pa discuss
Office: CTP
FXUS61 KCTP 061135
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
635 AM EST Sat Dec 6 2025
.SYNOPSIS...
* Mostly cloudy and not as cold to start the 1st weekend of
December
* Periods of light snow over the western and northern
Alleghenies this weekend; minor accumulation expected Sunday
* Cold weather pattern with clippers cascading east of the
Rockies provides more opportunities for snow next week
&&
.NEAR TERM /THROUGH TONIGHT/...
Areas of -ZL remain possible across the Laurel Highlands early
this morning; SPS valid until 12Z/7AM. Sfc obs/RWIS data suggest
coverage will remain limited, but still can't rule out a few
icy spots.
Cloudy and much warmer overnight period with daybreak readings
15 to 25 degrees warmer across the northwest 1/2 of the CWA.
The not as cold trend translates through the afternoon with fcst
highs in the 30-40F range or +10-15 degrees higher than
yesterday.
Modest lift along and ahead of weak front tied to sfc low over
Hudson Bay...followed by a short window of marginally favorable
WNWly cross-lake wind will result in light, lake/terrain
enhanced snow/snow showers spilling southeast/downwind of Lake
Erie across the NW mtns along the Allegheny Front into the
Laurel Highlands later this afternoon into the early evening.
Little to no accumulation is expected. Light snow will
reposition along the lakeshore and come to an end in the NW mtns
early tonight as the low level wind trajectory backs to the
WSW.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Split/northern stream trough swings through on Sunday and
brings another period of snow primarily to the NW Alleghenies
during the late afternoon into the first part of Sunday night.
Snowfall amounts from NBM, WPC and RRFS have all trended a bit
lower in the 1-2" range over Warren/McKean and C-1" elsewhere
along the Allegheny Front. Don't expect much more than a few
flurries or spotty fzdz into late Sunday night followed by
gradual clearing into early Monday morning behind increasing
large scale subsidence and much drier air poised to accompany
modified arctic high pressure eastward from the Midwest.
1030mb high migrating over CPA will ensure dry and cold wx on
Monday. Daytime highs are fcst to stay below the freezing mark.
Monday night looks bitter cold to frigid with lows in the
single digits to low teens.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
High pressure shifts east of the I95 corridor by Tuesday
afternoon as another northern/split stream trough traverses the
Great Lakes. This feature looks to brush the northern tier with
another light snowfall.
The large scale upper flow will become more amplified for the
middle to late week period with a persistent trough in the east
and ridging over the Rockies and Western States.
Several clippers cascading eastward from the Rockies will
provide more opportunities for winter wx (mainly snow) from
Wednesday into next weekend.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Southwesterly flow increases through the morning ahead of a weak
cold front and MVFR ceilings will rise to VFR. MVFR ceilings
should redevelop later this morning at BFD and during the
afternoon at JST, AOO, and UNV. A few snow showers will be
possible this afternoon at BFD as the cold front moves through
and may cause brief visibility restrictions.
Northwesterly flow behind the front will keep low stratus in
place overnight, with ceilings lowering to IFR at BFD and JST.
Model RH profiles suggest that the MVFR stratus deck should
eventually reach IPT, but confidence is low. MDT and LNS will
remain VFR with clearing skies.
Outlook...
Sun...A compact but more amplified upper level trough with a
preceding low level south to southwesterly wind max will likely
bring a 4 to 6 hour period of mainly light snow with IFR vsbys
and MVFR to IFR CIGS (targeting mainly central and northern PA)
late Sunday/Sunday night.
Mon...Mainly VFR
Tue-Wed...Restrictions possible with snow, especially across the
northern half of Pennsylvania, as multiple low pressure systems
track through the northeastern US.
&&
.CLIMATE...
* Record low temperature of -8 degrees was set at Bradford on 12/5.
The previous record was 0 degrees set in 2007.
* Record low temperature of 12 degrees was set at Altoona on 12/5.
The previous record was 13 degrees set in 1966.
* Astronomical winter (solstice) begins at 10:03 a.m. on Sunday,
December 21st
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...Bauco
CLIMATE...Steinbugl
Office: PHI
FXUS61 KPHI 061737
AFDPHI
Area Forecast Discussion
National Weather Service Mount Holly NJ
1237 PM EST Sat Dec 6 2025
.SYNOPSIS...
