499
FXUS61 KCTP 142326
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
726 PM EDT Mon Sep 14 2026

.WHAT HAS CHANGED...
*Minor edits to lower dewpoints and bump up wind today
*Lower minimum temps tonight

&&

.KEY MESSAGES...
1) Noticeably cooler/pleasant and rain-free start to the week
2) Warm/humid conditions return mid to late week with best odds
for rain Thursday

&&

.DISCUSSION...
KEY MESSAGE 1: Noticeably cooler/pleasant and rain-free start to
the week

Refreshing airmass behind cold front today with dewpoints in the
40s and 50s. Fair weather cu across much of the region with max
coverage near the Great Lakes. Max temps will be 10 to 15
degrees lower/cooler vs. Sunday ranging from the mid 60s in the
northern tier mtns to the mid 70s in the southern valleys along
the MD line.

Strong radiational cooling pattern tonight into early Tuesday
morning with very low pwats beneath area of high pressure
migrating over CPA. Min temps into the upper 30s are definitely
in play in the usual northern tier cold spots with 40-50F lows
anticipated elsewhere (4-8F below climo). This setup favors
valley fog formation with localized visibility restrictions
below 1 mile.

Wide 25-35 degree diurnal range fcst Tuesday with another
pleasant afternoon with max temps in the upper 60s to mid 70s.


KEY MESSAGE 2: Warm/humid conditions return mid to late week
with best odds for rain Thursday

Return SSW flow on the back side of the high pressure system
will pump the dewpoints and moisture/humidity back up from mid
to late week. Best rain/QPF signal at this time is on Thursday
9/17 as a weak front sinks southward from the eastern Great
Lakes. If the front can push south of the MD line, most of
Friday could be dry. Precip odds then steadily increase over the
weekend ahead of next frontal system progression from the Great
Lakes. Large scale upper level ridging should support a mid to
late week warming trend with the largest hi/lo departure from
climo Wed-Thu.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Few high clouds remain over the airspace as the sun sets. Clear
skies are anticipated tonight with dry air near the surface
making for a calm clear night.

Despite lack of appreciable cloud cover leading to robust
radiational cooling tonight, dewpoints mostly in the low to mid
40s statewide should limit fog coverage tonight. Latest
thinking is any that forms will be contained to the valleys
without any terminal impacts. Current HREF probabilities have
most areas 20% chance at most for visibility impacts so
confidence isn`t high enough for any fog FM groups

With the high pressure system moving to our east tomorrow, winds
will turn more southerly. Gusts greater than 15kts look most
likely at BFD with an approaching front and upper level jet from
the north inducing more convective mixing.


Outlook...

Tue-Wed...AM fog possible, otherwise mainly VFR.

Thu-Sat...Increasing SHRA/TSRA chances, mainly on Thu,
restrictions possible.

&&

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

&&

$$

WHAT HAS CHANGED...Colbert
KEY MESSAGES...Steinbugl/Colbert
DISCUSSION...Steinbugl/Colbert
AVIATION...Bowen/Lambrech