Ridley, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

082
FXUS61 KPHI 060100
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
900 PM EDT Fri Sep 5 2025

.SYNOPSIS...
Weak high pressure dominates tonight. A strong cold front arrives
Saturday afternoon/evening before moving offshore early Sunday.
Expansive Canadian high pressure will build in its wake through
the middle of the week. Another cold front is then expected to
cross through late Thursday into Friday.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
Current pattern shows Bermuda high pressure remaining off to our
southeast, with broad southwesterly flow across the region both
at the surface and aloft. A strong surface and upper level low
pressure is located over Ontario, with a cold front extending
south and then west from that through the eastern Great Lakes,
Ohio Valley and into the southern Plains.

A pleasant night in progress across the Northern Middle Atlantic
region with only a few clouds across the N/W areas. An area of
smoke aloft drifted in before sunset leading to vivid red colors
for our area at sunset. High/mid level clouds will increase
later tonight as a cold front approaches the area. No rains are
expected. While we can`t rule out some patchy fog, right now
expect it won`t be particularly widespread or dense. Lows mostly
60s, with around 70 near the tidal waters, urban centers and
much of Delmarva.

Saturday start out with some sun, which likely helps push temps
well into the 80s by early afternoon. In fact, some spots could
touch 90, especially in the Delmarva. However, by this point the
front will be close enough which, when coupled with an
approaching shortwave embedded in the flow around the large
upper low to our north, should start to ignite showers and
storms, first across eastern PA, then spreading southeast from
there into NJ and the Delmarva as we head into the evening.
There are multiple scenarios about just how this plays out given
the relatively slow moving front and what appears to be several
pieces of upper level energy rotating through, but the bottom
line is that with significant afternoon CAPE and moisture,
somewhere in our region is likely to get severe weather, and
perhaps some flooding rains as well.

The severe threat is more obvious given the higher CAPE and
strong front moving in with plenty of shear aloft. As always in
our region, damaging winds are the main risk, but there is some
hint of supercell development, so we don`t have a zero tornado
risk. For these reasons, SPC has placed areas near and northwest
of the I-95 corridor in a slight risk for severe weather on
Saturday, with a marginal risk elsewhere.

The heavy rain threat may be a little more focused south and
east of areas that got hit hard last night, so am not quite
ready to pull the trigger on the flash flood watch since areas
that missed yesterday`s rain are quite dry. However, its notable
that HREF max QPF values have scattered areas of 2-4 inches
across most of the forecast area, and since its convection,
rainfall rates of 1-2 inches an hour are certainly not out of
the question. For now, we just have a marginal risk of excessive
rain from WPC, no doubt tempered by recent dry conditions.

After the front passes, lingering showers should gradually
diminish overnight Saturday, with lows in the 50s to low 60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The biggest change to the short term period is with the timing of
the cold front as it exits the region. As of now, the frontal
passage looks to be a bit slower as a weak area of low pressure
rides up along the front on Sunday. This may keep shower chances
continuing over the eastern half of the area through the first
half of Sunday before the front eventually moves out to sea by
the afternoon. As a result, a cool Sunday is on the table with
high temps only in the low to mid 70s. Clouds will be slow to
clear out especially for locales south and east, but should see
some sun break out for areas north and west in the afternoon.

By Sunday night, large and expansive Canadian high pressure will
build across the High Plains before moving into the Ohio Valley on
Monday. As it does so, the region will be located on the eastern
periphery of the high, resulting in seasonably cool, clear and dry
weather. With more in the way of sunshine expected on Monday, highs
will be a bit warmer compared to Sunday with most areas in the 70s.
Lows for both Sunday night and Monday night will range from the mid
40s to mid 50s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The long term period largely remains unchanged. The large area of
surface high pressure originating from Canada will gradually build
across New England, resulting in another period of prolonged east to
northeast surface flow. Towards the middle of the week, a stalled
boundary offshore could result in some increase in cloud cover and
few showers near the coast, but nothing of significance. Otherwise,
a cold front will move in from the north during the Thursday night
into Friday timeframe, however this front seems to lack any moisture
so as of now is expected to come through dry.

Temperatures for the week will remain seasonably cool with highs in
the 70s and lows in the 40s/50s. The exception is on Thursday ahead
of the cold front where high temperatures may top out in the low 80s
ahead of the front.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Tonight...Mostly VFR, with small chance of sub-VFR conditions
late in fog/stratus. Will not include in the TAF at this time,
as confidence is too low to warrant inclusion. Light S winds.
Low confidence on fog and stratus development.

Saturday...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 in the PM. Moderate confidence.

Saturday night...Showers and storms with intervals of sub-VFR
conditions in the evening give way to improvements later at
night. Winds becoming NW 5-10 kts. Moderate confidence.

Outlook...

Sunday...Lingering sub-VFR conditions possible, especially for
terminals south and east. A few showers possible.

Sunday night through Wednesday...VFR. No significant weather
expected.

&&

.MARINE...
Southerly flow increasing ahead of the next cold front will
likely bring low-end Small Craft Advisory conditions with gusts
to 25 kts and waves up to 5 feet to the ocean waters continuing
through late tonight. Some gusts and seas may touch SCA levels
during the day Saturday, but confidence is lower so kept SCA
confined to tonight. Winds shift northwest Saturday night behind
cold front but not expecting immediate SCA conditions yet.
However, showers and storms could necessitate Special Marine
Warnings later Saturday into Saturday evening on all waters,
including Delaware Bay where no SCA conditions are currently
expected thru Saturday night.

Outlook...

Sunday through Monday night...No marine headlines expected. Winds
between 10-20 kt with seas around 2-4 feet.

Tuesday through Wednesday...SCA conditions possible. Winds between
15-25 kt with seas around 3-5 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 until 6 AM EDT Saturday for ANZ450>455.

&&

$$

SYNOPSIS...DeSilva/Hoeflich/RCM
NEAR TERM...RCM/po
SHORT TERM...DeSilva/Hoeflich
LONG TERM...DeSilva/Hoeflich
AVIATION...DeSilva/RCM/po
MARINE...AKL/DeSilva/RCM
TIDES/COASTAL FLOODING...