Through the day today, our region will be sandwiched between the
departing low pressure system moving further off shore and the
next approaching cold front in the Great Lakes Region. By Sunday
night, that cold front will cross through our region. In the
wake of that front, high pressure builds in for the first half
of the work week. The second half of the week could be active,
with potentially two low pressure systems getting close to the
region in that period.
&&
.NEAR TERM /THROUGH TONIGHT/...
A very complex forecast continues this morning as periods of light
freezing drizzle, drizzle, light snow, and sleet have been observed
along the I-95 corridor. The surface low that brought some light
snow to the area yesterday, continues to pull away, however, a
residual weak surface trough lies just off the coast of New Jersey.
This trough is enhancing lift across portions of the area this
morning. As it does so, low-level moisture remains trapped under an
inversion around 960 mb which is shown in the PHL ACARS sounding.
Temperatures at the inversion level have been mostly below 0C,
however gradual warming above 0C is occuring, where light snow is
now transitioning to pockets of drizzle and/or freezing drizzle.
Perhaps a light glaze of ice accretion is possible where freezing
drizzle occurs, but the overall aspect is that this will be rather
isolated in nature. Also, a light dusting of snow is possible up in
the higher terrain of north Jersey. As a result, a Special Weather
Statement is in effect through 8 AM for portions of the area which
may continue to observe isolated areas of hazardous travel for the
next several hours. Light frozen precipitation should come to an end
thereafter once surface temperatures warm above freezing.
Improving weather conditions are then expected as the day progresses
with the main trough axis approaching from the west. At the surface,
the area will be caught in between systems, resulting in a weak,
brief period of ridging. As a result, mostly cloudy to overcast
skies this morning, will begin to lift and scatter out this
afternoon. Temperatures will moderate some with winds having a more
westerly component to them, where highs are to range from the mid
30s to mid 40s. Tonight, skies will be mostly clear early, but some
high level clouds will filter in after midnight as another weak
impulse approaches. With winds generally less than 5 mph under
mostly clear skies, radiational cooling appears optimal. Lows look
to range from the upper teens to upper 20s for most. For areas which
still have snow on the ground from recent snowfall, temperatures may
end up being much lower than what is currently forecast.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY/...
A cold front is expected to cross our region Sunday
evening/overnight, ushering in much colder air.
The biggest change from previous model runs is that the
associated trough isn't as amplified. What this means for
ultimate impacts is the chance for precipitation has decreased
and the blend of guidance for wind speeds/gusts has decreased
slightly.
Stayed close to the blend of guidance for the chance for
precipitation, which now means that we don't have any mention of
precip in our area. However, will be keeping a close eye on
guidance trends especially for the Poconos.
For winds however, I included wind/wind gust speeds on the
higher end of the blend of guidance for the 12 hours following
the frontal passage. This is more in line with model soundings
showing a potential for wind gusts above 30 mph.
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 likely be
situated over our region, with clear skies and very light winds.
These types of efficient radiational cooling patterns tend to
end up colder than the median blend of guidance. Previous model
runs were depicting the potential for clouds to build in Tuesday
morning, but with the latest guidance, the chance has
decreased. None the less, with the latest guidance, even if we
verify at the 10th percentile of guidance for min temperatures,
we should still stay above cold weather advisory criteria.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The long term period is still rather muddled in terms of confidence
in model runs owing to a split flow pattern and minor differences in
the timing and evolution of the two low pressure systems that are
possible at the end of the week.
Beginning Tuesday night, we will be watching a shortwave
trough dig southeastward across the Northern Plains and into the
Great Lakes region. It should pivot through or just northwest of
the region on Wednesday. In a sharp contrast from previous model
runs, some guidance is depicting this a weak and fast moving clipper
type system, while other guidance continues to show it interacting
with a closed low over Canada, resulting in a broad trough setting
up over the eastern seaboard. Depending on how quickly that system
moves out, a second short wave trough could dig through the
Dakotas/Minnesota area into the Mid Atlantic by Friday.
