176
FXUS61 KCTP 311117
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
717 AM EDT Sun Aug 31 2025

.SYNOPSIS...
* Dry weather is expected to continue through the middle of next
  week, featuring cool nights, and warm comfortable afternoons
* Frost possible again Sunday morning in northern PA.
* Next chance for rain comes Thursday and Friday with a cold
  front.

&&

.NEAR TERM /THROUGH TONIGHT/...
Fog forming in the river/stream valleys. Expect it to last into
the mid- morning where it is most-dense. A couple of
backyard/meso obs are into the 30s, now, mainly right where the
frost advy is (McKean Co). So, temps are on track.

Expansive high pressure centered over the Great Lakes is
dominating our weather pattern again today, and will for the
next 3 days as it slowly migrates east. A patch of high, thin
cirrus over nrn PA will drop down across Central PA today, and
some diurnal cu are expected (mainly NE). But, it will be
another dry and mild day with wording of mostly sunny excellent
to describe the sky. Max temps today should be 6-10F warmer in
the NW vs Saturday, and 2-3F warmer in the SE. That puts us very
nearly normal on highs across the entire CWA.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
More good news for those wanting to be outdoors, and if you
like saving money on your heating/cooling bills. The high
pressure centered just to our N will continue to slide E.
Expect only fair-weather clouds for the end of the Labor Day
weekend. Some fog is again possible in the cooler valleys of the
N tonight and Monday night. There should be more cu on Monday
vs the last few days. Middle of the road NBM temps are looking
good. Might have to add more cu to Monday aftn fcst based on
moisture profiles from deterministic model moisture plots. Did
not make any notable adjustments at this point.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
3 AM Update...
Biggest concern with the long range is the probability of precip
for the Thursday-Thursday Night period when a cold front is
slated to pass through. NBM guidance has a solid grasp of the
period of highest probability being Thurs and Thurs night.
Deterministic ECMWF is the outlier at this point by developing a
wave along the front as it works thru Central PA, delaying FROPA
and prolonging higher rain chances versus most other models and
ensembles. Next weekend may not be entirely dry, but the front
should be to our east before Saturday and our chcs for rain drop
to below 20 pct.

Prev...
The upper-level, synoptic-scale configuration looks to feature
a transition towards an amplified pattern, with a building
western North American ridge axis, a deepening Great Lakes and
Midwestern trough axis, and a western Atlantic ridge. Given
consistency of our ensemble prediction systems in showing this
pattern, confidence is relatively high.

At the beginning of the period (Tuesday and Wednesday), with a
deep layer of dry air still in place and continued moderation of
daytime highs over time, minimum afternoon RH values will dip.
By Wednesday, we may also see increasing SW winds in the
boundary layer, as surface high pressure starts to push eastward
off the coast. In fact, on Wednesday, ensemble probabilities
for combined sub-30% RH and wind gusts of greater than 20 mph
are locally 30-40%. Thus, we may have to watch fire weather
parameters more closely by Wednesday, particularly given our
lack of rainfall for much of the Commonwealth in the last 2-4
weeks.

Later in the week, it is anticipated that the lower-level flow
will turn more southerly and bring increased moisture into the
region. Also, with an approaching cold front from the northwest
and deepening troughing aloft upstream (mentioned above), the
chances for showers should increase.

&&

.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
VFR conditions are virtually certain (100% confidence) through
12Z Monday under the influence of high pressure. Model guidance
is in fair agreement with respect to scattered low-level clouds
across much of central Pennsylvania this afternoon with high
clouds working into the Lower Susquehanna Valley (MDT/LNS) after
sunset. Fog formation looks less likely after 06Z Monday
compared to previous evenings with HREF/RAP model guidance
outlining less low-level moisture.

Outlook...

Mon-Tue...AM valley fog possible; otherwise predominantly VFR.

Wed...Isolated SHRA possible in the afternoon across the far
west at locations such as BFD and JST.

Thu...Widespread SHRA

&&

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

&&

$$

SYNOPSIS...Dangelo
NEAR TERM...Dangelo
SHORT TERM...Dangelo
LONG TERM...Jurewicz/Dangelo
AVIATION...NPB