Altoona, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

926
FXUS61 KCTP 240034
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
734 PM EST Tue Dec 23 2025

.SYNOPSIS...
* Partial clearing and turning windy tonight in the wake of a
  weak cold front
* Potential for a light wintry mix - mainly over parts of
  Central Mtns and Laurel Highlands early Christmas morning,
  then a higher probability for a period of snow followed by a
  significant wintry mix Friday- Friday night
* Mild trend this weekend followed by sharply colder conditions
  and strong winds to start next week

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A surge of warm air advection from the west/southwest at low to
mid levels this afternoon will ascend over the shallow cold air
locked in the Central Valleys and Susquehanna Region for the
rest of today. This will lead to plenty of low, stratus clouds
and some areas of light rain/drizzle and ridge shrouding fog.
The fairly weak low level p-gradient and lack of strong
subsidence aloft is making it difficult for the warmer air to
mix down/scour out the cooler/dense air trapped in the Central
Valleys attm.

Temps will continue to slowly climb into early tonight, prior to
a cold frontal passage and therefore, high temps in many places
will probably be achieved tonight.

Conditions dry out this evening (West) and overnight across the
east with WNW winds increasing tonight into early Wednesday
morning in the wake of the aforementioned front.

Increased deep-layer subsidence beneath the thermally indirect,
right exit region of a 150 kt 300 mb jet will combine with a
tightening llvl pressure gradient/sfc pres rises (in response
to deepening low offshore New England and vertical mixing up to
around 3 KFT AGL) to bring 30-40 mph wind gusts to the area
late tonight/wed morning. Model data shows a wind gust max
approaching advisory criteria centered over the Poconos/Endless
Mtns including Sullivan County.

For now, KPHI has a Wind Advisory for the southern Pocono
Plateau, while KCTP and KBGM have opted to hold off on an
Advisory for now - capping off peak gusts in the mid to upper
30s (KTS).

Will have to watch this closely, as we do have the v-component
of the 850 mb NW wind on the GEFS at an impressive -3 to -4
sigma.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
High pressure migrates over CPA Wednesday afternoon decreasing,
then ending the gusty winds and bringing a dry day for holiday
travel.

Mid and high clouds increase/thicken up fairly quickly wed
afternoon/(Christmas Eve) in this very progressive pattern as a
weak shortwave dives southeast from the Midwest toward the
Central Appalachians.

Model data indicates some light (a few to several hundredths of
an inch) mixed precip could reach the forecast area in the
06-12Z Thu timeframe with the best odds over the southwestern
quadrant of the CWA.

In contrast to the current, departing storm where wet bulb maxes
were generally below zero C - supporting the bulk of the precip
falling as snow, the early Christmas day weather maker will be
working with Tws anywhere from +2-5 C throughout a deep layer
just above the surface. This will almost guarantee the bulk of
the very light precip falling as -FZRA.

The weather looks largely benign for the rest of Christmas Day
with cloudy skies and max temps +5-10F above the historical
average. High pressure ridge drifts over CPA Thursday night and
channels down the east side of the Appalachians, setting the
stage for an overrunning wintry mix event for Friday.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Model and ensemble data show a solid consensus precip signal
for Friday as 0.25-0.50" mean QPF encounters/overruns a
retreating cold sector airmass. Confidence is increasing in a
significant wintry mix event Friday-Friday night, likely
starting out as a few to several hour period of light to
moderate snow. NBM prob of more than 4 inches of snow/sleet
exceeds 40% over the eastern half of the CWA, where a fairly
steep/stationary frontal boundary (being fed by a slightly
anomalous llvl u-comp of the 925 mb wind) will likely lead to
some enhanced FGEN forcing and NW/SE bands of MDT snow within
the overall precip shield. Temps will be 5 to 15F colder on
Friday (vs. Thursday/Christmas Day).

Temperatures are projected to trend milder over the weekend -
peaking on Sunday 5-15 degrees above the historical average in
the 40-50F range.

An arctic blast is possible by Monday following the passage of
a strong cold front. There is also a signal for high winds
behind the front along with lake effect snow. Fcst highs for
Monday are 15 to 30 degrees colder than Sunday with wind chills
in the +/- single digits.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Low ceilings persist across all airfields outside of the Lower
Susquehanna Valley sites (MDT/LNS), where HREF/RAP/GLAMP model
guidance outline higher probabilities in low-end MFVR ceilings
occurring for a two-to-three hour window stationed between
00Z-05Z Wednesday. Thus, have added mentions in the near-term
before improving by 06Z Wednesday. Elsewhere, gradual
improvement in ceilings overnight is progged by a combination of
RAP/GLAMP model guidance, especially in the 06Z-12Z Wednesday
timeframe. There is high (~70-80%) confidence on improving
conditions with main uncertainty coming with respect to timing
of the improvement. By 12Z Wednesday, all model guidance points
towards widespread VFR conditions outside of BFD/JST, where
GLAMP/RAP model guidance outlines restrictions lifting after 15Z
Wednesday with moderate-to-high (60-80%) confidence.

Recent PIREPs near HMZ/UNV have outlined the presence of LLWS
across central Pennsylvania, thus have continued mentions in the
00Z TAF package with high (~90%) confidence through 06Z. LLWS
will be on a decreasing trend overnight, with LLWS concerns
largely expected to diminish by 12Z Wednesday. Gusty winds are
expected overnight with 20-30kt gusts expected across much of
the forecast area, with locally higher gusts 30-35kt across the
higher elevations surrounding JST/AOO. Winds will gradually
diminish after 12Z Wednesday as surface low pressure drifts
further east of the area and allows for less of a pressure
gradient driving these gusty winds.

Outlook...

Thu...Scattered rain showers, some FZRA possible mainly central
and SW PA. Restrictions possible.

Fri-Sat AM...Widespread -SN developing, possibly changing to
sleet or a brief period of -FZRA late Friday. Restrictions
probable.

Sat PM-Sun...Rain with -FZRA possible across higher elevations.
Restrictions possible.

&&

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

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert
SHORT TERM...Lambert/Steinbugl
LONG TERM...Lambert/Steinbugl
AVIATION...NPB