421
FXUS61 KCTP 250020
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
820 PM EDT Sun Aug 24 2025

.SYNOPSIS...
* Scattered showers and a few thunderstorms through the evening;
  last warm and humid day for a while
* Fall-like pattern poised to arrive this week with cooler than
  average temperatures and refreshing breeze from the northwest
* Lake effect rain showers downwind of Lake Erie early this
  week; otherwise a multi-day dry stretch to close out August

&&

.NEAR TERM /UNTIL 8 AM MONDAY MORNING/...
Isolated/sparse convective development so far this afternoon
has been within SSW/NNE oriented theta-e ridge and instability
axis over the central mtns (near I-99/US-220) on the western
edge of slowly dissipating low cloud gradient. Max pwat axis
around 1.5 inches has shifted into eastern PA. Hires model
output continues to key on a narrow N-S corridor of showers and
storms developing through the evening setting up closer to US-15
corridor most likely along a prefrontal trough/convergence axis.
Given the overall marginal convective environment, limited
forcing for ascent, and largely progressive cell motions, the
severe storm/excessive rain risk should remain relatively
sporadic/limited.

We are not anticipating much if any shower/t-storm activity
over the western portion of the area -- with plenty of dry air
aloft mixing dewpoints into the mid 50s across the Allegheny
Mtns/Laurel Highlands. Showers could linger into late tonight
particularly over the eastern/northeastern portion of the CWA
as the primary cold front sweeps eastward across the Commonwealth.

&&

.SHORT TERM /8 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
A series of shortwave troughs embedded within a large upper
trough carving out over the Eastern U.S. will bring a taste of
Fall to central PA to close out the month of August. Relatively
cool cyclonic flow will bring scattered rain showers/storms
downwind of Lake Erie into the NW Alleghenies early this week.
Elsewhere, we expect a stretch of dry wx to begin Monday along
with below normal temps and a refreshing breeze from the NW.
Max/min temps trend lower into midweek with lows Tuesday night
in the 40-55F range. Overnight clearing with light winds could
result in locally dense fog in the valleys.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Reinforcing upper level support will maintain Fall-like cold
sector over the Great Lakes, Northeast, and Mid Atlantic states
through late week. The amplified pattern does show some signs of
slowly weakening by the end of August. Temperatures are
forecast to remain below the historical average heading into
September with drier than normal dewpoints supporting
comfortable days and relatively cool nights with perhaps some
overnight low temps in the upper 30s in the northern tier.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
Low VFR cigs dominate into tonight with some local restrictions
possible in brief showers/t-storms. A few area could break out
into localized fog development overnight, but overall confidence
is low in fog development. IPT currently is the highest
confidence of visibility restrictions due to fog. Transition
toward a NW flow pattern will perpetuate sct- bkn mainly VFR
cigs and increasing wind from 280-320 degrees 15-25kts behind
cold frontal passage by Monday afternoon.

Outlook...

Mon-Tue...Patchy fog possible starting Monday night into
Tuesday morning.

Wed-Thu...No sig wx

Fri...Iso showers NW

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...Steinbugl/Bowen