176
FXUS61 KPHI 020918
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
418 AM EST Tue Dec 2 2025

.SYNOPSIS...
Low pressure tracks northeast towards our area Tuesday into
Tuesday night, bringing widespread precipitation. High pressure
and below normal temperatures return for the middle of the
week. Another cold front will track through the region Thursday
night, with high pressure building back in thereafter. Another
system may impact the region Friday night into the weekend,
before high pressure builds back in for early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The low pressure system remains the main story for the near term
period as it approaches the area this morning and then off the coast
by this afternoon, which will bring widespread precipitation to the
region, including the first accumulating snowfall to portions of the
area. This low will make its closest approach to the area as it
passes offshore this afternoon, and begin departing to the northeast
tonight.

In terms of the details with this system, the forecast largely
remains on track. Light precipitation looks to begin pushing into
the area over the next few hours but the majority will hold off
until after daybreak this morning. PoPs gradually increase to around
30-50% for the remainder of the early morning hours. Quickly after
daybreak, the precipitation becomes widespread across the area with
the highest PoPs (90-100%) being during the daytime hours today.

Observations indicate that temperatures have already hit their lows
early this morning and have begun to increase with subtle warm air
advection ahead of the approaching system. Continuing through the
day today, the onshore flow and warm marine influence with the
surface low drawing near will impact the temperature profiles. For
perspective on this, high temperatures today will be near or a
couple degrees above freezing in the Poconos, mid 30s to near 40
degrees northwest of the fall line, low 40s along the I-95 corridor,
and in the mid 40s to low 50s in Delmarva and along the coastal
areas.

As a result, with more warm air in place at the onset of the
precipitation, the rain/snow line still looks likely to be near or
northwest of the I-95 corridor at the onset of precipitation. A few
flakes or some sleet at the onset can`t be completely ruled out for
areas southeast of the I-95 corridor but the frozen precipitation
won`t last long with the warming trend. By mid-morning, the
rain/snow line is inching north of I-78. During the afternoon, the
rain/snow line has the potential to reach into the Poconos and parts
of northwest NJ. With the aforementioned highs being near/just above
freezing in the Poconos, there is even the potential for mixing in
the higher elevations of these areas above 1,500 feet.

Regarding more details about the precipitation accumulation, QPF has
remained about the same with the latest updates. Totals continue to
range from 0.50-1.00" with localized amounts to 1.25" with the
greatest across the coastal plain and least farther inland north of
I-78.

As for snowfall accumulation, the forecast has remained about the
same with this update. The probability for plowable snow (2" or
more) remains high (60-90%) in the Poconos and areas along and north
of I-78. As you head well south and east of I-78, the potential for
plowable snow quickly decreases to near 0% for the I-95 corridor.
Our latest forecast includes snowfall amounts of a few tenths of an
inch for the very NW portion of the I-95 corridor, up to an inch for
areas just northwest of there, and in the 1-3" range for the I-78
corridor and NW NJ. Higher elevations (especially 1,500 feet and
higher) in NW NJ and across the Pocono Plateau have potential for
snowfall in the 3-6" range.

Outside of potentially the Poconos and perhaps the higher elevations
in NW NJ, the snow that falls will then be melting through the day
with the change to all rain and warm air moving further inland.
During the transition period from snow to rain, some sleet is
possible briefly. Due to the stronger signal of warmer air advecting
in, the transition zone from snow to rain may not be as clean. There
is now the potential for a light accumulation of ice from freezing
rain in the transition zone northwest of the I-95 corridor. The ice
accumulation looks to be a light glaze.

The Winter Weather Advisory for the southern Poconos and Sussex
County NJ is unchanged, remaining in place through the day today, as
snow and/or mixed precipitation will continue in this area until the
system departs this evening.

The Winter Weather Advisory for the next tier of counties
southeastward in northern NJ and the I-78 corridor and down into the
far northwestern reaches of the Philly metro, has been expanded to
include Somerset County in New Jersey. These are the areas most
likely to experience a troublesome Tuesday morning commute, with
snowfall up to the 1-3" range as well as light glaze of ice from
freezing rain.

