-- Discussion containing changed information from previous version are highlighted. --
756
FXUS61 KCTP 010443
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1243 AM EDT Sat Jun 1 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 TODAY/...
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 /TONIGHT 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/...
Medium range guidance points to fair and warm weather Tuesday,
with ridging at the surface and aloft over PA. Falling heights
and surging pwats ahead of a deepening upper level trough over
the Grt Lks will result in showery weather Wednesday and
Thursday. At the surface, the latest GEFS and EC both indicate
an occluded front will traverse Central PA Thu PM, as a triple
point low passes south of the area. This scenario favors
relatively stable air over the forecast area with a limited risk
of severe weather. Ensemble plumes suggest most likely areal
average rainfall Wed-Thu between 0.5 and 1 inch.

Latest GEFS and EPS indicate drier weather Friday, as the low
level jet/plume of highest pwats shift east of PA with the
exiting cold/occluded front. However, scattered, diurnally-
driven showers appear possible, especially over the NW Mtns,
associated with the deep upper trough/closed low parked over
the Grt Lks.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
High pressure over the region today will keep light winds and
clear skies across the area into this evening. The airmass is
too dry to see fog early today.

Clouds will be on the incease by early Sundaay morning across
the far west, and later in the morning across eastern areas.

Conditions will lower by 12Z Sunday across the far west, and
later in the day across the Susquehanna Valley.

Outlook...

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...
-- Changed Discussion --
Frost Advisory until 7 AM EDT this morning for PAZ005-006-010-
011.
-- End Changed Discussion --

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Fitzgerald/Steinbugl
SHORT TERM...Fitzgerald/Steinbugl
LONG TERM...Fitzgerald
AVIATION...Martin
CLIMATE...Steinbugl