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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCTP 241026
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
626 AM EDT Tue May 24 2022

.SYNOPSIS...
High pressure over New England will remain in place through the
middle of this week. A cut off upper low will approach
Pennsylvania late this week, then slowly lift across the region
next weekend. The upper low is likely to exit the area by
Memorial Day, as anomalous upper level ridging expands eastward
from the Ohio Valley.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weakening shortwave is progged to slowly shift east across
Virginia later today, keeping the deepest moisture and associated
shield of steady rain south of Pa. However, gradient between a
weak surface low over North Carolina and strong high pressure
across New England will result in a persistent east-southeast
flow off of the Atlantic today. Model soundings indicate there
may be sufficient moisture and orographic lift to support a bit
of very light rain/drizzle over the southern tier today.
Elsewhere, early sunshine over northern Pa will likely give way
to increasing clouds by afternoon, as stratus creeps northward.

Cloud cover and a flow off of the cool Atlantic should hold
temperatures 5-10 degrees below average today over most of the
region. However, GEFS 2m temp anomalies support near average
temps over the northwest corner of the forecast area, where
skies will be brighter.

Model guidance indicates surface ridge will build south into Pa
tonight, shifting the moist easterly flow south of the state
and bringing clearing skies to most of central Pa. Breaking
clouds, light winds and high relative humidity going into the
evening will likely promote patchy late night valley fog.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
A building upper level ridge along the east coast should ensure
mainly dry weather Wednesday and Thursday. However, a persistent
low level southeast flow off of the Atlantic will maintain
relatively cool conditions. Have undercut NBM max temps both
days due to its warm bias in easterly flow/cold air damming
scenarios. Model RH profiles support partly sunny skies for most
of central Pa Wednesday, but upsloping stratus could
potentially affect the Laurel Highlands and south-central
mountains.

As high pressure retreats off of the coast, increasing low
level moisture advection is progged to result in stratus
expanding northward over the area Wednesday night into Thursday,
with even some patchy drizzle possible over parts of eastern Pa,
where progged RH in the sfc-850mb layer nears 100pct. Scattered
Thursday PM showers are possible over the Allegheny Plateau in
vicinity of a slow-moving warm front over western Pa.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
11 pm Monday update... On the large-scale, there is good
agreement amongst our various ensemble prediction systems that
an upper-level closed low will gradually fill and move eastward
towards the Commonwealth later this week, leading to a high
likelihood of showery conditions Thursday and Friday.

Over the long holiday weekend, uncertainty grows, with more
model disagreement creeping into the picture. The EC is among
the most progressive and optimistic guidance sources, indicating
that the aforementioned upper disturbance will move into the
western Atlantic and be replaced locally by rising heights and
improving weather. Meanwhile, the GEFS has a significant number
of members showing the same system cutting off close to PA,
signaling that unsettled weather could last much longer.

For now, we saw no compelling reason to deviate substantially
from the NBM, which shows gradual improvement on Saturday, then
largely dry and seasonably warm weather Sunday and Monday.
Hopefully, model consensus will improve as we approach Memorial
Day weekend.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Generally VFR at BFD,AOO, UNV, IPT, MDT, and LNS. MVFR cigs have
already made it to JST as on 10Z. Ceilings expected to continue
to bring all airfields to MVFR by midday and persist through the
day on Tuesday. Light rain is possible along the southern tier
Tuesday evening and night.

A return to VFR is possible by early Wednesday morning, but may
be delayed if low clouds are slow to move out.


Outlook...

Wed...MVFR cigs could persist due to continued easterly flow.

Thu...Predominantly VFR, with brief restrictions possible in
scattered SHRA/TSRA.

Fri-Sat...Reductions likely in SHRA/TSRA as low pressure
approaches from the Ohio Valley.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...Fitzgerald
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald
LONG TERM...Jurewicz
AVIATION...Evanego/Gutierrez