490
FXUS61 KPHI 050609
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
109 AM EST Fri Dec 5 2025

.SYNOPSIS...
In the wake of an arctic cold front, arctic high pressure will build
into our region late tonight into Friday. The high then shifts
offshore into Friday night. Low pressure tracks well to our south
and southeast Friday afternoon and Friday evening with high pressure
arriving for much of the weekend. Another cold front however moves
through later Sunday. High pressure returns for Monday and Tuesday,
followed by another low pressure system around the middle of next
week.

&&

.NEAR TERM /THROUGH TODAY/...
For tonight, high pressure quickly moves overhead and lifts out
to the northeast. This will result in a relatively tranquil
night though with the coldest temperatures of the season so far.
Lows will be down in the single digits across the Poconos and
NW NJ. Elsewhere, temperatures will be in the mid to upper teens
and low 20s.

For tomorrow, an area of low pressure moves off the Outer Banks and
out to sea. The precipitation shield will clip the southern portion
of our area, and with an abundance of cold air in place, a period of
snowfall is anticipated. Measurable snowfall is expected from about
Wilmington to Atlantic City on southward. Snowfall will be rather
light, so impacts should be limited overall. Snow should begin
around 4-5 AM across the Eastern Shore and lower Delaware,
continuing through the mid to late morning. As the morning goes on,
warm marine air will try to infiltrate inland, resulting in a period
of mixing, and eventual change to rain near the immediate coast of
South Jersey and Delaware. The bulk of the precipitation will fall
between that 4-5 AM window and midday. Snowfall amounts did tick up
slightly, though currently have amounts below Advisory criteria.
Looking at around 1-1.5" across portions of Talbot and Queen Anne`s
County, with around 0.5-1" across central and southern Delaware and
the rest of the Eastern Shore. Lower amounts expected in northern
Delaware and South Jersey where amounts up to a half inch are
expected. Overall, just a light snow for early December. Cannot rule
out flakes around the Philadelphia area up into central Jersey, but
no accumulations are expected at this time. Below normal
temperatures expected tomorrow with upper 20s/low to mid 30s
expected.

While the bulk of the precipitation moves out by the early
afternoon, some lingering rain and snow showers may persist through
the evening and into the overnight hours. As temperatures fall
overnight and some showers remain, cannot rule out some patchy
freezing drizzle across portions of South Jersey and lower Delmarva
as model soundings show a warm nose at around 925 mb with some low-
level moisture in place. Temperatures fall into the low to mid
20s.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
Not quite as cold but temperatures still below average.

An upper-level trough across central into eastern Canada will remain
in place through the weekend. Several shortwaves rotating around
this feature will result in the trough or closed low meandering
around. These shortwaves will also drive some systems our way. An
axis of surface high pressure should be across our area to start
Saturday, however this then weakens with time. Given that the core
of the trough is to our north and northwest, temperatures while
still on the chilly/below average side, will not be quite as cold as
Friday. Given the presence of plenty of shortwave energy sliding by,
at least some cloudiness should prevail. Low-level moisture could be
trapped initially Saturday morning, and this may result in more
extensive low clouds before some breaks develop.

As we go through Sunday, an upper-level trough across much of
eastern Canada amplifies southward as stronger shortwave energy
rounds its base across the Great Lakes, with another one across the
southern states. Some guidance is sharpening the northern part of
the trough more due to stronger shortwave energy. This results in a
more organized surface feature into our area Sunday night. This
scenario would increase the chances for some light snow across
especially the northern half of the area, however there is a decent
amount of uncertainty with this. The associated front will deliver
another shot of reinforcing cold air during Sunday night.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Synoptic Overview...An expansive upper-level trough is forecast to
be across eastern Canada Monday which extends across the eastern
U.S. This trough may then pivot northward with additional energy
sliding southeastward from the Midwest to the Great Lakes Monday
night and Tuesday. The entire trough may then reload Wednesday and
Thursday into the East as strong shortwave energy amplifies it once
again. At the surface, weak low pressure and a cold front crosses
our area later Sunday with high pressure sliding across our area
later Monday into Tuesday. Low pressure tracks to our north later
Tuesday with its cold front shifting to our east. Another low may
then arrive late Wednesday into Thursday.

