York, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

197
FXUS61 KCTP 191614
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1214 PM EDT Sat Jul 19 2025

.SYNOPSIS...
* More clouds and humidity today with the best odds for an
  afternoon shower or thundershower along the southern tier of
  CPA
* A few strong thunderstorms are possible on Sunday associated
  with a cold frontal passage
* Multi-day dry spell with comfortable humidity for the early to
  middle part of next week; heatrisk returns Thursday into next
  weekend

&&

.NEAR TERM /THROUGH TONIGHT/...
Late morning visible imagery and 925 theta-E and wind at that
level is very insightful regarding the pesky area of somewhat
thicker cloud cover and low-topped scattered showers that were
impacting the Susq Valley this morning. 10-15 kts of southerly
wind at that level blowing orthogonal to the tight theta-E
gradient with notable streamline convergence too at that level
was advecting and pooling low level moisture over our eastern
counties. High Res member and ensemble guidance shows this area
of showers slowly diminishing across the Mid Susq Valley, but
becoming more focused across the Lower Susq Valley where an
additional several hundredths of an inch of rainfall is likely.


Elsewhere, skies across the Western Half of PA will feature a
mix of sun and clouds through the afternoon with late PM
isolated to scattered showers between I-80 and I-76 and near
zero POPs across the Northern Tier.

Previous Disc...

Wavy front near the MD line lifts to the north/east as a warm
front today. This will allow for increasing low level moisture
and a more humid afternoon vs. yesterday. Fcst highs in the
upper 70s to mid 80s may be tempered a bit by anticipated cloud
cover (more clouds than sun). HREF (along with individual CAMs)
signal for heavy rain is mainly to the south of the MD line;
however WPC does include the southern tier of CPA in the D1 SLGT
risk ERO. So while the best odds for a thundershower or locally
heavy downpour are confined to this part of the CWA, we feel
the greatest heavy to potentially excessive rain risk is
farther south outside of our CWA into MD/VA and toward the
Delmarva (late).

Max POPs for the tonight period shift to the NW and SE corners
of the forecast area based on the latest hires blend/NBM. The
pcpn zones appear tied to convectively enhanced shortwaves or
meso features that evolve from the peak heating hours through
late evening. There is still some uncertainty in the precip
timing/placement heading into Sunday. Min temps in the mid 60s
trend +5-10 degrees warmer over the northern tier with a
noticeable increase in mugginess vs. Friday night/AM Saturday.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A cold front will traverse the area on Sunday, suggesting some
rain shower or a thunderstorm are likely in most places.
However, the 3hr HREF PMM signal suggests this may be too
bullish as CPA could reside in local minimum in convection with
higher coverage to the southwest (Ohio Valley) and in the
Northeast (New England). SPC keeps the majority of the forecast
area in a MRGL level 1 out of 5 risk for an isolated damaging
t-storm wind gust, but confidence is relatively low given the
weak HREF precip signal.

Confidence is considerably higher that the front penetrates well
south of the MD line Sunday night through Monday night. This
will set the stage for comfortably cooler and drier (less
humid) air to filter into CPA through early next week.

Max temps Sunday afternoon will still be very warm downwind of
the Allegheny Mtns with highs 85-90F. Highs on Monday will be
about 3-7 cooler vs. Sunday, but the most noticeable/refreshing
change will be to overnight temps which should dip into the 50s
in most locations Monday night with even some upper 40s in the
northern tier! Under favorable radiational conditions, the
cooler min temps should trigger the 20-25F water-air threshold
and allow fog to form in some of the river and stream valleys.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Comfortable conditions with near to slightly below normal mid
summer max temps and low afternoon humidity continue Tuesday
into Wednesday as high pressure retreats off the New England
coast.

Model and ensemble data show a building heat dome/590+dm 500mb
ridge expanding over the area for late week into the weekend.
This will translate into a return to hot/humid late July
sensible wx conditions. Some isolated/scattered airmass or
terrain induced convection is possible beneath the upper level
ridge Thu/Fri, but higher POPs lean toward next weekend likely
tied to the arrival of the next frontal system/weak shortwave
trough.

&&

.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
Scattered light showers will continue through the early
afternoon acrs the Susq Valley and may cause brief visibility
restrictions if they happen to move directly over an airfield.
The stratus across the Susq valley will be slow to dissipate
today and may persist into the mid afternoon. A warm front
lifting north into Pennsylvania will trigger showers and
thunderstorms across the southern third to half of the region
in the afternoon, some of which could produce heavy downpours.

Cloud cover will briefly decrease this evening before increasing
once again ahead of an approaching area of weakening convection
from the west. These showers and thunderstorms will likely
reach western terminals around 06Z Sunday. Additionally, weak
southeasterly flow will transport Atlantic moisture in from the
east, which will cause MVFR ceilings to redevelop at IPT, MDT,
and LNS after 06Z.

Outlook...

Sun...Numerous showers and thunderstorms anticipated.

Mon-Wed...Dry conditions.

&&

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

&&

$$

SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...Lambert/Bauco