York, Pennsylvania Weather Forecast Discussion

632
FXUS61 KCTP 272322
AFDCTP
Area Forecast Discussion
National Weather Service State College PA
722 PM EDT Sat Sep 27 2025
.SYNOPSIS...
* Increasing clouds today with light rain most likely south of
  the Turnpike/east of I-81 this afternoon into early tonight
* Partly to mostly sunny and very warm to close out the final
  weekend of September; start of another extended dry spell
* Mild/warm start early next week before turning seasonably
  cooler with stretch of dry weather continuing into October
&&
.NEAR TERM /THROUGH SUNDAY/...
A check of surface observations and webcams show the steady
light rain generally covering southern PA along and south of
the turnpike. Over southern Somerset county, precipitation
enhanced by a southeast flow has allowed for 0.50 to 1.00" to
fall in this area. Six hour FFG is around 2.00".
Expect the area of light rain to slowly move north through the
day with sprinkles or isolated showers toward I-80.
Hires data shows rain exiting southeast PA by 12Z Sunday as
high pressure starts to move in from the Great Lakes. Clearing
from west to east along with residual moisture and light/calm
wind will promote fog formation which may become locally dense
and significantly reduce the visibility during the predawn/post
sunrise period.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
AM fog will give way to partly/mostly sunny and very warm
conditions to close out the final weekend of September on
Sunday. Max temps fcst in the 75-85F range are 10 to 20 degrees
above the historical average for late September. High pressure
settling over CPA Sunday night favors more radiational fog into
early Monday morning.
Monday also will be quite warm by end of September standards
with fcst highs very close to/a few degrees cooler vs. Sunday.
High pressure continues to dominate the pattern, setting up
what should be an extended period of dry weather through next
week.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Confidence is now increasing in an extended period of dry wx
for next week. This is due to better model agreement in the
evolving blocking pattern, showing the area remaining under the
influence of high pressure both at the sfc and aloft Tue-Fri.
Backdoor cold front will allow seasonably cooler/chilly air to
filter into the area to start October as 1030+mb Canadian high
moves southeast from Hudson/James Bay into New England. This
airmass change will drop daytime max temps by 5-10F day/day Wed
& Thu and increase the risk of late night/early AM frost
particularly in the northern tier where NBM min temps are fcst
in the mid 30s.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Rain will continue to move across southern PA through the rest
of the evening and will largely remain confined to areas south
of I-80. Most central PA airfields are VFR as of 23Z, with the
exception of JST, where IFR cigs/vsby have developed. VFR
conditions will likely return there by 01Z.
Overnight, there is a strong signal in much of the guidance for
fog and low stratus over most of the region. The best chance for
IFR or lower conditions will be at BFD, JST, and IPT, but all
TAF sites will have the potential to see fog and/or low stratus
prior to sunrise. The fog and low clouds will dissipate during
the morning as high pressure begins to build into the area,
giving way to VFR condition with light northwesterly winds.
Outlook...
Mon-Tue...Low confidence in sub-VFR cigs/rain across the
southern/eastern portions of the airspace. Mainly VFR across the
central and northern two thirds of PA.
Wed-Thu...No sig wx.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...Tyburski
SHORT TERM...Steinbugl/Tyburski
LONG TERM...Tyburski
AVIATION...Bauco

NWS CTP Office Area Forecast Discussion