682
FXUS61 KCTP 121424
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1024 AM EDT Wed Jun 12 2024

.SYNOPSIS...
High pressure will be centered over the Commonwealth today,
supplying abundant sunshine and warmer temperatures, followed by
a further increase in heat for Thursday and Friday as the high
drifts off the Mid Atlantic Coast.

A cold frontal passage on Friday will spark a round or two of
showers and scattered thunderstorms, some of which could produce
gusty winds, frequent lightning and hail.

After a dry and warm weekend, a ridge of high pressure will
bring an increased risk of excessive heat early next week with
highs in the 80s and 90s and heat index values possibly
exceeding 100F.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today will be dry and pleasant. Abundant sunshine will be
accompanied by a few bands of cirrus and altocu along with
afternoon fair weather cu. Highs will be in the mid to upper
70s across the higher terrain and low 80s in the Lower Susq
Valley. These readings will be within a few degrees of climo.
Sfc dewpoints in the mid 40s to low 50s will lead to min RH
values of 30 to 45 percent this afternoon.

Tonight will be tranquil and comfortably cool with min temps
near 50F in the perennial cold spots across the Northern Mtns
and Laurel Highlands and mid to upper 50s elsewhere.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Many locations will see their warmest temps on Thursday, except
for perhaps portions of southeast PA, where temps could be a
few degrees warmer on Fri. Highs are expected to range from the
low 80s in the northern tier to near 90 across the southern
valleys.

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.

SPC`s Day 3 outlook paints a MRGL risk for SVR TSRA across much
of Central PA, while a SLGT Risk covers a small portion of our
Eastern zones (the Western Poconos, south through the greater
Harrisburg, Lebanon and Lancaster areas).

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 is 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 with a beautiful
weekend in store. 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.

By Tuesday, the risk for excessive heat will increase as a
large ridge builds over the eastern US. There remains quite a
bit of spread in model guidance, but potential exists for heat
index values topping 100F in southeast PA Tuesday - Thursday
next week. The ECENS is more bullish with the strength and
northern extent of the ridge of high pressure into PA, which
would result in higher temperatures and heat index values. The
GEFS is a bit cooler with a weaker high and potential convection
associated with a shortwave moving along the ridge, but still
indicates the potential for excessive heat.

Based on this anomalous pattern, the Climate Prediction Center
has placed much of eastern PA in a Moderate Risk for Excessive
Heat for the middle of next week (Wednesday - Friday).

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
12z update... Patchy river valley fog over the northern tier is
expected to burn off quickly this morning (by around 13z). We
have a fairly high degree of confidence (80-90%) in this
scenario. In the meantime, brief restrictions are possible at
KBFD and KIPT.

Otherwise, VFR will prevail, given the expectation that a very
dry air mass will be traversing the region over the next 24
hours or so.


Surface winds look light, generally 5 kt or less.

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/Colbert
NEAR TERM...Lambert/Colbert
SHORT TERM...Lambert/Colbert
LONG TERM...Banghoff/Evanego
AVIATION...Jurewicz/Colbert