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579
FXUS61 KCTP 191857
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
257 PM EDT Thu Sep 19 2024

.SYNOPSIS...
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*Pleasantly warm this evening with clearing skies and late-
 night valley fog into early Friday morning
*Increasing odds for rain/showers to start the weekend; Fall
 begins on Sunday
*Daytime temperatures peak +5-15 degrees above average into
 Saturday before trending seasonably cooler next week
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&&

.NEAR TERM /THROUGH TONIGHT/...
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A pleasantly warm afternoon and evening will precede clearing
skies tonight with fog developing in the central valleys. The
fog may become locally dense early Friday morning and result in
slowdowns and increased travel times during the peak AM commute.
Low temps will be cooler vs. last night but still above climo in
the 50-60F range.
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&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
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Fog to start Friday; otherwise a mostly sunny and warm day ahead
for mid to late September with max temps in the 75-85F range or
+5-15F above daily climo. Lows will be a bit warmer night/night
with more fog developing late Friday night into early Saturday
morning.

Consensus/blended model data continues to signal increasing
odds for rain showers (and perhaps a PM t-storm) on Saturday in
response to an upper air disturbance and associated frontal
system tracking into the region from the Great Lakes and Ohio
Valley. The emerging precip signal was strong enough to cause a
notable change in the forecast for Saturday which had looked to
be a dry one just a few days ago. The global guidance now suggests
the frontal zone may stall over central PA Saturday night which
could increase/prolong the chance of rain (increase clouds at a
minimum) through Sunday. The low level flow takes on more of an
easterly component with time suggesting more clouds and
potentially lower daytime temps for the first day of Fall.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A trend toward cooler and cloudier weather appears likely into
the middle of next week associated with a cold air damming
scenario ahead of a slow moving warm front in the Ohio Valley
and high pressure over the Canadian Maritimes.

As for rainfall, a weak shortwave and associated plume of
enhanced pwats overrunning the warm front could produce
scattered showers Sunday night into early next week. Upsloping
flow could also yield patchy drizzle over the Central Mtns early
next week. The best chance for rainfall will come during the
middle of the week as an upstream trough approaches the region.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
VFR conditions with light winds and mainly clear skies are
expected through the rest of the day. Model soundings suggest
that fog will form once again overnight across the northern half
of Central Pennsylvania, with BFD, IPT, and UNV being most
likely to see IFR or lower visibilities. The HREF and GLAMP
suggest that fog could be possible (~30% chance) at sites
further to the south as well, but confidence is low. The fog
will dissipate by 14Z and give way to VFR conditions.

Outlook...

Sat-Sun...Valley fog in the morning; otherwise VFR/no sig wx.

Mon-Tue...Scattered showers.

&&

.CLIMATE...
The first day of Autumn 2024 (Fall Equinox) begins at 8:44 am
EDT on September 22nd.

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Fitzgerald/Bauco
AVIATION...Bauco
CLIMATE...Steinbugl/NPB