799
FXUS61 KCTP 221702
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
102 PM EDT Wed Jul 22 2026

.WHAT HAS CHANGED...
* No significant changes with this update.

&&

.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.

The airmass is drying out across CPA with sfc dewpoints
gradually falling by several degrees from earlier this morning.
16Z TDs range from the low 50s across the NW Mtns to the low 60s
near the I-99/RT 220 corridor and mid to upper 60s in the far SE
part of the CWA.

a brief period of clearing skies followed closely by 2-3 deg C
of cooling (centered around 700 mb) have helped to boost the
areal coverage and depth of the cu field across the region with
the greatest sky coverage found across the Alleghenies where
even some narrow bands of LER showers were forming over and
streaming SE of Lake Erie as a result of the water to 850 mb
delta T of around 16 deg C.

Expect some brief showers across the NW Mtns this afternoon.
However, a few unlucky locations that get stuck under one of
these 2-3NM wide bands of rain could see up to one tenth of an
inch of rain.

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 /18Z WEDNESDAY THROUGH MONDAY/...
High pressure over the central states will slowly build
eastward into Pennsylvania over the next few days.

This afternoon will feature a gusty northwest wind, as a cold
front drops south and east of PA. Low CIGS will prevail over
the mtns for a few more hours.

Expect a bit of a breeze overnight, so not much chance of fog.

VFR conditions should prevail into at least the first part of
Saturday, before the chances of showers and storms increase
later in the weekend.

Outlook...

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 western sections of central PA.

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

Mon...Still a chance showers and storms.

&&

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

&&

$$

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