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399
FXUS61 KCTP 121923
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
323 PM 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 /UNTIL 6 AM THURSDAY MORNING/...
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 /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
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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.

The approaching cold front will bring a chance of showers and
thunderstorms to the northern Alleghenies as early as Thursday
night, and then drop south across central PA during the day Fri
with more numerous showers and thunderstorms. There is still
uncertainty with the timing of this precip and associated clouds,
which will influence how high temps can rise across south
central PA. Latest hires guidance has precip holding off until
at least late afternoon in the southeast, allowing temps to
first rise into the upper 80s to low 90s. Most places will see
rainfall totals between 0.20 and 0.50 inch on Fri, with locally
higher amounts possible in heavier downpours.

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.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Dry conditions are expected to prevail through Tuesday
afternoon outside of some isolated diurnally driven showers
across the northern tier Monday afternoon and across much of
north and western PA Tuesday afternoon.

An extended period of above average temperatures is
increasingly likely as a large ridge builds across the eastern
US. This will allow for MaxTs and MinTs +10-15F above
climatology for the middle of June. There remains some model
difference with respect to the strength of the ridge, but
generally better agreement of abnormally warm temperatures
extending northward into PA.

Less humid conditions on Monday will bring heat index values
into the upper 90s, with some locations across southern PA
pushing close to the 100F mark. Humidity during the afternoon
hours will increase the risk for excessive heat on Tuesday with
some potential for heat index values in the 100-105F across the
Lower Susquehanna Valley. Humid conditions will continue into
Wednesday with heat index values slightly lower than Tuesday,
but still anomalously warm even for this time of the year. The
Climate Prediction Center has placed much of eastern PA in a
Moderate Risk for Excessive Heat for the middle and end of next
week, outlining the longevity of heat across the region.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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VFR conds expected through the TAF period as a broad area of
high pressure remains in control. Low levels look too dry for
much fog Thu morning, but can`t rule out patchy fog in the
deeper river valleys. Sfc winds will be from the west to
southwest at 5-10 kts with gusts to 15-20 kts possible Thu
afternoon mainly in northwest PA.

Outlook...

Fri...Restrictions possible in CB/TSRA.

Sat-Sun...Predominantly VFR.

Mon...Mainly VFR, chance of convection mainly north.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Lambert/Colbert
NEAR TERM...Lambert/Colbert
SHORT TERM...Lambert/Colbert
LONG TERM...Banghoff/NPB
AVIATION...Jurewicz/Colbert