652
FXUS61 KPHI 051421
AFDPHI

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

.SYNOPSIS...
High pressure will shift offshore into tonight. Meanwhile, a
low pressure system will be lifting off the coast of the
Carolinas and further out to sea. The next cold front is
expected to cross our region Sunday into Sunday night. In the
wake of that front, high pressure builds in for the first half
of the week, followed by another low pressure system approaching
our region Wednesday into Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 915 AM, snow continues across all of our Delmarva zones
and into far southern New Jersey. The intensity thus far has
been on the light side. Snowfall reports are as much as 1.6
inches in Sussex County, Delaware. The more organized forcing
appears to be weaken some as radar trends show the snow shield
becoming weaker and more fragmented on the south and
southwestern flanks. There still remains a more organized band
through from the central Maryland Eastern Shore to central
Delaware to Cape May County in New Jersey. Increased snow totals
a bit mostly in southern Delaware given a few reports so far.
DelDOT cameras also show the light snow across the Delaware
Beaches has mixed with or even changed to rain. Quite the
gradient northward with much drier air and a clear sky currently
over our northern areas. Clouds are expected to increase in
these areas through the day.

Otherwise, snowfall amounts are still anticipated to remain
below advisory thresholds. Further north, occasional flurries
and snow showers may reach as far north as the I-78 corridor by
late day, but no accumulation in these areas are expected. The
bulk of precipitation should come to an end by mid to late
afternoon. High temperatures will range between the upper 20s to
upper 30s for most, with lower 20s in the Poconos and lower 40s
along the coast.

Tonight, low pressure near Hatteras will continue to track northeast
into the western Atlantic. As it does so, an inverted surface trough
extending out of the north side of the low will pivot through the
area. With temperatures expected to fall into the mid 20s to low
30s, residual low-level moisture trapped under an inversion, and a
subtle warm nose located just above the surface, many forecast
soundings suggest pockets of drizzle and/or freezing drizzle are
possible through the evening hours. Greatest potential for
occurrence is for locales along and southeast of the I-95 corridor,
before winding down come Saturday morning.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
The big story in the short term will be the cold front crossing
through our region late Sunday into Sunday Night.

With the main trough axis to our northwest Saturday and Sunday,
surface winds will shift to southwesterly allowing a brief
warming trend. Temperatures will be about 5 to 10 degrees below
normal for this time of year, but this will be about 10 degrees
warmer than temperatures today.

As we go through Sunday, an upper-level trough across much of
eastern Canada amplifies southward. The associated cold front is
expected to cross our region late Sunday into Sunday night.
Despite the weak southerly/southwesterly return flow Saturday
into Sunday, moisture will likely be limited. There is a 20 to
30% chance for light snow with the frontal passage, primarily
across East Central PA and northern NJ.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
The two key messages in the long term are the potential for much
colder than normal temperatures Monday into Tuesday, and the
next low pressure system approaching our region Wednesday into
Thursday.

In the wake of the cold front, temperatures, especially Monday
and Monday Night, will be well below normal, as much as 20
degrees below normal. For now, have stayed pretty close to the
blend of models. However, there are some factors suggesting that
guidance could have a warm bias on Monday night/Tuesday morning.
During that time, the surface high will be very close to our
region, with clear skies (at least to start the night) and very
light winds. These types of efficient radiational cooling
patterns tend to end up colder than the median blend of
guidance. However, some guidance suggests that clouds could
start to build in as early as the pre-dawn hours on Tuesday
Morning, which could limit or cut short the radiational
cooling. While it doesn`t look like we will be getting close to
any record lows, in some areas our current forecast is only 5 to
10 degrees away from Cold Weather Advisory criteria.

For Wednesday and Thursday...The eastern Canadian upper-level low
looks to reposition itself as an additional shortwave trough
digs 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 the blend of guidance. PoPs, especially
with the Wednesday night period are higher with the latest
guidance as compared to yesterday, but there remains
considerable uncertainty. While some moderation in the
temperatures are forecast ahead of this feature, below average
values are expected to continue.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR ceilings spread northward and gradually lower from
south to north. MVFR ceilings from KILG to KMIV and KACY with
time, and also at these terminals a period of light snow with
visibilities dropping to MVFR or IFR. Flurries cannot be ruled
out as far north as KPHL and KPNE at times. During this
afternoon, anticipate remaining VFR ceilings lower to MVFR.
East-northeast winds 5-8 knots becoming east-southeast. Low
confidence overall.

Tonight...MVFR early lowers to IFR ceilings with occasional
visibility restrictions. Some drizzle or freezing drizzle
possible especially along the I-95 corridor terminals and
KMIV/KACY. Winds light and variable to near calm. Low
confidence.

Outlook...

Saturday...Becoming VFR once lingering low ceilings dissipate

Saturday Night through Tuesday...Prevailing VFR.

&&

.MARINE...
No marine headlines are in effect through tonight. East-northeast
winds around 10-20 kt are expected to persist through this
afternoon, before settling out of the north around 5-10 kt tonight.
Seas of 2-4 feet.

Periods of light snow expected through mid-morning, before changing
over to light rain for the remainder of the afternoon. Occasional
drizzle may continue into tonight.

Outlook...

Saturday through Sunday...Winds and seas will stay below SCA
criteria.

Sunday Night through Monday...SCA conditions are expected and gale
conditions are possible behind a cold front Sunday Night that will
also bring an abrupt shift to northwesterly winds. There is a 20 to
40% chance that gale force conditions will develop in this period.

Tuesday...Late Tuesday, wind gusts near or above 20 kt are expected,
but we are currently forecasting winds to stay below SCA criteria.

&&

.TIDES/COASTAL FLOODING...
As a result of the Full Moon on December 4th, we are monitoring
for minor tidal flooding during the daytime high tides through
Sunday. This is primarily for the NJ and DE coasts and lower
Delaware Bay. Previous forecast is tracking well, so expect that
the Friday tides will fall short of advisory levels. However, it
does appear that tidal departures will increase slightly
Saturday into Sunday, increasing the chance for minor tidal
flooding especially for the southern New Jersey and Delaware
coasts, including parts of the lower Delaware Bay.

No tidal flooding is expected elsewhere.

&&

.CLIMATE...
As of 4:30 AM Friday, Mount Pocono has tied its record low with
a low temperature of -2 degrees. We will continue to monitor
through the morning if it drops further and if any other climate
site reaches its record low temperature.

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


Another cold night/morning is possible Monday Night into Tuesday
Morning. At this point, we aren`t forecasting to break any
record lows. Below are the record lows for December 9.

SITERECORD/YEAR
Allentown (ABE)      7/2002
AC Airport (ACY)     6/1968
AC Marina (55N)      5/1876
Philadelphia (PHL)   6/1876
Wilmington (ILG)    13/1960
Reading (RDG)        0/1989
Trenton (TTN)       12/2002
Mount Pocono (MPO)  -1/1902
Georgetown (GED)    10/1976

&&

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

&&

$$

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