Cress, Pennsylvania Weather Forecast Discussion

698
FXUS61 KCTP 201900
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
300 PM EDT Sat Sep 20 2025
.SYNOPSIS...
* Above average daytime temperatures to close out astronomical
  summer 2025
* Trending mostly cloudy by the end of the weekend with rain
  most likely starting our across the northwest Mountains Monday
  afternoon or evening, then spreading across the remainder of
  Central PA late Monday night and Tuesday.
* a few periods of scattered showers expected Wednesday through
  Friday with Saturday showing showery conditions persisting
  based on the US GFS and Canadian guidance, while and the
  European and German models indicate dry conditions with a
  fair amount of sunshine and a light breeze out of the north.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High cirrus clouds can be seen on the latest satellite imagery
streaming in from the south west. These high clouds are
associated with a weak surface low positioned over the southern
Ohio Valley. Small areas of convection have been noted over far
southwestern Pennsylvania, but with the cold front from
yesterday now well south of the Pennsylvania/Maryland border our
dry air will prevent any kind of convection from initiating
within our CWA. Afternoon max temps today will display about a
10 deg F range from north (70F) to south (80F) across the CWA.
Low clouds are forecast to develop tonight into early Sunday
morning in association with an increasingly moist ESE upslope
flow. Locally dense, east-facing slope/ridgetop fog and
widespread low stratus signal is now showing up in the hires
model QPF field and "goal-post" fcst soundings. The cloud cover
and moist easterly flow will certainly result in a milder minT
trend with fcst lows about +10F warmer across the northern half
of the fcst area vs. Friday night/AM Saturday.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
The cool air damming pattern on Sunday suggests some lower max
temps across central and eastern Pennsylvania depending on
breakup/mixing out of morning low clouds. The coolest temps will
be associated on the downslope side of the easterly flow, along
areas of sinking air in the valleys.
The greatest chance for rain/showers during the period will be
late Sunday night into early Monday across the NW zones along a
NEWD lifting warm frontal zone and LLJ. High pressure to the
east will keep any rain showers to a minimum east of I-99 and
south of I-80.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Strong sfc high shifts to the Northeastern Seaboard early next
week. This will allow a +tilt upper level trough and llvl
frontal boundary to move southeast from the Great Lakes bringing
the best odds for rain particularly on Tuesday focused across
the northwest 1/2 of central PA.
Confidence is increasing for a more southern track to the slow
moving cutoff low late next week and weekend, with an increasing
probability of dry/pleasant cool conditions Friday through
Sunday. The ICON and EC and its ensembles have been the most
consistent with their handling of this system and keeping it`s
impacts minimal if any here in Central PA.
GFS`s jet core is across James Bay Canada for the Fri-Sun
9/26-9/28 period, but the northern stream flow veers and becomes
more nwrly with the passage of a significant and fast moving
short wave in that northern branch of the jet. 00Z EC is much
more northwesterly and 300-400 NM further to the south with its
main upper level jet, which places much of PA in the sweet spot
for confluent flow aloft and deep dry air with low daytime
humidity.
Latest...06Z Sat run of the NBM v4.3 6 via WSUP viewer shows
6-hourly POPS AOA 15 percent for much of the CWA SAT 9/27, after
some potentially minor WAA ahead of the upper trough at POPS of
20-25 percent Friday 9/26.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
High clouds are beginning to filter into western Pennsylvania
and will gradually overspread the area this evening. Recent
ECONUS satellite imagery outlines cumulus development west of
the area; however, the bulk of this activity is expected west of
JST/BFD this afternoon, thus VFR conditions will continue with
~100% confidence through 00Z Sunday.
Easterly-to-southeastern flow later this evening and into the
overnight hours will promote low stratus development across much
of the forecast area. Formation is expected first across the
Laurel Highlands (JST/AOO) in the 07-09Z Sunday timeframe and
gradually expanding to encompass all airfields by into the Lower
Susquehanna Valley 09-11Z Sunday timeframe. High-end ceiling
forecast place all airfields in MVFR flight restrictions after
onset through ~16-18Z Sunday with the most plausible ceiling
forecast pushing closer to IFR restrictions at all airfields
outside of MDT/LNS with moderate-to-high (60-80%) confidence. In
terms of improvement, some signals in recent HREF/GLAMP
guidance does indicate improvement across the south- central and
southeastern airfields (AOO/MDT/LNS) in the 15Z-18Z timeframe.
Low (< 30%) confidence in this improvement at AOO have kept
mentions out of the 18Z TAF package; however, low-to- moderate
confidence (~40-50%) exists in improvement at MDT/LNS.
Outlook...
Mon-Thu...SHRA and PM TSRA with sub-VFR conditions possible.
&&
.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...Lambert/Steinbugl
NEAR TERM...Lambert/Bowen
SHORT TERM...Lambert/Bowen
LONG TERM...Lambert/Steinbugl
AVIATION...NPB
CLIMATE...Steinbugl

NWS CTP Office Area Forecast Discussion