928
FXUS61 KPHI 211834
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
134 PM EST Fri Nov 21 2025

.SYNOPSIS...
A developing low pressure system will pass through the Mid-
Atlantic tonight and then offshore by Saturday. This low
pressure system will be followed by high pressure building into
the region through early next week. A strong frontal system then
looks to impact the area during the middle to end of next week.

&&

.NEAR TERM /THROUGH SATURDAY/...
High pressure over the area weakens as it slides offshore.
Several shortwaves will pass through the region through this
evening, and this will keep skies cloudy. Cloud bases may lift
this evening, and could even scatter out a bit.

Weak low pressure currently over Nebraska and Oklahoma will
track east through the Midwest and Ohio Valley tonight, and will
be near the Appalachians after midnight tonight. This low will
slowly work its way through the Mid-Atlantic and Delmarva
Peninsula Saturday morning. The low will then be some 200 miles
south and east of Nantucket Island by Saturday afternoon. Weak
upper level troughiness with strong shortwave energy passes
through the region late in the day as surface high pressure
builds in from the west.

Rain develops over the area late tonight and continues through
Saturday morning. Most of the rain will taper off around midday,
though some lingering rain may persist over the coastal areas
as the low departs. Conditions then improve late. Overall, can
expect 1/4 to 1/2 inch QPF throughout, though less than 1/4 inch
north of I-78 and closer to 1/2 inch over Delmarva.

Fairly mild for this time of the year with lows in the low to
mid 40s tonight, and then in the low to mid 50s on Saturday.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
A high pressure system continues to build in from the south and west
Saturday night with cooler drier air in place. Lows Saturday night
will be in the mid 20s to mid 30s with a mostly to partly clear sky.

Our high pressure system sticks around for Sunday which leads to a
dry day with a mostly clear sky for many with some more clouds as
you head north but these areas still look to be mainly partly
cloudy. Highs are in the mid 40s to mid 50s. A weak cold front moves
through Sunday night but does not result in much aside from a light
passing shower. Any precip potential looks pretty limited.

On Monday, our surface high remains in place which keeps the day dry
and mainly clear. Some clouds start to filter in by the later
afternoon hours from the west ahead of our next system. Highs on
Monday are in the mid 40s to mid 50s.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
We stay dry Monday night with increasing clouds across the area. Our
high pressure system exits to the east. There are then two low
pressure systems that we see bring some precip to the area. One
moves into the Great Lakes Region and then eventually into Canada
while the other moves out of the Tennessee River Valley area and
into the Mid-Atlantic region. What this means is that we start to
warm up ahead of the systems with multiple rounds of rain which is
followed by two cold fronts.

For the more specific details, we start to see warm air filter in
Tuesday into Wednesday. Highs on Tuesday are mainly in the low 50s
to low 60s. By Wednesday, highs are mainly in the low to mid 60s. As
the warm moist air filters in, we also see increasing rain filling
in by midday. The best coverage of the rain looks to be Tuesday
night where PoPs are around 70%. Our first cold front with the low
moving through the Mid-Atlantic region moves through Wednesday which
continues to lead to periods of rain or rain showers. The cold front
with the low in Canada then passes through Wednesday night into
Thursday morning which also continues to keep periods of rain or
rain showers going through Wednesday night. Cold air filters in
behind the cold fronts and results in highs for Thanksgiving in the
low 40s to low 50s. One key note is that given this being
towards the end of the long term period, there is still some
uncertainty with the timing of the systems and their cold
fronts. Some deterministic guidance does look to keep rain
around on Thanksgiving with the systems being slower. Regardless
of the timing of the cold fronts, behind them is notable cold
air advection.

&&

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

Rest of today...MVFR CIGs, with some improvements to VFR along
and east of the I-95 corridor terminals late. SW winds less than
10 kt. Low confidence.

Tonight...Any VFR CIGs will lower to MVFR/IFR by 04Z. RA
develops with MVFR/IFR VSBYs. LGT/VRB winds. Moderate
confidence.

Saturday...IFR in the morning, briefly lifting to MVFR, then to
VFR after 18Z. Light NE winds in the morning, becoming NW less
than 10 kt after 18Z. Moderate confidence.

Outlook...

Saturday night through Monday night...VFR. No significant weather.

Tuesday...VFR to start, with sub-VFR conditions possible later in
the day in periods of light rain.

Tuesday night through Wednesday...Sub-VFR conditions possible in
periods of light rain.

&&

.MARINE...
Conditions will remain below Small Craft Advisory criteria for
the rest of the day today, tonight, and Saturday.

Southwest winds 10 to 15 kt through this evening, becoming
light and variable late tonight. North winds pick up at 10 to 15
kt with gusts up to 20 kt late Saturday morning, backing to the
northwest late in the day.

Visibility restrictions in rain developing after midnight
tonight and continuing through most of Saturday.

Outlook...

Saturday night through Wednesday...Conditions are anticipated to be
below SCA criteria.

&&

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

&&

$$

SYNOPSIS...Fitzsimmons/Guzzo
NEAR TERM...MPS
SHORT TERM...Guzzo
LONG TERM...Guzzo
AVIATION...Guzzo/MPS
MARINE...Guzzo/MPS