For Monday and Tuesday...An upper-level trough across eastern Canada
may tend to pivot northward with less cyclonic flow across the East.
However, a potentially strong shortwave slides southeastward on the
southern side of this trough across the Great Lakes region Monday
night into Tuesday, then crosses the Northeast during Tuesday. As
the axis of high pressure moves across our area Monday night,
temperatures are forecast to be very cold with lows in the teens
(single digits across the far north). Winds are anticipated to be
rather light and therefore little in the way of an added chill
factor. The surface high shifts offshore Tuesday as a clipper-type
system tracks mainly to our north. Its cold front however will cross
our area. The moisture with this feature looks limited and with a
quick forward motion to it, any precipitation at this time looks to
be rather light and spotty. The well below average temperatures are
forecast to continue on Tuesday.

For Wednesday and Thursday...The eastern Canadian upper-level low
looks to reposition itself as additional shortwave energy is
directed southeastward on its western and southern flank. This would
tend to support low pressure at the surface in the Midwest and Great
Lakes Wednesday which then moves our way into Thursday. There
remains uncertainty with this given all the moving pieces within the
parent upper-level trough, therefore did not deviate from NBM
guidance which essentially has PoPs at 20-30 percent across much of
the area. While some moderation in the temperatures are forecast
ahead of this feature, below average values are expected to
continue.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Through 12Z...VFR with gradual lowering and thickening of
clouds. North winds around 10 kt will gradually veer towards an
east-northeast direction around 5 kt becoming light and variable
at times. Moderate-high confidence overall.

Today...Anticipate VFR conditions to continue through the
morning hours as periods of light snow begin to occur near
KMIV/KACY and perhaps as far north as KILG. Flurries cannot be
ruled out as far north as KPHL and KPNE at times. By midday
(~18Z), anticipate ceilings to begin to lower to MVFR. East-
southeast winds around 5-8 kt. Low confidence overall.

Tonight...Anticipate mostly MVFR or IFR ceilings with
occasional visibility restrictions possible. Areas of drizzle or
freezing drizzle possible especially along the I-95 corridor
terminals and points south and east. Confidence in occurrence
is not high, so kept out of TAF for now. Winds light and
variable to near calm. Low confidence overall.

Outlook...

Saturday...Areas of sub-VFR ceilings possible early, otherwise VFR.

Sunday through Tuesday...VFR overall.

&&

.MARINE...
As of 1 AM, have allowed all Small Craft Advisories for the
Atlantic Ocean coastal waters and the Delaware Bay to expire as
winds and seas continue to fall below advisory thresholds.

For the remainder of the night and through the day today, no
further marine hazards are expected. Winds generally out of the
east-northeast around 10 kt and seas 2 to 4 feet. After an
initial onset of light snow this morning, periods of rain will
continue on the waters on today.

Outlook...

Saturday and Sunday...The conditions are anticipated to be below
Small Craft Advisory criteria, although winds increase later Sunday
night.

Monday...A period of Small Craft Advisory conditions possible.

Tuesday...The conditions are anticipated to be below Small Craft
Advisory criteria.

&&

.TIDES/COASTAL FLOODING...
As a result of the Full Moon on December 4th, spotty minor
tidal flooding is possible during the daytime high tides,
Friday through Sunday, along the southern New Jersey and
Delaware coasts, including parts of the lower Delaware Bay.
Flooding is generally expected to remain below advisory
criteria.

No tidal flooding is expected elsewhere.

&&

.CLIMATE...
Very cold temperatures are forecast for early Friday morning which
may challenge a few record lows.

Record Low Temperatures for December 5th...

SITERECORD/YEAR
Allentown (ABE)11/1926
AC Airport (ACY)11/1966
AC Marina (55N)15/1901
Philadelphia (PHL) 13/1886
Wilmington (ILG) 12/1926
Reading (RDG) 12/1926
Trenton (TTN) 10/1926
Mount Pocono (MPO) -2/1971
Georgetown (GED) 14/1966

&&

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

&&

$$

SYNOPSIS...DeSilva/Gorse
NEAR TERM...Hoeflich
SHORT TERM...Gorse
LONG TERM...Gorse
AVIATION...DeSilva/Fitzsimmons/Gorse/Hoeflich
MARINE...DeSilva/Fitzsimmons/Gorse/Hoeflich
TIDES/COASTAL FLOODING...PHI
CLIMATE...PHI