486
FXUS61 KCTP 221346
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
946 AM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...
* Added scattered showers to the SE half of the CWA through the
  rest of this morning

&&

.KEY MESSAGES...
1) Mainly dry, tranquil and cooler weather pattern expected
into the last weekend of July.

&&

.DISCUSSION...
KEY MESSAGE 1: Mainly dry, tranquil and cooler weather pattern
expected into the last weekend of July.

A narrow, Northeast to Southwest band of slightly cooler mid
level temperatures (+4 to +7C) was moving over the Allegheny
Front late this morning, leading to scattered/brief showers
capable of just wetting the ground with 0.01-0.02". This mid
level feature will be over far SE PA and the BWI/DCA area by
early this afternoon.

As the quick moving showers move into an environmnet of SFC
Based CAPE between 1200-1700 J/KG, they will grow and be capable
of bringing locally around 0.05" in the greater York, Harrisburg
and Lancaster areas between about 15-16Z.

Previous Disc...

Cool cyclonic/WNW flow aloft will trigger light rain shower
activity today downwind of Lake Erie over the Allegheny
Plateau. Hires guidance shows low clouds/stratocu slow to erode
this morning over the western high terrain. Exiting cold front
could trigger an isolated PM t-storm over the far southeast part
of the CWA, but precip odds are less than 20%. SPC has shifted
the level 1/5 MRGL risk out of Lancaster County to the I95
corridor. Max temps in the mid 60s to mid 70s over the
Alleghenies are 5 to 15 degrees below the historical average
for late July. The relatively cool daytime temps today will be
enhanced by a noticeable WNW breeze gusting 20-25 mph. Mainly
clear skies expected tonight with below climo to chilly min
temps for this time of year fcst in the 40-60F range from NW to
SE. Areas of valley fog are expected late tonight into early
Thursday morning.

The cooler/less humid airmass will usher in a dry spell into the
last weekend of July with high pressure in control. Upper trough
carving out over the eastern Great Lakes into the Northeast US
will bring rain chances back into the forecast Sunday into next
week.

&&

.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
Updated the TAFS of mid morning. Cold front still yet to move
south and east of the area, thus more clouds and some showers
into late morning.

More information below.

Convection has largely ended across the area with only a few
light showers and lingering low clouds remaining. HREF/GLAMP
guidance continues to outline lower ceilings and visibilities
most likely across the western terminals (BFD/JST) so have
continued to outline this potential in the updated forecast
package. Elsewhere, guidance paints a more optimistic picture
for flying conditions compared to the 18Z TAF package, likely
due precipitation not being as widespread as originally
forecast. Some pockets of MVFR/IFR will be possible at UNV/IPT
as well for a few hours. Gradual improvement of the western
airfields is expected after sunrise, with widespread VFR
conditions expected to prevail in the 14-16Z Wednesday timeframe
with high (~70-80%) confidence. These conditions are likely
(~80-90%) confidence to continue after prevailing for the next
24 hours.

Outlook...

Thu-Fri...Some potential for valley fog across NW PA Friday
morning; otherwise, VFR conditions expected.

Sat...Generally VFR conditions with low-end (< 20%) chance of an
afternoon shower/storm across SW PA.

Sun...Increasing chances of PM showers/storms, with some
restrictions possible.

&&

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

&&

$$

WHAT HAS CHANGED...Lambert/Steinbugl
KEY MESSAGES...Lambert/Steinbugl
DISCUSSION...Lambert/Steinbugl
AVIATION...Martin/Beaty/Bowen