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000
FXUS61 KCTP 260308
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1108 PM EDT Thu Apr 25 2024

.SYNOPSIS...
High pressure will provide dry cool and dry conditions with
widespread frost and freeze conditions expected Friday morning.
Clouds will increase late Friday leading to a chance of showers
Friday night and into the weekend before it turns much warmer
for Sunday and even warmer still for most of next week.

&&

.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
The thicker of the high clouds are slipping to the SE and
revealing only a small patch of lower clouds in
Somerset/Bedford. However, lots of guidance expands this patch
of clouds through the night with help from the gently upsloping
SSE flow. Overall, the current forecast covers this. Now, the
temps are trailing the forecast dip by a few degs. The
dewpoints are still very low across the nrn half of the CWA.
That should allow them to catch up. The main trouble with temps
right now is the SE where temps are the clouds have just
dissipated/left and there was recently a 20KT gust at LNS.
Dewpoints there are still in the u30s. But, we expect the temps
in the SE to get back on track shortly as the pressure gradient
relaxes. Will continue to hold all the frost/freeze flags as is.
There is the potential for some AM fog in the SE, too, with
those higher dewpoints. Lack of recent rainfall is a negative
for fog, though.

&&

.SHORT TERM /7 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Friday will be another fair day under the influence of
retreating high pressure, with return flow freshening over
western areas, and especially the Laurel Highlands. Rain free
wx conditions will continue with morning sun mixing with high
clouds throughout the day and max temps trending warmer into
the upper 50s to lower 60s. Showers along a warm front are
likely to move into the western Alleghenies very late Fri night
or early Saturday morning based on the latest operational
model/ens consensus.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
An approaching warm front will result in a cloudy and relatively
cool Saturday, with a chance of showers accompanying the passage
of a weakening low level jet. Weak large scale forcing under an
upper level ridge should result in minimal rainfall. Most likely
rainfall by Sat PM based on ensemble plumes ranges from around
0.2 inches over the N Mtns, to just a few hundreths over the
southeast counties. Brightening skies and markedly warmer
conditions appear likely Sunday, as the warm front lifts north
of the region. However, ensemble plumes indicate scattered PM
convection is possible, especially over the N Mtns, where
progged pwats are highest and temps aloft coolest.

Fair and unseasonably warm weather is likely Monday, as
anomalous upper level ridge crests over the state. Mean 850mb
temps near 15C supports max temps in the low to mid 80s. All
medium range guidance points to a good chance of PM convection
Tuesday associated with the passage of a mid level shortwave.

Diverging model solutions and greater uncertainty then creep
into the forecast the second half of next week. Upper level
ridging and above average temperatures look very likely.
However, timing differences exist with regard to an upstream
trough and associated cold front late next week. Expect a
widespread round of convection to accompany the front either Thu
PM or Friday.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
High pressure passing north of PA will provide most of Central
PA with VFR conditions and light winds tonight. However, lingering
low level moisture could potentially result in a period of low
cigs/fog across parts of Southern PA around dawn. Current model
guidance indicates the odds of reductions are relatively low
(<25pct) at AOO, MDT and LNS. However, model soundings and
ensemble prob charts support a >50pct chance of MVFR cigs at JST
and even ~25pct chance of IFR cigs around dawn.

The threat of low clouds/fog will diminish Friday, as drier air
mixes to ground level. However, ensemble prob charts suggest an
upsloping southeast flow could potentially result in lingering
MVFR cigs across the high terrain of Somerset County through the
afternoon.

Outlook...

Sat...Scattered shra. IFR cigs possible Central Mtns.

Sun...AM low cigs possible, mainly N Mtns. Isold PM tsra
possible.

Mon...No sig wx expected.

Tue...Sct PM tsra impacts possible.

&&

.FIRE WEATHER...
Fuel moisture may fall below 10% over the next two days. With
light winds today, the risk of fire spread remains very low.
However, return flow around departing high pressure on Friday
may increase the potential for spread on Friday afternoon.

MinRH this afternoon (Thu) is forecast to drop to 15-25% over
the northern half of the area with potential downside to 10%.
MinRH over the southern tier districts along the MD line is
forecast between 30-40%. The wind will <10 mph from the
north/northeast.

MinRH is forecast to recover a bit Friday afternoon bottoming in
the 25-40% range. However, the wind will increase from the south
southeast with gusts to 20 mph at times over the higher terrain
along the southern Allegheny Plateau.

Increasing low level moisture/dewpoints along with some rain will
limit fire weather concerns this weekend.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 2 AM to 8 AM EDT Friday for PAZ004-005-010-
011-017-018.
Frost Advisory from 2 AM to 8 AM EDT Friday for PAZ019-024>028-
045-046-049>053-056-057-059-063-065-066.

&&

$$

SYNOPSIS...DeVoir
NEAR TERM...DeVoir/Dangelo
SHORT TERM...DeVoir
LONG TERM...Fitzgerald/NPB
AVIATION...Fitzgerald
FIRE WEATHER...Steinbugl