546
FXUS61 KCTP 050903
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
503 AM EDT Fri Sep 5 2025

.SYNOPSIS...
* A cold front will move through late tonight and Saturday with
  several rounds of showers and a chance of a gusty thunderstorm
  across the eastern half of the state.
* High pressure then controls the wx for a week.
* After a slight cooling Sunday and Monday, the temperatures
  warm slowly each day next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Sfc cold front has come to a screeching halt and extends from
near KIPT to KUNV and KIDI.

Clearing across the NW half of the CWA combined with cooler
temps and near calm air led to the formation of widespread dense
fog there late last evening and the fog hasn`t improved one bit
as of early today. In fact, breaks in the layered cloud cover
south of the frontal boundary has led to patchy dense fog,
especially across portions of the Lower Susq Valley.

Temp/Dpt spreads have greatly narrowed to 1 deg F or less at
most sites, even south of the front, and we may need to expand
the Dense Fog Advisory for several hours.

Sfc and upper flow backing to the south and southwest
respectively will cause this initial front to wash our across
Central PA and partly to mostly sunny skies and dry conditions
(after the fog dissipates) will cause temps to rapidly climb
and reach afternoon maxes 5 to 8 deg F above normal at most
locations.

It will still be rather humid this afternoon across the
southeastern zones where sfc dewpoints will hover in the 60-65F
range.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
After a relatively tranquil evening, a stronger cold front
(compared to the current, dissipating one over Central PA)
will push slowly east through the Commonwealth and bring a
renewed, high probability for showers and thunderstorms. The
primary threat for a strong TSRA on Saturday will be across the
Susq Valley, based on the expected timing of the cfropa there
Saturday afternoon. SPC has the Western Poconos and Lower Susq
Valley covered with a MRGL risk for SVR TSRA. Based on the
deepening/strengthening shear on Saturday, the current SPC MRGL
risk could be raised to a SLGT - especially if there is a fair
amount of sunshine for a few to several hours.

Pertinent part of the previous Disc...

There remains some uncertainty regarding how much instability
will be in place ahead of the front (and the timing of the
cfropa itself with the GFS being the quickest and driest for
much of Central PA where it shows only a few hundredths of an
inch of QPF after 14-15Z Saturday), but scattered strong to
severe thunderstorms seem like a good bet. As is typical with
these systems, the best chance for severe will likely be in
southeast PA and an SPC Marginal Risk is probable for Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
For the long term period, a prevailing upper trough across the
eastern US will remain in place, perhaps lifting a bit by the
middle of next week.

After the cold front sweeps through, another fall-like pattern
will settle in for the second half of the weekend and into next
week. The airmass moving overhead will be the coolest of the
season so far. Highs in the 60s and 70s will pair with lows in
the 30s to 50s. Frost or freeze conditions seem like a good bet
for the typical cool spots in northwest PA early next week along
with river valley fog. Abundant sunshine and dry conditions are
favored, with increasing moisture and chances for rain toward
the middle to end of the week.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
Ample low-level moisture will remain in place allowing for
widespread MVFR-to- IFR conditions in fog across central
Pennsylvania. Highest confidence remains at BFD/JST/IPT with
increasing confidence at MDT/LNS. UNV/AOO remain the most
uncertain with regards to low cloud/fog potential overnight;
however, fairly good signals still exist for at least MVFR
restrictions closer to sunrise based on a combination of
HREF/RAP model guidance.

Clearing will be relatively quick after 12Z Friday with
southwesterly flow; however, IPT will likely hold onto lower
ceilings/visibilities through ~14Z Friday. Clearing skies are
projected by the bulk of model guidance allowing for widespread
VFR conditions through 00Z. Scattered-to-broken high-level
clouds are progged by a combination of HREF/GLAMP/RAP model
guidance, thus have kept cloud cover in with moderate
confidence.

Outlook...

Sat...Chance of SHRA w/ TSRA possible, especially SE.

Sun-Mon...Clearing with VFR conditions. Breezy.

Tue-Wed...Clear.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 10 AM EDT this morning for PAZ004>006-
010>012-017-018-024-037-041.

&&

$$

SYNOPSIS...Lambert/Dangelo
NEAR TERM...Lambert/Dangelo
SHORT TERM...Lambert/Bowen
LONG TERM...Banghoff/Bowen
AVIATION...Gartner/NPB