Using a blend of guidance shows a broad chances for precipitation
from Wednesday through Friday. However, I don't expect the second
half of the week to be a washout; this is more an artifact of timing
differences between guidance. It is more likely that if we see any
precipitation, it will come in two distinct periods with the two
different systems.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Through 00Z...MVFR and even brief periods of IFR ceilings
remain for KILG, KMIV, and KACY. Some drizzle continues to cause
MVFR visibility restrictions for KPHL as well. Any residual
drizzle should dissipate, with ceilings lifting/scattering out
by 19-21Z. VFR for all terminals thereafter. West wind 5-10 kt.
Moderate confidence overall. Low confidence in exact timing of
improvement to VFR given the persistence of low ceilings and
drizzle.
Tonight...VFR with mostly clear skies. West wind 5 kt or less
becoming light and variable with calm periods. High confidence.
Sunday...VFR. Southwesterly wind 5-10 kt. High confidence.
Outlook...
Sunday night through Tuesday...Prevailing VFR.
Wednesday...Sub-VFR conditions will be possible with a chance
(20- 40%) of rain.
&&
.MARINE...
No marine headlines are in effect through tonight. North-northeast
winds around 5-10 kt this morning, will settle out of the northwest
this afternoon into tonight around 10-15 kt. Occasional gusts up to
20 kt possible tonight. Seas of 2-4 feet. A chance for drizzle this
morning, otherwise fair weather.
Outlook...
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...wind and seas should stay below SCA criteria.
Tuesday Night through Wednesday...SCA conditions are likely with
wind gusts up to 30 KT and elevated seas up to 8 ft on the coastal
waters. While guidance suggests there is up to a 30% chance for gale
force gusts, especially Wednesday, the wind direction is unfavorable
for getting gales during the cold season, so have kept the forecast
below gale criteria for now.
&&
.TIDES/COASTAL FLOODING...
As a result of the Full Moon on December 4th, some minor tidal
flooding will be possible during the daytime high tides through
Sunday. This is primarily for the NJ and DE coasts and lower
Delaware Bay. 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.
However, latest guidance keeps water levels below advisory
thresholds.
No tidal flooding is expected elsewhere.
&&
.CLIMATE...
Very cold 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.
SITE RECORD/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...Cooper/Johnson
NEAR TERM...DeSilva
SHORT TERM...Cooper/Johnson
LONG TERM...Cooper/Johnson
AVIATION...Cooper/DeSilva/Johnson
MARINE...DeSilva/Johnson
TIDES/COASTAL FLOODING...
CLIMATE...
Office: PBZ
FXUS61 KPBZ 061209
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
709 AM EST Sat Dec 6 2025
.SYNOPSIS...
Periodic light snow chances and below-normal temperatures
continue through the weekend. A dry start to next week turns
active with rain and snow chances returning mid to late week.
&&
.NEAR TERM /THROUGH TONIGHT/...
KEY MESSAGES:
- Light snow showers possible mainly north and east of
Pittsburgh; little to no accumulations expected
- Below seasonal temperatures continue
---------------------------------------------------------------
A weak mid-level shortwave traverses the Ohio Valley today,
bringing low chances for light snow showers to areas generally
north of Pittsburgh and in the ridges of southwest PA.
Occasional flurries may be possible elsewhere. Little to no
accumulations are expected as the NBM continues to suggest a
less than 20% chance for even a tenth of an inch of new
snowfall anywhere in the local area.
Temperatures continue to trend below seasonal normals, with
highs in the mid 30s and lows in the mid to upper 20s.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
KEY MESSAGES:
- Another disturbance brings minor snowfall accumulations to
areas north of Pittsburgh and in the ridges; a rain/snow mix
with little accumulations expected elsewhere
- Dry weather and below seasonal temperatures prevail Sunday
night through Monday night under building high pressure
----------------------------------------------------------------
Another passing shortwave brings higher chances for a wintry
mix to the entire area on Sunday. Precipitation is expected to
start as snow (possibly a rain/snow mix in the Mon Valley)
Sunday morning before transitioning to a rain/snow mix across
the lowlands south of I-80 by late morning and afternoon.
