365
FXUS61 KCTP 112120
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
520 PM EDT Tue Jun 11 2024

.SYNOPSIS...
A pocket of cool air in the mid levels of the atmosphere will
help to create plenty of clouds today with afternoon high
temperatures averaging 5 to 10 degrees below normal for the
date.

High pressure will build over Pennsylvania late today
through Wednesday.

As the high drifts east of the region, heat and humidity will
ramp up for Thursday and Friday, followed by a cold frontal
passage with scattered thunderstorms during the day Friday.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Anomalously cold air in the 850-700 mb layer and shallow
moisture advecting SE from the Lower Glakes will help to
maintain plenty of clouds across the Northern and Western
portions of the CWA today. The clouds are generally stratocu
with bases 2500-3500 ft AGL.

Vertical mixing of dry air above the cloud deck near and to the
SE of the Allegheny Front will create some significant holes in
the mid-late afternoon, while bkn-ovc skies could persist for
much or all of the day near, and just to the east of the RT 219
corridor from the Laurel Highlands to the NW Mtns of PA.

High temps will be in the mid 60s - mid 70s today, once again
5-10 deg below climo.

High pressure will begin to build in Tonight, which will
bring clearing skies and light/variable wind under 4 kts.
Patchy, or even some larger areas of fog are possible across
primarily the Northern Mtns of PA, with overnight lows ranging
from the upper 40s northwest to mid 50s southeast. Air/water
delta Ts should be around 20 deg F.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
Wednesday will be a transition day between much below normal
temps to start the week and warmer weather for Thursday and
Friday. Variable amounts of mid and high clouds on Wed will
have only a minimal impact on the otherwise abundant sunshine
with highs ranging from the low to mid 70s over the Northern
Mtns to the low 80s throughout the Valleys of Central and
southern PA. These readings will be just a few deg F shy of
climo. Winds will be light from the west. PWAT values will
start out around 0.8 inch and will increase to around 1 inch
Wed afternoon, but it won`t feel humid given sfc dewpoints
remaining in the 40s and 50s.

We`re still expecting a warm up for the second half of the
week, with many locations seeing their warmest temps on
Thursday, except perhaps southeast PA seeing temps a few
degrees warmer on Fri. Temperatures on Friday will depend on the
timing of clouds and convection associated with an approaching
cold front. Over the past 24 hours, models have generally sped
up the arrival time and southward progression of the
aforementioned front, now bringing a chance of showers and
thunderstorms to the northern Alleghenies as early as Thursday
night, and then dropping south across central PA during the day
Fri with more numerous showers and thunderstorms.

Despite forecast high temps near 90 across southern zones Thu-
Fri, relatively low levels of humidity (dewpoints 55-65F) will
hold the heat index to just a couple deg above the air temp.
Thus not anticipating heat products at this time. However, the
+15-20 degree swing from temps well below normal early this
week to the warm weather late this week will be noteworthy.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Next weekend looks dry, as a northerly flow of drier air from
Canada is advected into our area. Plenty of sunshine and fair
weather is expected for Saturday and Sunday. Any slight cool
down on Saturday will be short- lived, with warmer temperatures
progged to build back into the area Sunday into Monday. A few
isolated sprinkles could be possible in the northern tier of PA
with weak diurnally driven updrafts on Monday afternoon. The
risk for excessive heat will increase into the middle of the
upcoming week as a large ridge builds over the eastern US.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
Late afternoon update.

Clouds holding on late this afternoon. A few minor adjustments.

Earlier discussion below.

As of 18z Tue, a BKN-OVC stratocu deck was observed across much
of Pennsylvania, with notable clearing over the southwest corner
of PA in the past 2 hours. Cloud bases are generally in the
2500-3500 ft range, but as low as 1500 ft in the northern tier.
Gradual improvement is expected through the late afternoon and
evening hours, with BFD likely the last TAF site to trend to
VFR this evening.

The forecast is more uncertain tonight. We expect most locations
to remain VFR, but there will be some valley fog that develops,
especially in the vicinity of deep river valleys and where the
skies are clear for longest. Some hires guidance also suggests
more widespread IFR or LIFR cigs developing in the northern
Alleghenies into the Endless Mountains, building back on to
whatever cloud mass remains from this afternoon.

All TAF sites should trend to VFR by mid morning on Wed, with
mid-high altocu or cirrus and a light westerly breeze.

Outlook...

Thu...Predominantly VFR w/ no sig wx expected.

Fri...Restrictions possible in CB/TSRA.

Sat-Sun...Predominantly VFR.

&&

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

&&

$$

SYNOPSIS...Lambert
NEAR TERM...Lambert/Colbert
SHORT TERM...Lambert/Colbert
LONG TERM...Evanego/Bowen
AVIATION...Jurewicz/Martin/Colbert