Lancaster, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

882
FXUS61 KCTP 141910
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
Issued by National Weather Service Binghamton NY
310 PM EDT Wed May 14 2025

.SYNOPSIS...
* Daily chances for showers and perhaps a few thunderstorms
  through Saturday, as temperatures trend above average.
* A cold front will bring cooler temperatures and less
  rainy/more sunny weather later this weekend and early next
  week.
* Next weather maker arrives for the middle of next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
3 pm update... As a lead vorticity lobe interacts with a deep SE
flow of moisture off the Atlantic, a band of showers and
embedded thunder continues to track across northeast PA and into
central NY late this afternoon. Although this activity will
largely stay east of Tioga and Sullivan counties, a few showers
along its periphery could impact this area into early evening.

In the meantime, another short-wave rotating around the central
Appalachians cutoff low will track northward from VA through
this evening and will bring the likelihood of showers and
embedded thunder for south-central and southwest PA. Although a
cooler, more stable, maritime easterly flow will likely act to
reduce the potential for deep convection and higher rain rates,
we`ll retain the existing Flood Watch for Somerset and Bedford,
due mainly to sensitivity from recent heavy rainfall.

Later tonight, the coverage of shower activity is expected
slowly decrease. Lows by daybreak will range in the 50s to lower
60s.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
315 pm update... A relatively active period continues, as the
cutoff low that has plagued the region recently fills/lifts out,
but is replaced by an approaching and rather vigorous northern
stream upper-level wave.

Lingering energy aloft from the opening up and former cutoff low
could still well produce diurnally favored showers and
thunderstorms on Thursday, with most of the coverage probably
occurring near and east of US-15. Although precipitable water
values look a little lower on Thursday, any sustained convection
over hydrologically sensitive areas will have to be watched.

Later Thursday night into Friday, the remnants of an upstream OH
Valley convective complex will likely track into the
Commonwealth. Although the most likely scenario is that
associated thunderstorms will be in a weakening phase, we`ll
have to watch this scenario as well, with strengthening shear
profiles in place by that time. At this early juncture, SPC has
a marginal risk (level 1 out of 5) of severe storms across
central PA.

At some point, a convective lull in between systems is foreseen
(maybe later Friday into Friday night?), before showers and
storms get re-invigorated on Saturday, ahead of an approaching
cold front.

Temperatures on Friday and Saturday should be warmer than recent
days, although this is somewhat dependent on convective coverage
and timing. At this early juncture, highs in the 70s-lower 80s
are expected.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
The latest model timing now brings a surface cold front through
PA a little faster than earlier model runs (by later Saturday
night). Although some upper-level energy could still produce
isolated showers on Sunday, an overall drier trend should be
underway.

Early next week (Monday and Tuesday), a confluent NW flow
pattern aloft over the Commonwealth will encourage the approach
of expansive surface high pressure and a dry, cooler air mass.

By the middle of next week, once the upper ridge line passes off
the coast, the approach of the next disturbance aloft and
surface warm front should bring a renewed threat of showers.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Extensive cloud cover and cool temperatures will keep the chance
of showers less today. Main area of convection just east of
our area. Few showers just south of far western PA. Thus used
VCSH in the 18Z TAF package.

Expect low CIGS into Thursday morning, with some fog overnight.

As the sfc and upper level low edge just to the east of our
area Thursday morning, expect conditions to improve some by
early afternoon on Thursday.

Outlook...

Fri...Morning storms (some could be strong), improving
conditions in the afternoon.

Sat...Mainly VFR, isolated PM showers/storms.

Sun...Some improvement, as a series of cold fronts move
southeast of the area.

Mon...Mainly dry with VFR conditions. Perhaps a shower
early at BFD and JST, with MVFR CIGS early at these sites.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM EDT this evening for PAZ033-034.

&&

$$

SYNOPSIS...Jurewicz
NEAR TERM...Jurewicz
SHORT TERM...Jurewicz
LONG TERM...Jurewicz
AVIATION...Martin