617
FXUS61 KCTP 311807
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
207 PM EDT Sun Aug 31 2025

.SYNOPSIS...
* Dry weather is expected to continue through the middle of this
  week, featuring cool nights, and warm comfortable afternoons
* Aurora Borealis may be visible Monday night; Geomagnetic
  Storm Watch in effect
* Next chance for rain comes Thursday and Friday with a cold
  front

&&

.NEAR TERM /THROUGH TONIGHT/...
Sprawling high pressure centered over the eastern Great Lakes
is dominating our weather this weekend and will remain in
control for the next few days. The result: spectacular fall-like
conditions as we approach the start of Meteorological Fall on
Monday September 1st. Diurnally-driven fair weather cumulus
clouds have developed across northeast PA this afternoon, with
clear skies farther southwest. 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.

Tonight, expect a near carbon copy of the last few with
temperatures trending just a couple degrees warmer. As a
result, the risk of frost is lower and should preclude the need
for an Advisories. A mid-level vort max will drift northward
across the Eastern Seaboard overnight, which could bring some
clouds to our eastern zones (mainly east of US-15). Low
temperatures by Monday morning will range from the upper 30s in
northwest PA to the mid 50s toward Harrisburg. Fog is likely
again in the northern river valleys.

&&

.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 Labor Day. 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. Highs in the 70s areawide is just about perfect
for this time of year, especially on a day when cookouts and
outdoor activities abound.

Another pleasant night Monday night with some valley fog in
northern PA. The most "exciting" aspect of Monday night`s
forecast is the potential for Northern Lights viewing. The Space
Weather Prediction Center has issued a Geomagnetic Storm Watch
for Monday and Tuesday. Aurora Borealis forecasting is
historically tenuous around here, but it will be worth keeping
an eye to the northern sky Monday night to see if you (or your
phone) can get a good view of the astronomical spectacle.


&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
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 for the
long term period. 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.
Gusty southwest winds ahead of an approaching cold front on
Wednesday could also lead to an enhanced risk of fire weather
concerns.

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. Latest WPC QPF for Thursday
paints a fairly widespread 0.50" area across Central PA, which
would be welcome after a prolonged dry stretch. Unless there is
a well- organized or tropical system, QPF tends to decrease at
shorter lead times (drought begets drought is what we say a lot
around here), but time will tell with this one.

In the wake of the cold front next weekend, lake effect rain
showers are expected across northwest PA as cold advection
resumes. Latest ensembles indicate another stretch of below
normal temperatures and frost potential across the typical deep
/ protected valleys of northern and central PA.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Clear skies and light winds will prevail into Monday evening
across the region, as weak high pressure prevails. A few weather
CU and high CI clouds from time to time, but that is about it.

Potential for fog tonight very low, given how dry it has been
and expected dewpoints. A few spots had a very thin layer of
ground fog when I came in this morning.

Potential for fog will edge up some after Monday morning, as
dewpoints come up, but then it has been dry, so would not expect
much fog before later in the week, when we get some showers with
a cold front later Thursday and perhaps lingering into Friday
across the east.

Outlook...

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 expected.

Fri...Showers lingering, mainly across the east.

&&

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

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Banghoff
SHORT TERM...Dangelo/Banghoff
LONG TERM...Dangelo/Banghoff
AVIATION...Martin