State College, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

880
FXUS61 KCTP 201906
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
306 PM EDT Sun Jul 20 2025

.SYNOPSIS...
* A cold front pushes through the region late this afternoon and
  evening accompanied by a few showers and possibly a
  thunderstorm across the Northeast third of the state.
* A multi-day, rain-free dry spell with comfortably low humidity
  and refreshingly cooler temperatures will follow for Monday
  and Tuesday.
* Hot and humid conditions return by late week with moderate to
  major Heatrisk Thursday into Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
SFC cold front stretched from near KELm to KFKL and KYNG at 18Z
with numerous small scale showers speckled across much of the
CWA.

This is the second, back to back cold front that was topped by
unfavorable (for deep convection) quadrants of the upper level
jet passing over the CWA. The first occurred this past
Thursday, where basically no showers at all occurred as mid
level temps around +11C capped off the otherwise robust CAPE.
This afternoon, temps aloft are notably cooler and in the +6-9C
range allowing thin CAPE to form tall showers, with the only
deep convection/lightning so far occurring over our far NE
zones, where the left exit region of the jet was enhancing
MESO-B scale lift and better llvl theta-E convergence and deep
layer shear was present.

Broadly diffluent llvl westerly flow across the southern third
of PA will limit the depth and areal coverage of the showers
ahead of the cold front.

Looking ahead to tonight, we`ll have the 1st of 3 comfortably
cool nights (the first multi-day string quite some time) across
CPA. Fcst min temps are 10-15F lower than last night (daybreak
Sunday) in the low 50s across the NW Alleghenies. Some low
clouds and areas of fog/low upslope stratus may develop over
the western high terrain into early Monday morning. Lows in the
mid to upper 60s will still be sticky/muggy in the Lower Susq
Valley, but relief is on the way!

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Monday will kick off a 2-3 day period of refreshingly cooler and
less humid conditions as a 1020+ mb sfc high pressure area
builds SE from the Upper Great Lakes.

This weather feature will deliver mostly sunny and rain-free
days with low humidity followed by comfortably cool nights - good
for campfires and sleeping with the windows open!

We were keen to manually adjust Td lower Monday afternoon based
on pattern recognition and dry air mixing signal in the
sounding profiles with deep dry air above the base of the weak
subsidence inversion located above 4 kft AGL.

Highs on Monday will be about 3-8 degrees cooler vs. today, but
the most noticeable/refreshing change will be to overnight
temps which should dip into the 50s in most locations Monday
night with even some mid to upper 40s in the northern tier!
Under favorable radiational conditions, the cooler min temps
should trigger the 20-25F water-air threshold and allow fog to
form in some of the river and stream valleys.

Temps should reach a nadir Monday night with a neutral/flat
trend on Tuesday before printing a higher low Tuesday night.
This will signal an impending return to sweltering heat poised
to return for late week into the weekend.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Add 5-10 degrees to max temps and 10+ to dewpoints by Wednesday
as PWAT values via the GEFS climb back to around 1.25 inches
(still within the +/- 1 sigma range and not the muggy 1.5 to 2
inch values we recently experienced).

So, trending warmer and more humid into midweek, but still high
confidence in no precip as 6 hour GEFS probs for 0.05 of an
inch of rain remain below 10 percent into Thursday afternoon.

Model and ensemble data show a building heat dome/590+dm 500mb
ridge expanding over the area for late week into the weekend.
This will translate into a return of hot/humid late July
sensible wx conditions. Heatrisk ramps up to moderate to major
with heat index values fcst to approach or reach the century
mark. This will be something to monitor in the coming days.

Some isolated/scattered airmass or terrain induced convection
is possible beneath the upper level ridge Thu afteroon/Fri, but
higher POPs lean toward next weekend tied to the arrival of the
next frontal system/upper level trough.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
Scattered showers (and a few thunderstorms east of a KIPT to SEG
and KMUI line) will continue into early this evening ahead of
a cold front that was pushing through NW PA this mid afternoon
hour.

If any briefly heavy showers thunderstorms move directly over
any airfields, brief reductions in visibility and gusty winds
will be possible. Outside of any thunderstorms, west- northwest
winds will ramp up a bit further and gust to 20-25 knots through
dusk before decreasing back to 10 KTS or less overnight.

Rain chances will come to an end after 00Z as the cold front
exits the area and northwesterly flow will lead to clearing
skies east of the Allegheny Front. Some low clouds may develop
to the west, with BFD and JST being most likely to see MVFR
restrictions (40-60% chance).

Outlook...

Mon-Wed...VFR with mainly dry conditions.

Thu...Mainly dry. Perhaps a shower or storm across the
west late.

Friday...Mainly dry and hot, with isolated to scattered
TSRA and brief restrictions possible Friday afternoon/evening.

&&

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

&&

$$

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