goes on and drier air
works in behind the departing front.

Overall, the main threat will be damaging wind gusts through
the afternoon and evening. No real changes to the convective
outlook with a SLIGHT (2/5) Risk in effect for the I-95 area and
surrounding suburbs. Towards the outer western edges of the CWA
in the Poconos and Lehigh Valley, a MARGINAL (1/5) risk is in
place as the front coming in earlier in the day may limit the
severe potential. The front coming in later near the coast and
across southern Delmarva will also reduce some of the risk for
damaging winds, where a MRGL risk is in place.

In addition to the severe threat, there is a threat for some
flash flooding. Main area to watch will be the urban corridor as
rainfall rates over 1" per hour are certainly possible with the
heaviest storms. SLIGHT (2/4) risk is in place for excessive
rainfall for the I-95 corridor, with a MARGINAL (1/4) elsewhere.
Rainfall amounts generally around 0.5-1" with locally higher
amounts likely. Highest chance to see higher amounts will be
from the I-95 corridor on east.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The cold front will be hung up over coastal New Jersey and down
into Delmarva. Some weak low pressure may track along this
front, keeping showers in the forecast, mainly for Delmarva and
New Jersey, into Sunday afternoon, and then showers taper off by
sunset. It will be much cooler on Sunday. Clouds and showers
will keep temperatures in the 60s to around 70 for New Jersey
and Delaware, while highs will get into the low to mid 70s in
southeast Pennsylvania and the eastern shores of Maryland.

Skies clear out Sunday night. Turning much cooler with lows in
the upper 40s in the southern Poconos, Lehigh Valley, and
northern New Jersey, and in the low to mid 50s elsewhere.

Sunny and mild on Monday with highs in the 70s, and then lows
Monday night will be similar to Sunday night.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure builds in from the west, and the center of the
high will pass north of the area Tuesday. Low pressure develops
over the Southeast, and clouds associated with this low will
build to the north. While Tuesday will start out mostly sunny,
skies become partly to mostly cloudy late in the day. Mild with
highs in the low to mid 70s.

Low pressure then tracks along the coast, but mostly offshore.
This looks to bring scattered showers, mainly over Delaware and
New Jersey, Tuesday night through Wednesday night. This will
keep temperatures cooler along the coast as compared to
southeast Pennsylvania, with highs generally in the low to mid
70s.

Weak high pressure builds trough the region Wednesday night
through Thursday morning. Another cold front crosses the region
Thursday night through Friday, but at this time, it looks to be
a dry frontal passage. Turning warmer on Thursday with highs in
the upper 70s to lower 80s, then cooler on Friday with highs in
the low to mid 70s.

Generally followed the NBM during this time.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through 12z...VFR. Southerly winds around 5 kt. Slight chance
of patchy fog (15-20%) but did not include restrictions at any
terminal. Moderate confidence.

Today...VFR bulk of day, but intervals of sub-VFR increasingly
likely later in the day as showers and storms develop, some of
which could produce strong wind gusts. Outside of storms, winds
generally southwesterly around 10 kts, with a few gusts up to 20
kts possible ahead of developing storms. Included VCTS at all
TAF sites for portions of the afternoon and evening. Moderate
confidence.

Tonight...Some shower activity lingers through the first half
of the night resulting in MVFR/IFR restrictions, primarily for
the I-95 and South Jersey terminals. An improvement to VFR is
possible late. Winds become northwesterly right around 00z, and
stay around 5-10 kt through the night. Low confidence.

Outlook...

Sunday...Lingering sub-VFR conditions, mainly at KMIV/KACY, in
stratus/SHRA. Improving conditions otherwise.

Sunday night through Tuesday...VFR. NSW.

Tuesday night through Wednesday...Generally VFR, but sub-VFR
conditions possible at KMIV/KACY in SHRA.

&&

.MARINE...
No marine headlines expected through the morning. Southerly
winds around 10-20 kt with seas 2 to 4 feet.

For this afternoon, a Small Craft Advisory is in effect for
coastal zones north of Cape Henlopen as southerly winds increase
to 20 to 25 kt. Lower winds expected south of Cape Henlopen and
within Delaware Bay as gusts remain around 20 kt. Thunderstorms
possible on the Delaware Bay after 18z and the ocean after 21z
may result in some Special Marine Warnings being issued.

For tonight, winds diminish as a cold front comes through,
bringing winds out of the northwest around 10-20 kt. Seas 2 to 4
feet. Scattered showers and thunderstorms expected on the water
through most of the night.

Outlook...

Sunday through Monday night...Sub-SCA conditions. N winds
generally 10 to 15 kt, turning E Monday night.

Tuesday through Wednesday...SCA conditions possible. E winds 15
to 20 kt with gusts up to 25 kt. Seas 3 to 5 feet.

Rip Currents...

Saturday...Southerly onshore/shore parallel winds on Saturday
will be 15-20 mph by the afternoon. Wave period is 6-7 seconds
but could be down to 4-5 seconds by the late afternoon as wind
driven waves become more dominant. Breaking wave heights of 2-3
feet are forecast for the beaches of New Jersey. As a result, a
MODERATE risk for the development of rip currents is forecast
for all NJ beaches. For the Delaware Beaches, winds will be more
shore parallel/slightly offshore. Breaking waves of 1-2 feet
are forecast and as a result a LOW risk for the development of
rip currents is forecast for the Delaware Beaches.

Sunday...Winds turn offshore on Sunday which should decrease the risk
for the development of rip currents. Breaking waves look to be
around 1-2 feet with a 6-8 second period. Therefore, a LOW risk
for the development of rip currents is forecast for all beaches
on Sunday.

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

&&

.TIDES/COASTAL FLOODING...
Some spotty minor tidal flooding was observed with the high tide
last night and more of the same is expected tonight and perhaps
Saturday Night within the upper Delaware Bay, tidal Delaware
River, and northeastern shore of Chesapeake Bay. Not expecting
the need for Coastal Flood Advisories at this point, but some
standing water may be seen in low lying areas within these
communities near tidal areas.

No tidal flooding is expected along the Atlantic Ocean front.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory from noon today to 6 PM EDT this evening
     for ANZ450>454.

&&

$$

SYNOPSIS...MPS
NEAR TERM...Hoeflich
SHORT TERM...MPS
LONG TERM...MPS
AVIATION...Hoeflich/MPS
MARINE...Hoeflich/MPS
TIDES/COASTAL FLOODING...