For the remainder of the region that will see all rain or a change
to rain early on will have a good soaking all-day type of rain. A
few precipitation and/or snowfall records could be challenged. See
the Climate section below for more details on the records.

Once the low departs late this evening, a high pressure system will
build in from the southwest. This will lead to drier conditions
through tonight. Lows tonight are in the 20s for most, which may
lead to some black ice issues where any slushy snow melt refreezes
on roadways (especially north of I-78).

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
By Wednesday morning, the axis of the H5 trough that will lead to
Tuesday`s widespread precipitation will be in the Gulf of Maine
vicinity, rapidly lifting northeast away from the area. A subtle
upper-level ridge axis will shift eastward across the area through
the day Wednesday. Wednesday night into Thursday, enhanced
southwesterly flow aloft will begin to overspread the area as a
trough digs southeastward over portions of Ontario and eventually
Quebec. The trough axis will pass to the north/glance the region
Thursday. Subtle height rises will follow with flow aloft becoming
zonal Thursday night. At the surface, high pressure will build in
from the west on Wednesday. A surface low will pass well to the
north of the area on Thursday with a strong trailing cold front
moving through by Thursday evening.

Wednesday should be a partly to mostly clear day. Highs will range
from the mid 30s across eastern PA and northern NJ to the low 40s
across southern NJ and the Delmarva. Wednesday night will feature
increasing clouds from northwest to southeast as the cold front
begins to approach the region. Lows will be in the low-mid 20s
across most of eastern PA and NJ, with upper 20s to near 30 for the
coastal plain, urban corridor, and Delmarva.

Thursday will be partly to mostly cloudy ahead of the front. While
not explicitly mentioned in the forecast at this time, a couple of
snow showers could occur with the frontal passage across the
Poconos. If this were to occur, accumulation amounts would be
light. Otherwise, it looks to remain dry. Will defer to future
shifts on potential inclusion of PoPs for this region. Highs
will generally be in the 30s northwest of I-95 and 40s
southeast. Skies should clear behind the front, but breezy
northwest winds will ensue, so it will be quite chilly.

With the cold post-frontal airmass in place, decreasing winds, and
partly to mostly clear skies, the stage will be set for a very cold
Thursday night. Lows are expected to be in the single digits across
the Poconos and into far northwestern NJ, the teens across the
remainder of eastern PA and NJ, and the low 20s across the
Delmarva.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Friday looks to start with high pressure centered over our area
under zonal flow aloft. Deterministic guidance still shows the
potential for a weak impulse aloft to track through the region
Friday night into Saturday. The surface high will shift
eastward and off the coast Friday night into Saturday. Ensemble
guidance still suggests the possibility of surface cyclone
formation across the Carolinas, though consensus remains that it
will be a weaker storm that will stay south of us, with only a
glancing blow. We continue to have a chance (30-50%) PoPs
across most of the area for Friday night, with the greatest
chances across southern DE and far southeastern NJ. These
ultimately may continue to come down, but trends will be
monitored in the coming days as this potential storm system gets
closer in time. The airmass in place will be cold enough that
any precipitation that does fall across the area with this
system would have the potential to be of the wintry variety.

Regardless of precipitation chances for Friday night into Saturday,
the pattern favors well below average temperatures. In fact,
temperatures may remain below freezing on Friday for most of eastern
PA and northern NJ, and only reach the mid 30s across the Delmarva
and into southern NJ. Saturday and Sunday look to remain below
average, though slightly warmer than Friday. Another cold front
could bring at least low precipitation chances and a renewed shot of
cold air Sunday night into Monday.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Early this morning...Primarily VFR. Chance (20-40%) of MVFR
conditions after 10Z as rain and snow begin to move in though things
come down more towards daybreak and after. East-northeast winds
around 5 knots or less. Moderate confidence.

Today...IFR/LIFR conditions develop between 11z-15z. High confidence
in all rain at KACY/KMIV. The trend as of this morning has been
warmer and slower with precipitation moving in.
This will result in pretty much all rain for KILG/KPHL and have
taken snow out of the TAF for now. Cannot rule out a few flakes/mix
at onset, but would expect a quick flip to rain once precipitation
begins. For KPNE/KTTN, expecting a longer period of snow and/or mix,
but a flip to all rain should occur by 12z-14z. A period of all snow
expected at KRDG/KABE from about 10z-14z before mixing occurs and
eventual flip to all rain after 18z. High confidence in at least IFR
through the morning with the potential (25-35%) in prevailing LIFR.
Moderate confidence in timing of precipitation type changes. Winds
will be out of the east/northeast around 5-10 kt, expecting to shift
to north/northwest between 18z-21z. Moderate confidence in timing of
wind shifts.