Overall accumulations with the Sunday system are still
anticipated to be light, with measurable snowfall appearing most
likely north of I-80 and in the ridges. NBM snowfall probabilities
are rather pessimistic, suggesting a 40-60 percent chance for a
tenth of an inch north of Pittsburgh and in the ridges, but a
20 percent chance or less for an inch. Meanwhile, the event is
just now beginning to fall within range of the HREF, which is
suggesting higher probabilities (anywhere from 40 to 80 percent)
for an inch of accumulation north of Pittsburgh (and especially
along and north of I-80), but significantly lower probabilities
of around 10-20% for 2 inches in the same areas. Probabilities
are also generally lower in the ridges, for example a 30 to 50
percent chance for an inch of accumulation in the Laurels.
However, the latest HREF only runs through 7pm Sunday, so it's
possible these probabilities increase in future runs as snow
showers are forecast to linger in the ridges through evening.
A cold front late Sunday brings a reinforcing shot of cold air,
leading to low temperatures dropping back into the teens north
of Pittsburgh and low 20s elsewhere Sunday night. Dry weather
and below-seasonal temperatures then continue Monday and Monday
night under the influence of building high pressure.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
KEY MESSAGES:
- Below normal temperatures continue through the long term.
- Additional rounds of potential winter weather with a series
of passing disturbances mid and late week.
-------------------------------------------------------------------
Another disturbance moving through the area Tuesday into
Wednesday will feature a strong and progressive low pressure
system track in from the northwest as a trough over the east
continues to filter colder air and precip chances into the
region. The surface low associated with this system is expected
to lift into southern Ontario as it approaches the lower Great
Lakes, resulting in warm advection setting up across the area
on Wednesday which will likely force a changeover to rainfall,
(thus limiting snowfall accumulation potential) for areas south
of I-80. The latest NBM shows a 30-50 percent chance for an
inch of snowfall accumulation in the northeastern corner of the
CWA, generally north of I-80 and east of I-79. Lower chances
for an inch of accumulation exist in the ridges, with a 10-30
percent chance from the Laurels down into Preston and Tucker
Counties in northern WV.
Thursday serves as a potential transition day between the
departing mid-week system and an approaching late week system,
with a period of dry weather sneaking in during the day (save
for the ridges which may see weak upslope-forced showers
persisting). Uncertainty in timing of the departure of the mid-
week system (Wednesday vs. Thursday) and arrival of the late
week system (Thursday vs. Friday) is forcing non-zero PoPs in
the forecast on Thursday, but there should be at least some
window in between the two systems during which we see dry
weather and below-seasonal temperatures.
The late week system will be the more interesting one to watch
as it dives southeastward from the Canadian Rockies into the
Upper Midwest hot on the heels of the mid-week system and
traverses the Ohio Valley in the Thursday/Friday timeframe.
There is still a fair amount of spread regarding the track and
potency of this disturbance, but there are some global models
and ensemble members that depict a scenario in which the low
moves either through or south of the local area, which would
increase our chances in seeing impactful winter weather. This
will be a system to keep an eye on as we head into next week.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
A low MVFR deck of stratus still sits across the region this
morning. VFR cigs are observed on the W/NW side of this deck,
and eventual erosion/eastward movement of this is expected to
slowly bring VFR back to most area ports through the morning
hours. It's tough to pinpoint the back edge of it on satellite
with upper level clouds obstructing, but observations suggest
it's along a line roughly from ZZV to BVI as of 12z.
Erosion of the stratus deck combined with increased mixing/lift
this morning ahead of an incoming shortwave should result in
improvements. However, any VFR conditions are likely to be
short-lived as the afternoon passage of the shortwave re-
introduces an MVFR stratocu deck and lower probability light
snow showers (FKL/DUJ having greatest likelihood for visibility
impacts due to snow, so have introduced a TEMPO group for
-SHSN there).
Outlook...
The overall weather pattern through late next week strongly
favors shortwave movement within upper troughing that occurs
almost every other day. Each system will feature varying degrees
of precipitation chances (type mainly snow, save for short
periods of rain at southern terminals), intensities, and either
the continuation of or reintroduction to MVFR-IFR restrictions.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...Shallenberger
NEAR TERM...Cermak
SHORT TERM...Cermak
LONG TERM...Cermak
AVIATION...MLB/AK
