Fort Hill, Pennsylvania Weather Forecast Discussion

959
FXUS61 KCTP 201457
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
1057 AM 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 PM THIS EVENING/...
Sfc cold seen pushing south of KIAD/KCBE line per fine line on
dual pol reflectivity from KLWX. Limiting 925 mb streamline
with a longer over-water fetch of llvl/Atlantic moisture from
the ENE was seen veering slightly and helping to form some bkn,
high- based strato cu across the Lower Susq Valley and Scent
Mtns early today. Elsewhere across much of Northern and Western
portions of our CWA, clear skies prevailed under a light ne flow
with high pressure centered over SW Quebec Canada.
08Z temps range from the upper 40s over northern PA where PWAT
values were under 0.50 of an inch to the low 60s across
southern PA with PWATs of 1.0+.
Cloud cover will come in the form of a shallow sct-bkn layer of
040-060 strato cu across the SE 1/4 to 1/3 of our CWA with
sunshine mixing with a bit of cirrus late this morning and this
afternoon in the west.
Afternoon max temps today will display about a 10 deg F range
from north (70F) to south (80F) across the CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
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.
The cool air damming pattern on Sunday suggests some downside
to max temps depending on breakup/mixing out of morning low
clouds.
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.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
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 /14Z SATURDAY THROUGH WEDNESDAY/...
Overall, another pleasant VFR day expected. Patchy valley fog
in northern PA this morning, including near BFD, will dissipate
by 13z. Areas of midlevel stratocu that developed overnight in
portions of central PA will mostly scatter out by mid afternoon.
High clouds will increase in coverage late in the day. There is
a slight chance of a stray shower over the Laurel Highlands late
this afternoon or this evening, but sub-15 pct chance of
reaching JST.
As the sfc flow becomes more easterly and southeasterly
tonight, low stratus will develop across much of central PA with
restrictions likely after 06z. For all TAF sites, the
probability of MVFR or lower cigs approaches 60-80 pct by
daybreak Sunday, with the chance of IFR cigs between 40-60 pct
in the Laurels and the central Mountains, and less than 40 pct
in the lower Susq valley. Conditions will slowly improve through
the day Sunday, with some TAF sites likely improving to VFR.
Outlook...
Sun...MVFR/IFR cigs likely; trending MVFR/VFR by Sunday
afternoon.
Mon-Wed...Rain showers possible; highest chance 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...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Lambert/Steinbugl
LONG TERM...Lambert/Steinbugl
AVIATION...Colbert/NPB
CLIMATE...Steinbugl

NWS CTP Office Area Forecast Discussion