-- Discussion containing changed information from previous version are highlighted. --
094
FXUS61 KCTP 010018
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
818 PM EDT Fri May 31 2024

.SYNOPSIS...
*Pleasant rain-free end to May and splendid start to June
*Chance of rain returns Sunday
*Trending warmer, more humid, and more unsettled next week

&&

.NEAR TERM /THROUGH SATURDAY/...
Ideal radiational cooling setup again tonight (with abnormally
dry/low pwat air in place and sfc ridge axis overhead) supports
minimum temps at or below the 5-10th percentile NBM or closer
to the tabular MAVMOS (which verified much better last night)
particularly in the northern tier. The end result is another
late season frost risk focused over the NW Mtns, where a frost
advy was issued for 1-7AM Saturday. Air/water spreads exceeding
25 degrees should also support fog in the deep river/stream
valleys north of I-80 late tonight.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Upper level ridging over PA will ensure fair weather Saturday.
The surface high will slip off the East Coast, resulting in a
warmer southerly return flow, with 850mb temps supporting highs
ranging from the mid 70s over the N Mtns, to the low 80s in the
Susq Valley. Warm advection aloft should spread increasing
cirrus into the region Saturday. However, model RH profiles
suggest it will be relatively thin, so mostly sunny wording
should suffice.

High clouds should continue to increase/thicken Saturday night
ahead of shortwave trough and associated sfc low tracking
eastward from the Ohio Valley. The bulk of latest model guidance
tracks a weak surface low just south of PA, likely resulting in
a period of rain Sunday PM. Cloud cover and an associated lack
of instability in the models indicates thunderstorms are
unlikely. Current NBM max temps are in the 70s Sunday. However,
later shifts may have to dial back the temps depending on the
arrival time of any rain. Latest 2m temp ensemble plumes are
widely diverging, with most members cooler than the current
forecast. Ensemble mean qpf suggests most likely rainfall Sunday
PM of <0.20 inches.

Passage of the shortwave should result in drier weather Monday.
However, the combination of a lingering frontal boundary south
of PA and high pressure to the north could result in persistent low
clouds, especially over Southern PA.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Extended timeframe looking similar to previous thinking and
guidance with multiple shortwaves moving through the region
Monday night through most of next week bringing renewed chances
for showers and storms. NBM advertises chance to likely POPs
from Monday night through Thursday, with much drier and cooler
weather likely by next weekend.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Light winds and mainly clear skies are prevailing across central
Pennsylvania airspace this evening. Tonight would make for a
good radiational cooling night, but with a lack of moisture fog
formation will be difficult. Patchy fog is possible in NW PA,
but confidence is low (<20%), thus a mention has not been made
in the 00Z TAF package for BFD.

Winds will remain light tomorrow with VFR conditions continuing
across the area.

Outlook...

Sat...Mainly clear skies with VFR conditions.

Sun...PM Sct showers and thunderstorms

Mon...Patchy AM fog, slight chance of PM t-storms.

Tue-Wed...Showers and thunderstorms possible.
-- End Changed Discussion --

&&

.CLIMATE...
With only 1 day left, the preliminary monthly summary for May
2024 would be notably warmer than the historical average
(ranking in the top 5-25th warmest) with near to above normal
precipitation. CLMs should be issued overnight on the midshift.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 1 AM to 7 AM EDT Saturday for PAZ005-006-
010-011.

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Fitzgerald/Steinbugl
SHORT TERM...Fitzgerald/Steinbugl
LONG TERM...DeVoir/Dangelo/Colbert
AVIATION...Bowen
CLIMATE...Steinbugl