553
FXUS61 KCTP 030301
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1101 PM EDT Sun Jun 2 2024

.SYNOPSIS...
*Scattered showers this evening.
*Hit and miss showers and thunderstorms expected Monday and
 Tuesday as temperatures and humidity ramp up.
*More widespread rain on Wednesday and Thursday precedes a
 cooler weekend with scattered PM showers/storms.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
A weak mid level shortwave tracking over Central PA is
supporting nothing more than a few light showers/sprinkles
across the north-central mountains as of 03Z. Weak large scale
forcing as inferred by model 500-300mb qvec convergence fields,
combined with almost no cape per SPC mesoanalysis, suggests that
coverage will remain sparse as the shortwave moves through the
eastern half of the state after midnight.

Surging low level moisture, combined with a light upsloping
flow, appears likely to result in persistent low clouds over the
Allegheny Plateau overnight, with late night ridgetop fog
possible. Further east, model RH profiles support partial
clearing in the wake of the exiting shortwave late tonight.
However, lack of rain in most areas and mostly cloudy skies
through a good deal of the night argue for a low risk of
radiation fog south and east of the Alleghenies.

Cloud cover and surging dewpoints will result in a milder night
than we`ve seen recently, with lows in the mid 50s over the N
Mtns, to mid 60s across the Lower Susq Valley.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Upper level ridging building into PA favors warmer and drier
weather Mon-Tue. However, isolated, diurnally-driven convection
is possible both days. On Monday, the best chance of an
afternoon shower/tsra is over the northeast part of the forecast
area associated with a weak shortwave diving south across the
Hudson Valley. The upper ridge is progged to lie directly over
PA Tuesday, suppressing convection in general. However, can`t
rule out an isolated PM pulse-type shower/tsra forming on the
ridgetops of Central PA.

Ensemble mean 850mb temps of around 14C supports high temps
Monday ranging from the mid 70s over the highest elevations of
the Alleghenies, to the mid 80s in the Lower Susq Valley.
Ensemble 850mb/2m temp plumes indicate highs may be a degree or
two warmer Tuesday.

Clearing skies and a calm wind may promote patchy valley fog
late Monday night, primarily in the favored deep/river stream
valleys of North Central PA.

The next notable chance for rain arrives on Wednesday afternoon
as a low pressure system drifting across the Great Lakes helps
bring surging Gulf Coast moisture into the northeast. Increasing
clouds on Wednesday will keep temperatures in check with highs most
likely in the mid 70s to low 80s. The chance for showers and
thunderstorms will increase into Wednesday evening.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The most concentrated showers and possible tsra should come
with the passage of the low level jet just ahead of the
cold/occluded front passage Wed PM into early Thursday. Strong
upper level diffluence and +1-2SD pwats support a decent
rainfall for most of the area. Ensemble plumes suggest most
likely areal average rainfall Wed-into early Thu is around a
half inch.

Latest GEFS and EPS indicate drier weather will arrive by
Thursday PM, 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 probable Thu PM
through next weekend, especially over the NW Mtns, associated
with a closed upper low pivoting across the Eastern Grt Lks.
GEFS 2m temp anomalies support highs several degrees below
average Fri-Sun. A decent pressure gradient supports an active
northwest breeze into the nighttime hours, likely holding min
temps near normal for early June.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Rain showers should be east of the central PA airspace by 5-6Z
as forcing wanes. MVFR ceilings will continue for the western
airfields and develop farther east into UNV/AOO/IPT later this
evening through tonight. Fog and IFR Ceilings will be possible
late tonight/early Monday morning for these same spots as
westerly flow results in upslope and stratus development.

Sunrise will bring an improvement to sub-VFR conditions at the
central and eastern terminals. However, the western sites will
take a couple of hours to rise to MVFR then finally VFR. The
instability and left over moisture could spark a SHRA or two
Monday afternoon, but coverage is not expected to be enough to
warrant mention for any site. There is the possibility (15-20%)
for a TSRA at MDT/LNS/IPT in the afternoon, but again have kept
mention out given the low probability at this time.

Outlook...

Tue...AM fog/IFR possible SE. Otherwise, no sig wx.
Wed...Sct SHRA/TSRA with restrictions possible PM.
Wed night-Thurs...CFROPA with numerous SHRA/TSRA. Flight
restrictions likely (70%). IFR possible (30%).
Friday...AM fog poss, sct PM SHRA/TSRA.

&&

.CLIMATE...
Prelim May and Spring 2024 Temperature & Precipitation Rankings

Harrisburg: T12th warmest; 76th driest May
 T3rd warmest; 33rd wettest Spring

Williamsport: 9th warmest; 22nd wettest May
4th warmest; 11th wettest Spring

Altoona: 9th warmest; 13th wettest May
2nd warmest; 3rd wettest Spring

Bradford: 4th warmest; 36th driest May
Warmest; 21st wettest Spring

&&

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

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Fitzgerald
SHORT TERM...Fitzgerald/Banghoff
LONG TERM...Fitzgerald
AVIATION...Guseman/Dangelo
CLIMATE...Steinbugl