992
FXUS61 KCTP 042312
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
712 PM EDT Sat May 4 2024

.SYNOPSIS...
Cloudy skies with areas of light rain and drizzle, along with areas
of fog, will persist throughout the weekend. High pressure
slowly building eastward from the central Great Lakes will bring
some drying to northern and central Pennsylvania by Monday and
Tuesday, but the south will remain on the cloudy side with some
showers. The pattern remains unsettled mid to late week with
weather systems bringing rain chances Tuesday night into
Wednesday, and Wednesday night into Thursday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Increasing boundary layer convergence occurring over central PA
early this evening thanks to freshening 850 mb jet in rich deep
layer moisture environment combined with easterly llvl maritime
flow. This is supporting widespread light rain and drizzle
throughtout central PA and holding temperatures from 48 to 52F
over most areas, a far cry from last week`s widespread 80s.

Conditions change very little over the next 6 to 12 hours with
rich deep layer moisture over 1.25" PW advecting into the region
on broad southwest flow west of the upper ridge axis. LLVL
easterly flow around 1029mb sfc high in the Gulf of Maine will
continue to advect maritime airmass into eastern PA. Model
censensus of .25-.5" QPF should result across the area into
Sunday morning. Periods of mainly light rain and drizzle will
persist overnighit with areas of especially higher terrain fog
expected as well. Temps won`t wander far from current readings
through 7AM Sunday.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Sunday looks to be another relatively cool day for early May
due to a persistent southeast flow off of the Atlantic. However,
a slight rebound in warmth is expected over the western and
southwestern periphery of the CWA as steadier rain tapers off.
Fcst highs range from 55F in the Endless mtns and southern
Poconos to ~70F in the far southwest corner of the CWA (near
Confluence in Somerset County).

Scattered diurnal convection appears likely to the west of the
Alleghenies Sunday afternoon which could spill into central PA
late in the day as CAPE values increase. The SPC MRGL risk SWO
clips a portion of Warren County. Everywhere else remains under
general thunder.

The CAD pattern loses its grip Sunday night into Monday as a
weak cold front presses southeast from Lake Erie. This will
allow for the possibility of night time convection along the
cold front. Guidance has been bullish on fog development and the
mention of it has increased in coverage in the wx grids. Fcst
lows Sunday night are +10-20F above climo for early May in the
low 50s to near 60F.

Temperatures are forecast to bounce on Monday with fcst maxes
getting back into the 70-80F range. High pressure and low pwat
air should dry out the northern tier, but nearly stationary
frontal zone will maintain a chance of showers/t-storms over
south central PA through Monday night.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Unsettled weather is expected for the long term period with
multiple chances for showers and thunderstorms. The first chance
will come on Tuesday as a warm front lifts north of the area and
moisture advection increases. The best chance for any showers
or storms on Tuesday will be across the southwestern counties.
Wednesday will be the warmest day of the period with highs in
the upper 70s and 80s as the region will be in the warm sector
of an approaching low pressure system. Most model guidance shows
a weak wave of low pressure tracking to our north during the day
on Wednesday along the warm front ahead of the primary low.
This will bring more showers and storms to the area.

The best chance for widespread showers and thunderstorms
appears to be on Thursday as a cold front moves through. Locally
heavy rainfall will be possible with ensembles showing PWATs
approaching 1.3 inches across the southern tier along with
surface CAPE of 500-1000 J/kg. A few stronger thunderstorms
appear possible as well, as deep layer shear begins to increase
as the upper level trough moves in.

Temperatures will be on a downward trend behind the cold front
and into the weekend. Highs on Saturday will range from the
upper 50s across the northern and western mountains to the mid
to upper 60s for the southeast. There is some disagreement in
the models with respect to rain chances through the end of the
period, but scattered showers appear likely as a couple of
shortwaves ride through the southern edge of an upper low
positioned to our north.

&&

.AVIATION /23Z SATURDAY THROUGH THURSDAY/...
A moist southeast flow preceding a slow-moving warm front in the
Ohio Valley will produce low cigs and rain across the forecast
area through at least Sunday morning. At 22Z, some MVFR cigs are
noted across the eastern half of the state. However, all
guidance points to deteriorating conditions overnight with widespread
IFR/LIFR cigs by early Sunday morning. LIFR cigs are most
likely where the southeast flow is forced to ascend the higher
terrain of Central PA. Strengthening south-southwest winds aloft
will result in marginal LLWS later tonight into Sunday morning.
Bufkit soundings indicate the best chance of LLWS criteria
being met will across the northern tier of the state.

Little improvement in flying conditions are expected over most
of Central PA Sunday, as a moist southeast flow off of the
Atlantic persists. However, model soundings indicate some
modest improvement is possible late in the day along and west of
the spine of the Alleghenies.

Outlook...

Mon...AM low cigs/fog likely.

Tue...Patchy AM valley fog possible, mainly Southern PA. Isold
PM tsra impacts possible Western PA.

Wed...AM low cigs possible NW Mtns.

Thu...Rain/low cigs possible. PM tsra impacts possible
southwest PA.

&&

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

&&

$$

SYNOPSIS...DeVoir
NEAR TERM...DeVoir
SHORT TERM...Steinbugl/Bowen
LONG TERM...Bauco
AVIATION...Fitzgerald