Bratton, Pennsylvania Weather Forecast Discussion

038
FXUS61 KCTP 182300
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
700 PM EDT Thu Sep 18 2025
.SYNOPSIS...
* The final days of summer 2025 will feature above average
  daytime temperatures with no rainfall through the weekend
* Remaining warmer than normal into late September with some
  much needed/light rainfall possible at times next week
&&
.NEAR TERM /THROUGH FRIDAY/...
Beautiful afternoon and evening across CPA with very warm temps
and low humidity. 3PM/19Z observed temps not that far from
daily records at Williamsport (88/1964), State College
(88/1965) and Altoona (87/1965).
A cold front will sink southward from the lower Great Lakes
overnight and should reach the I80 corridor by 8AM/12Z. Latest
hires model data is bullish on bringing post-frontal/upslope low
stratus into the northern tier after 06Z and perhaps even some
spotty/barely measurable light rain or sprinkles. An additional
wrinkle in the near term may be radiational fog formation early
tonight across the northern tier valleys preceding the cold
FROPA and low stratus deck.
Low temps will be in the 50-60F range which is +5-10F above
mid/late September climo.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Low stratus/stratocu deck should gradually thin out by midday
Friday in the north, with a mix of sun and clouds expected
elsewhere. It will be a very warm end to the week particularly
across south central PA with max temps in the 80s or +10 to +15
degrees above the historical average for this time of year.
Aside from lowering dewpoints/minRH, no significant changes were
made to the foundational NBM initialization.
Clear/cool/chilly Fright night-AM Saturday with valley fog. We
leaned lower vs. NBM for minT with some upper 30s likely in the
usual northern tier cold spots.
Cooler trend/not as warm across the board for daytime highs on
Saturday (-1 to -5F north, -5 to -10F south) to start the last
weekend of astronomical summer. There will be plenty of sun,
but the wind from the east will deliver cooler air vs. Friday.
Low clouds are forecast to develop later Saturday night into
early Sunday morning in association with an east to southeast
wind. The clouds will result in a milder minT trend with fcst
lows about +10F warmer across the NW mtns vs. Friday night.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Heading into next week, high pressure will begin to lose its
grip on the region as an upper trough tries to disrupt the
persistent ridge of high pressure aloft. Still plenty of
uncertainty on how much, if any, precipitation will get into
Pennsylvania, but southerly flow ahead of the approaching system
will support continued warmer than average temperatures for the
start of Astronomical fall.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR conditions are virtually certain (~100% confidence) at all
airfields outside of BFD through 00Z Saturday with all model
guidance pointing towards clear skies and light wind (generally
below 5 kts) overnight and scattered cumulus development wind
winds generally between 5-10 kts during the afternoon hours. Low
cloud potential remains increasingly likely based on HREF
probabilities and recent RAP/GLAMP model guidance, especially in
the 09Z-13Z timeframe where there is high confidence (~70-80%)
in IFR/LIFR conditions prevailing. There remains low-end fog
potential at BFD; however the bulk of fog formation is expected
to stay just outside of the airfield. VFR conditions could be
slow to improve at BFD, trending closer to the 13-14Z Friday
timeframe, before VFR conditions are expected through 00Z Sat.
Outlook...
Sat...AM valley fog; VFR.
Sat Night-Sun...Sub-VFR low clouds possible.
Mon-Tue...Rain showers possible; best odds over the NW 1/2 of
the airspace.
&&
.CLIMATE...
Astronomical fall officially begins with the autumnal equinox
on Monday, September 22, 2025 @ 2:19 p.m. EDT. The Autumn 2025
season will last 89 days, 20 hours, and 43 minutes. Daylight
saving time will end just after Halloween with clocks falling
back at 2 a.m. Sunday, November 2, 2025.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Lambert/Banghoff
AVIATION...NPB
CLIMATE...Steinbugl

NWS CTP Office Area Forecast Discussion