164
FXUS61 KCTP 302334
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
734 PM EDT Thu May 30 2024

.SYNOPSIS...
Canadian high pressure will build southeast into Pennsylvania
Friday and Saturday. The high will pass off the East Coast by
late this weekend into early next week, then a cold front will
likely traverse the state next Thursday.

&&

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Cu are dying, but it did sprinkle (trace) for 10 minutes at
AOO. So, a couple of people could have had a drop or two, but
not worth a mention of measurable precip (PoP).

Nearly ideal conditions for radiational cooling are setting up
tonight across the western half of PA, as the upper trough lifts
out and Canadian High Pressure builds in, accompanied by clear
skies, dry air and a calm wind. We continue to lean towards the
cooler guidance (MAV) and close to the 10th percentile NBM mins
which reach the upper reaches of the favorable ranges for frost.
Dry boundary layer, warmer stream temps and fairly warm ground
may preclude frost potential, but collaborated a Frost Advy
headline for my northern tier and NW Mountain counties with BUF
and BGM from ~midnight through 7AM Fri. A large water/air temp
difference of >25 degrees also favors patchy late night fog in
the deep river/stream valleys of the NW Mtns.

&&

.SHORT TERM /7 AM FRIDAY MORNING THROUGH SATURDAY/...
Little changes to the going forecast for Friday and Saturday
with this cycle. Large scale subsidence and low- pwat air
points to abundant sunshine Friday, as high pressure pushes into
the state. Mixing down 850mb temps of around 8C translates to
highs from the upper 60s to mid 70s. Friday night should be
another cool one, as the surface high builds directly over PA,
resulting in clear skies, a calm wind and min temps below NBM
guidance. The airmass in general should be moderating, so expect
readings not quite as cool as tonight.

Upper level ridging is progged over PA by Saturday, as the
surface high slips off of the East Coast, resulting in a mostly
sunny and warmer start to the weekend. GEFS 2m temp anomalies
Sat afternoon are few degrees above climo, translating to highs
of 75-80 over most of Central PA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A shortwave trough moving through the region late Saturday
night into Sunday. This feature will bring the next chance of
showers and thunderstorms to central PA.

Longer range guidance shows multiple shortwaves moving through
the region into the middle of next week bringing renewed chances
for showers and storms. PoPs have decreased for Monday, which
now looks like it will be a generally dry day. Chance or greater
PoPs return for Tue-Thu.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Some gusty winds are still remaining in the area as sunset
approaches. Winds are expected to diminish within the next 2-3
hours across the region and skies are expected to clear out. VFR
conditions are likely to persist through tonight and into
tomorrow.

Dewpoints will be quite low tonight, thus expecting
mainly clear skies with very little potential for fog overnight
into Friday morning, except for the deepest river valleys.
Patchy frost could be present in the NW mountains this evening
as air temperatures dip into the mid 30s. VFR and dry weather
will continue into Friday afternoon.


Outlook...

Fri-Sat...Mainly clear skies with VFR conditions.

Sun-Tue...Showers and thunderstorms possible.

&&

.CLIMATE...
WILLIAMSPORT: A RECORD LOW TEMPERATURE OF 36 DEGREES WAS SET AT
WILLIAMSPORT PA EARLY THIS MORNING. THIS BREAKS THE OLD RECORD
OF 37 DEGREES SET IN 1949.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from midnight tonight to 8 AM EDT Friday for
PAZ004>006-010-011-037.

&&

$$

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