248
FXUS61 KPHI 100704
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
204 AM EST Wed Dec 10 2025

.SYNOPSIS...
Low pressure tracks to our north during today with its cold front
crossing our region this evening. Another cold front moves through
Friday night, then weak low pressure may develop along it as it
tracks nearby Saturday night into Sunday. Arctic high pressure
centered well to our west builds into our region during early next
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Arctic high pressure has moved offshore, and temperatures are
markedly warmer now that they were 24 hours ago. A clipper system
over the Upper Midwest will dive into the Great Lakes later this
morning, then lifts to the north and east through central New York
and into northern New York and northern New England, along the
Canadian border this evening. This low then moves into the Canadian
Maritimes late tonight.

Warm air advection will be underway today as south to southwest flow
increases with the passage of this low. Precipitation develops later
this morning, initially over the southern Poconos and western
portions of the Lehigh Valley. Precipitation starts out as snow, and
will remain as snow across Carbon and Monroe counties for most of
the day. For Berks county, as well as Lehigh and Northampton
counties, snow will become a wintry mix, with a brief period of
freezing rain. With a light icing becoming likely, will go ahead and
expand the Winter Weather Advisory to include these counties. For
Carbon and Monroe counties, snow may become a wintry mix late with
some light icing. Overall, 1 to 3 inches of snow, with perhaps
locally as high as 4 inches above 1000 feet, will accumulate.

For the rest of the region, although a brief period of rain and snow
is possible for portions of northern New Jersey and the Lehigh
Valley, precipitation will will be plain rain. A warmer day on tap
with highs in the upper 30s to low 40s north and west of the Fall
Line, and and in the mid to upper 40s across southern New Jersey,
the Delaware Valley, and Delmarva.

Precipitation tapers off this evening, and conditions dry out
tonight. A cold front passes through the region behind the departing
clipper system. Winds turn to the west to northwest and increase to
10 to 15 mph with gusts up to 25 mph late tonight. Lows mostly in
the 20s to low 30s.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Plenty of cyclonic flow during Thursday and Thursday night given the
presence of an upper-level trough. A cold west-northwest wind will
be in place and areas of stratocumulus clouds should be around.
Model forecast soundings suggest steepening low-level lapse rates
during the day Thursday, and with cold air advection occurring
within strong flow, breezy to windy conditions look to occur. Peak
gusts should be up to 35 mph, although a little higher mainly in the
higher terrain of the Poconos. There will be a Great lakes response
and it is quite possible that some snow showers get into portions of
our Pocono region and northern New Jersey at times in the afternoon
and evening. Some of the guidance suggest that a narrow lake effect
streamer or two remains organized all the way into the Poconos and
even northern New Jersey. A streamer may be connected all the way
back to Lake Huron. Given the increased potential, started by
adding some slight chance to chance PoPs (20-30 percent) across
the northern areas. Some flurries cannot be ruled out even farther
south. Temperatures continue below average, and with the wind
factored in it will feel noticeably colder. The winds should
diminish some at night, however wind chills look to get down into
the teens by daybreak Friday (single digits in the Poconos and
northwest New Jersey).

Daytime Friday looks to be mainly dry as an axis of weak high
pressure slides across our area. Air temperatures look to be similar
to Thursday, which is several degrees below average. However, it
will not be as harsh as the winds will be turning lighter ahead of
the next system arriving Friday night. The trend in much of the
guidance has been to weaken the clipper as it crosses the
Appalachians, however there remains many moving parts in the active
flow and therefore kept what the NBM has (chance PoPs).

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Summary...Below to well below average temperatures with another
blast of arctic air late in the weekend and early next week.

Synoptic Overview...A series of stronger shortwaves sliding
across southern Canada and the northern tier of the U.S. will
continue to result in an upper-level trough as it pivots across
central to eastern Canada. This will amplify an upper-level
trough more than once across the Northeast and Mid-Atlantic
regions. This will keep temperatures on the cold side. This
looks to favor mostly clipper systems (quick moving) with their
associated cold fronts crossing our region. A stronger trough
however over the weekend may result in a weak surface low developing
along a trailing cold front with this low tracking near our area.

