360
FXUS61 KCTP 261849
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
249 PM EDT Sat Apr 26 2025

.SYNOPSIS...
* Showers and a few thunderstorms will be possible this
  afternoon across eastern PA.
* Dry conditions with gusty northwest winds accompany cooler
  temperatures late this evening through Monday.
* Warmer temperatures prevail on Tuesday with a severe
  thunderstorm risk during the afternoon and evening hours.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front associated with a surface low tracking to our north
continues to push eastward across Central PA this afternoon and
is now east of Altoona/State College/Williamsport. The main
area of heavy rain from this morning has now exited to the east
and scattered showers have developed ahead of the front. SPC
mesoanalysis shows that there is roughly 500-1000 J/kg of CAPE
across eastern PA, so a couple of thunderstorms will be
possible as well. The marginal risk of severe weather clips the
southeastern corner of Lancaster County, but the severe threat
appears low across the area with weak shear in place. That being
said, can`t completely rule out a few strong wind gusts in any
thunderstorms that develop before the front moves off to our
east later this afternoon. Westerly wind gusts of 20 to 25 knots
have developed west of the Allegheny front and will increase to
around 30 knots across the entire area into the evening.

Some breaks in the clouds can be seen on satellite ahead of the
cold front, though areas farther to the west remain overcast as
westerly flow has ushered in a low stratus deck. Model RH
profiles suggest that these low clouds will stick around for
much of the night tonight and may even expand to the east
slightly. A few light showers or some drizzle could also develop
over the northern tier. Much cooler and drier air will work
into the region overnight and temperatures will fall into the
30s and 40s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
Skies begin to clear out on Sunday as high pressure builds in,
though most guidance supports wind gusts of 20 to 30 knots for
much of the day as we mix to around 5000 feet and tap into some
stronger winds aloft. Model soundings show dry air above a weak
inversion, so have undercut NBM dewpoints during the day on
Sunday which results in RH values in the 20 to 30 percent
range. While recent rainfall has likely led to slightly higher
fuel moistures, it is unclear just how much they have risen.
Regardless, conditions look favorable for fire spread on Sunday
and we will continue to collaborate with PA DCNR. More
information can be found in the fire weather section below.

Clear skies with light winds are expected Sunday night, allowing
for efficient radiational cooling. Frost potential appears
limited to areas where the growing season remains inactive.
Under a dry airmass on Monday, have also undercut NBM dewpoints
while also slightly increasing temperatures, allowing for MinRH
values in the 20-30% range; however, winds will be much lower
on Monday with high pressure centered over the region. This
should help to limit the potential for wildfire spread compared
to Sunday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
On Tuesday into Wednesday, an amplified upper trough
progressing across the northern tier of states will push a warm
front/cold front progression through the Commonwealth. This
should lead to notably warmer temperatures within the surface
warm sector Tuesday afternoon, followed by potentially active
showers and thunderstorms ahead of an approaching cold front
later Tuesday into Tuesday evening. Ample instability
(1500-2000J/kg CAPE) and sufficient shear (30-40kts) will
combine with the left entrance region of a 75kt mid-level jet
streak to produce the potential for multicell thunderstorms and
perhaps some supercells. The greatest risk for severe weather
appears to be across the northwest mountains, though storms will
likely drift southeastward across PA Tuesday night and bring a
decreasing - but nonzero - threat of severe weather all the way
into the Lower Susquehanna Valley.

The cold front will get hung up just south of the Mason-Dixon
Line on Wednesday and Thursday before lifting northward again on
Friday. The result will be better chances for rain/clouds across
the southern tier and more sunshine/dry conditions farther
north. Temperatures will be fairly consistent through the end
of the week with highs in the 60s north and 70s south,
corresponding to +5 to +10F above average for this time of year. The
next phased upper system makes a run at the eastern CONUS
Thursday and Friday, with another round of showers and
thunderstorms likely to close out the work week.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
The cold front has now cleared all airfields with northwesterly
winds building in behind it under variably cloudy skies. Winds
will gust 20 to 30kts this afternoon and overnight. A few
scattered showers remain possible this evening and overnight,
but no significant accumulation or restrictions are expected.

IFR/LIFR ceilings will persist at BFD and JST for much of the
evening and overnight hours as is typical in this type of
pattern. MVFR ceilings are favored at UNV and AOO, with VFR
expected at IPT, MDT, and LNS.

Gradual improvement in conditions is expected overnight with
clearing building in/clouds eroding away from southeast to
northwest. All airfields should see VFR conditions by daybreak
on Sunday. Gusty winds will taper off Sunday afternoon and
evening.

Outlook...

Sun-Mon...VFR/No sig wx expected.

Tue...Showers and possibly a few t-storms with sub-VFR probable
into Tuesday night.

Wed...Lingering showers across western PA.

Thu...Showers and storms, especially in southwest PA.

&&

.FIRE WEATHER...
Earlier rainfall has likely led to some recovery of fuel
moistures, though the magnitude of this recovery is still
unknown given showers and thunderstorms in the forecast through
the evening hours. Collaboration with PA DCNR is expected later
this evening/early Sunday morning to reassess the fuel
situation heading into a potentially more impactful fire weather
day on Sunday.

A return to lower relative humidity values is progged by all
model guidance on Sunday, with strong winds due to a fairly
tight pressure gradient. Current forecast for Sunday outlines
south-central Pennsylvania with the lowest RH values (20-30%)
with a fairly large footprint (covering much of central
Pennsylvania) in the 35-35% MinRH range on Sunday. Gusty
northwesterly winds are expected to begin during the predawn
hours on Sunday, with the best window for 20-foot winds
exceeding 20 mph coming during the afternoon/evening hours,
coinciding with the timeframe for lowest RH. Given this set-up,
two of the three ingredients for RFW consideration look probable
across much of the area with fuel moistures the main forecast
element that is uncertain at this time.

&&

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

&&

$$

SYNOPSIS...Bauco/NPB
NEAR TERM...Bauco
SHORT TERM...Bauco/NPB
LONG TERM...Jurewicz/Banghoff
AVIATION...Banghoff
FIRE WEATHER...NPB