Tonight...Conditions gradually improving with rain coming to and end
though MVFR/IFR expected to start, with VFR anticipated to return
between 03-06Z. Northwest winds around 10 knots with gusts up to 20
knots possible. Moderate confidence.

Outlook...

Wednesday through Wednesday Night...VFR. No significant weather.

Thursday...VFR. Gusts near 20 kt expected out of the
west/northwest

Thursday Night through Friday...VFR. No significant weather.

Friday Night through Saturday...Restrictions possible (40-60%)
with rain and snow showers moving through.

&&

.MARINE...
No marine hazards are anticipated through early this morning with
seas 2-3 feet and winds out of the east to then southeast gusting to
10-20 knots.

Winds and seas will then increase later this morning. Winds will
gust to 25-30 knots and flip to be out of the north to northwest by
this evening. Occasional gusts to 35 knots are possible on the ocean
zones tonight. Seas will reach 5-7 feet tonight as well. As a
result, a Small Craft Advisory is in effect beginning at 10 AM today
for the Atlantic Ocean coastal waters and at 3 PM for the Delaware
Bay. The SCA will continue through tonight for all coastal
waters.


Outlook...

Wednesday...SCA conditions linger into the first part of the
day. While winds are expected to have subsided, seas of 4-6 feet
are expected in the morning, decreasing to 2-4 feet through the
day.

Wednesday night...No marine headlines are anticipated with winds
below 25 kt and seas below 5 feet.

Thursday through Thursday night...SCA conditions are possible with
northwest winds 15-25 kt and seas 3-5 feet.

Friday through Saturday...No marine headlines are anticipated with
winds below 25 kt and seas below 5 feet.

&&

.CLIMATE...
Widespread moderate to heavy precipitation is expected on
Tuesday, December 2nd. A few daily precipitation and/or snowfall
records could be challenged. Records for our climate sites are
listed below:

Record Precipitation (Rainfall)
                       December 2
Site                  Record/Year
Allentown (ABE)        0.86"/1934
AC Airport (ACY)       1.03"/1996
AC Marina (55N)        1.18"/1929
Georgetown (GED)       1.11"/1974
Mount Pocono (MPO)     3.56"/1996
Philadelphia (PHL)     1.48"/1986
Reading (RDG)          1.29"/1981
Trenton (TTN)          2.13"/1986
Wilmington (ILG)       1.27"/1991

Record Snowfall
                       December 2
Site                  Record/Year
Allentown (ABE)         3.6"/1952
AC Airport (ACY)           T/2019*
Philadelphia (PHL)      2.0"/1903
Reading (RDG)           6.0"/1929
Trenton (TTN)           3.0"/1903
Wilmington (ILG)        1.0"/1952

*Multiple years with a Trace.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory until 1 PM EST this afternoon for
     PAZ060>062.
     Winter Weather Advisory until 10 AM EST this morning for
     PAZ101-103-105.
     Winter Weather Advisory until 6 PM EST this evening for PAZ054-
     055.
NJ...Winter Weather Advisory until 7 PM EST this evening for NJZ001.
     Winter Weather Advisory until 1 PM EST this afternoon for
     NJZ007-008.
     Winter Weather Advisory until 10 AM EST this morning for
     NJZ009-010.
DE...None.
MD...None.
MARINE...Small Craft Advisory from 3 PM this afternoon to 6 AM EST
     Wednesday for ANZ430-431.
     Small Craft Advisory from 10 AM this morning to 1 PM EST
     Wednesday for ANZ450>455.

&&

$$

SYNOPSIS...MJL
NEAR TERM...AKL/Guzzo
SHORT TERM...Cooper/MJL
LONG TERM...Cooper/MJL
AVIATION...AKL/MJL
MARINE...AKL/MJL
CLIMATE...