York, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

932
FXUS61 KCTP 260850
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
450 AM EDT Sun Jul 26 2026

.WHAT HAS CHANGED...
Augmented wording for Sct TSRA with gusty winds across the Lower
and Middle Susq Valley this afternoon and early this evening.

&&

.KEY MESSAGES...
1) A few gusty thunderstorms possible across portions of the
Lower and Middle Susquehanna Valley this afternoon and evening.

2) Turning more humid and unsettled early in the upcoming week
with the highest probability for showers and thunderstorms
Monday afternoon and evening and again on Tuesday and Tuesday
night.

&&

.DISCUSSION...
KEY MESSAGE 1:  A few gusty thunderstorms possible across
portions of the Lower and Middle Susquehanna Valley this
afternoon and evening.

A weak upper level disturbance embedded in the NW flow aloft
will race SE and over a favorable zone of convergence along a
lee trough that will be situated across the Middle and Lower
Susq Valley this afternoon/early evening.

Surface dewpoints in the low to mid 60s convergence and the
passage of the left exit region of a 90 kt jet max over Ohio and
SW PA late this afternoon will provide the fuel and favorable
larger scale UVVEL for some pulse and small clusters of
strong to potentially svr multicell TSRA across the I-81 and RT
11/15 corridors in southern PA within a fairly narrow corridor
of sfc-based CAPE between 1000-1500 J/KG between 18Z-00Z
today/Monday. SPC has this relatively small portion of
our CWA in a MRGL Risk for SVR TSRA today.


KEY MESSAGE 2: Turning more humid and unsettled early in the
upcoming week with the highest probability for showers and
thunderstorms Monday afternoon and evening and again on Tuesday
and Tuesday night.

A warm front will be moving across western PA Monday
afternoon/evening, followed by a rather potent/digging mid/upper
level shortwave and surface low. This shortwave will help to
amplify a slow-moving upper trough over the Mid Atlantic Region
as we head into the midweek period.

Fcst dewpoints are not all that high for late July, and there
has been a slight downward trend with fcst dewpoints over the
last few days.

Main things supporting showers and storms is a deepening low,
and a large scale pattern that supports significant directional
and speed shear in advance of a quite anomalous 995-1000 mb sfc
low moving over or just north of PA on Tuesday. Hodographs
Tuesday have a broad loop, but winds in the lowest KM are fairly
light, so we`re leaning to the storm type being pulse, but with
0-2KM helicity values peaking around 150 M2/S2 Tuesday, we could
see some transient supercells over Central and Ern PA during
the afternoon.

Previous disc...

The timing of the favorable lift associated with the thermally
indirect, left front quad of the 80+ KT jet max moving across
the Ohio Valley, WVA and southern PA Tuesday afternoon and
evening will help to enhance a low level lee trough and
convection along it. Scattered strong to severe TSRA are likely
Tue afternoon and evening over at least the eastern half of the
CWA with a second line of TSRA likely along the cold front
across NW PA Tuesday afternoon.

&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
Current observations outline LIFR conditions at BFD with fog
and low cloud development currently present across the airfield
as of 06Z Sunday. This trend is likely to continue overnight
with HREF model guidance indicating the 10Z-13Z window for
improving conditions at the airfield. Elsewhere through 12Z
Sunday, it appears that JST/AOO will be most likely to
experience sub-VFR conditions based on most recent GLAMP/NBM
guidance. Not completely sold on this potential with low-level
dry air outlining dew point depression of 5F at JST and the lack
of precipitation at the airfield, thus have taken out mentions
overnight given this lower potential overall. Thus, VFR
conditions area wide outside of BFD have been sent out with the
06Z TAF package with moderate-to-high (70-80%) confidence.

Recent hi-res model solutions paint some chances for SHRA/TSRA
mainly east of UNV (IPT/MDT/LNS) during the afternoon and
evening hours on Sunday, thus have introduced some increased
mentions based on where there is increasing confidence in some
precipitation mentions in this timeframe. The lowest confidence
with respect to the 18Z Sunday to 03Z Monday timeframe is the
timing of SHRA/TSRA popping up along IPT given the wide range in
model solutions at this airfield; however, this appears to be
the airfield that could have most impact. Thus, have highlighted
the general timeframe of precipitation with SHRA and introduced
a narrower window for TSRA mentions where instability will be
the greatest and thus thunderstorm potential will be highest
despite lower coverage. Further southeast, SHRA appear to be
more likely and have nixed TSRA mentions at this time. After 02Z
Monday, signals look fairly foggy across the entire region but
lower confidence exists at AOO/JST/UNV given lower potential for
SHRA/TSRA, thus have limited mentions of sub-VFR conditions.

Outlook...

Mon...Restrictions likely in afternoon -SHRA/-TSRA. Patchy
overnight fog possible.

Tue...Restrictions likely with scattered -SHRA/-TSRA.

Wed-Thu...Restrictions possible as -SHRA/-TSRA becomes less
numerous. Patchy overnight fog possible.

&&

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

&&

$$

WHAT HAS CHANGED...Lambert
KEY MESSAGES...Lambert
DISCUSSION...Lambert
AVIATION...Beaty