554
FXUS61 KPHI 101125
AFDPHI

Area Forecast Discussion
National Weather Service Mount Holly NJ
625 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 /12Z WEDNESDAY THROUGH SUNDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.

Today...VFR initially. Some brief MVFR CIGs possible at KRDG
until 14Z or so. A brief period of RASN, possibly mixed with
FZRA at KRDG-KABE from around 15Z-17Z, then precip changes to
RA. MVFR by 17Z. 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 until 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