Lancaster, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

274
FXUS61 KCTP 060404
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1104 PM EST Fri Dec 5 2025

.SYNOPSIS...
* Light snow accumulation likely over the western and central
  Alleghenies later Sat and again 24 hrs later
* Reinforcing shots of cold weather and clippers provide
  additional opportunities for snow throughout the next 7+ days
  for the northwestern half of PA.

&&

.NEAR TERM /UNTIL 8 AM SATURDAY MORNING/...
CLouds have done the job of keeping temps up from last night.
But, they also are hanging down low enough to touch the highest
ridge tops where temps are (well) below freezing. We have heard
reports of FZDZ in the Laurels just to the east of Somerset Co,
and we`ve been carrying mentions of patchy FZDZ for a while.
We`ve tried to highlight the not-widespread threat of icy
patches via an SPS (special wx statement). We will keep an eye
on developments thru the night, but it is not expected to get
worse than patchy icy spots.

&&

.SHORT TERM /8 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Have tried to bring more continuity to the PoPs for Sat and Sat
night. Expect -SHSN over the wrn mtns as a very weak upper short
wave trough passes through. Some breaks in the clouds are
possible Sat and again Sun, but many layers of clouds are
expected to make it tough to find them. Some clearing is
possible for the SE half Sat night.

Prev...
Some fleeting sunshine possible Saturday, but don`t bank on it
in most places, as the exit of the aforementioned widespread
stratus deck (resulting from development of a mean swrly llvl
flow) is quickly replaced by a dual layer of higher based
stratocu and thick layer of mid and high clouds.

The passage of a weak sfc trough will add a southwesterly breeze
on Saturday, helping to push max temps closer to early December
climo with highs +5-10F warmer day/day in most locations.

Highs Sat afternoon will range from 30-35 across the northern
mtns to the low 40s in the southern valleys.

Lake effect snow trajectories marginally improve by Saturday
night over the NW mtns (generally northern Warren and Mckean
Ctys) before lowering inversion heights and backing low level
winds keep light snow accums mainly confined to the I90
corridor.

Split/northern stream trough swings through on Sunday and likely
brings some light (lake/terrain enhanced) snow primarily to the
western and northern Alleghenies. NBM snow accum favors sub-
advisory level accumulation for most areas, with the best odds
for 2-3" across the NW mtns along and north of US-6.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
A cold but quiet start to next week will be followed by a
reinforcing cold weather pattern as we see the exit to the east
of the strong and persistent SWrly Subtropical Jet from the Baja
area to the Carolina Coast.

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 migrating through and reinforcing the Eastern
U.S. trough will bring at least 2-3 opportunities for snow (and
possibly a little mixed precip across the south).

The next, best chance for wintry precip area-wide is
Wednesday/Wednesday night, as a vigorous clipper drops southeast
across the region. Model consensus points toward low-end
advisory category snow (3-4 inches) possible across the nrn and
western mtns with an inch or so of accum in the central Ridge
and Valley region associated with the several hour period of
warm advection snow in advance of the upper shortwave.

The second noteworthy precip event for next week will come
Friday as a similar shortwave (but with a much more southern
track) spreads some snow over primarily southern PA as a
northerly llvl flow with 850 mb temps in the -8 to -12C range
will ensure deep cold air in place for all snow.

Confidence remains high in below normal temperatures; Monday
night could be another frigid period with lows -5F to +15F by
daybreak Tuesday.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Not much change for the 00Z TAF set.

There could be isolated tiny snowflakes at times overnight,
some indication of this on the radar returns on the MD/PA
border as of 5 PM. MVFR to IFR CIGS across the entire area
as of 5 PM as well, not seeing much change in conditions
overnight. CIGS will trend to lower with time, before
improving later on Sat.

See earlier information below on the potential for very light
freezing drizzle with the lower CIGS over the higher terrain.

Earlier information below.

Widespread MVFR to low end VFR stratus covers all of the
Central PA the mid afternoon hour. Ceilings will lower to
IFR across most of central PA during the evening and overnight.

Once IFR ceilings develop, they will likely persist at BFD,
JST, and LNS through 12Z Sat. The other sites may see ceilings
rise to MVFR before sunrise Sat.

Some patchy light freezing drizzle is possible late today
through early Sat where cloud bases lower to within 500 feet or
so of the ground (which will occur mainly on the ridge tops).

Outlook...
Sat...Restrictions possible, chance of snow showers in the NW

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...Snow/restrictions possible mostly in the second half of
the day

&&

.CLIMATE...
A couple of record lows were set this morning (12/5/2025).

Location     | Actual low (thru 5 PM) | Record (YEAR)
------------   ----------------------   --------------
Harrisburg   |         21             |   12 (1926)
Williamsport |         10             |    8 (1926)
Bradford     |         -8 **          |    0 (2007) **
Altoona      |         12 **          |   13 (1966) **
Johnstown    |          8             |    3 (1966)

                 ** record broken

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Lambert/Dangelo
NEAR TERM...Dangelo
SHORT TERM...Lambert/Dangelo
LONG TERM...Lambert/Steinbugl/Banghoff
AVIATION...Lambert/Martin/Bauco
CLIMATE...Dangelo/NPB