For Saturday and Sunday...A front may be stalled to our south. The
center of arctic high pressure across the Midwest and northern
Plains will gradually build eastward. Ahead of this feature, a
strong shortwave may end up amplifying into a strong upper-level
trough across the Northeast. This may result in a weak surface low
developing along the trailing cold front, which then tracks near our
area. Some guidance continues to be weaker with this feature and
therefore just has a front crossing our area, while others have a
zone of some stronger forcing with a more pronounced mid level wave.
Given the rather active upper air pattern with many moving pieces,
the guidance will likely continue to show varying solutions. As a
result, did not adjust from the NBM which paints chance PoPs
(peaking up to 40 percent) Saturday night into Sunday morning. Any
snowfall will depend on the track and strength of the wave and
therefore the zone of ascent. Temperatures still below average,
however Sunday is forecast to be several degrees colder than
Saturday.

For Monday and Tuesday...As the parent upper-level low starts
to exit, the center of arctic high pressure builds into our area
during Monday and Tuesday. This will result in very cold days with
temperatures well below average, particularly on Monday when a
breeze will add to the cold/chill factor. The northwesterly breeze
should then be easing as the high builds in more and therefore
erodes the pressure gradient. Another clipper system may approach
Monday night, however this feature will depend on the upper-level
trough amplifying once again as the surface high starts to weaken
and shift offshore.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Early this morning...Generally VFR. However, there will be a
brief area of MVFR CIGs from around 06Z-08Z across from KTTN to
KILG. S-SW winds 5 to 10 kt, except 10 to 15 kt with gusts up to
20 kt at KMIV/KACY.

Today...VFR initially. A brief period of RASN, possibly mixed
with FZRA at KRDG-KABE from around 14Z-16Z, then precip changes
to RA. MVFR by 16Z. For KTTN-KPNE-KPHL-KILG, VFR, lowering to
MVFR after 18Z in RA. For KMIV/KACY...Conds should remain VFR
throughout the day, though brief MVFR conds possible late in the
day in RA. S-SW winds 5 to 10 kt in the morning, increasing to
10 to 15 kt with 20 to 25 kt gusts. Moderate confidence overall.

Tonight...Any MVFR conds lift to VFR from 03Z-06Z, then VFR. SW
winds 5 to 10 kt, becoming W-NW 10 to 15 kt with gusts up to 20
kt after 06Z. Moderate confidence overall.

Outlook...

Thursday...VFR overall. A few snow showers possible near mainly KABE
in the afternoon and evening. West-northwest winds 15-20 knots
with gusts to around 30 knots, diminishing some at night.

Friday...Mostly VFR. A low chance for some light snow in the
afternoon and at night. Westerly winds may gust to 20 knots during
the day.

Saturday and Sunday...A period of sub-VFR conditions and some snow
possible Saturday night into Sunday morning. West to west-northwest
winds may gust to 20-25 knots.

&&

.MARINE...
South to southwest winds generally 20 to 30 kt with 35 to 40 kt
gusts on the ocean waters today through this evening. Gale warnings
remain in effect for this time, then a Small Craft Advisory will be
needed after the Gale Warning ends. SCA remains in effect for
Delaware Bay for today and tonight as winds will generally range
from 15 to 20 kt with 25 to 30 kt gusts.

VSBY restrictions in rain by this afternoon and through this
evening.

Outlook...

Thursday...Gale force wind gusts possible. The winds should diminish
some later at night.

Friday...The conditions may remain below Small Craft Advisory
criteria.

Saturday and Sunday...Small Craft Advisory probable. Gale force wind
gusts possible, mostly during Sunday.

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Winter Weather Advisory from 6 AM this morning to 6 PM EST
     this evening for PAZ054-055-060>062.
NJ...None.
DE...None.
MD...None.
MARINE...Small Craft Advisory until 6 AM EST Thursday for ANZ430-431.
     Gale Warning until 10 PM EST this evening for ANZ450>455.

&&

$$

SYNOPSIS...Gorse
NEAR TERM...MPS
SHORT TERM...AKL/Gorse
LONG TERM...Gorse
AVIATION...Gorse/MPS
MARINE...Gorse/MPS