077
FXUS61 KCTP 151410
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1010 AM EDT Sat Jun 15 2024

.SYNOPSIS...
Canadian high pressure will build southeastward into
Pennsylvania this weekend, providing sunshine, seasonable
temperatures and low humidity. For next week, an anomalous
subtropical ridge will build over the East Coast accompanied by
an extended period of hot and generally rain-free weather.

&&

.NEAR TERM /THROUGH TONIGHT/...
In the late morning hours, already seeing fair wx cu develop
over the higher terrain of the northern mountains and the Laurel
Highlands. We should continue to see fair wx cu develop this
afternoon, although skies will generally remain mostly sunny
across the area.

Canadian high pressure building southeastward into PA will
provide fair weather this aftn with a good deal of sunshine,
seasonably warm temps and low humidity. Dry air above a weak
inversion in the model soundings suggest dewpoints will fall
below NBM guidance this afternoon, so have leaned toward the
drier MAV guidance.

Model guidance indicates there will be some cirrus drifting into
PA tonight in advance of a weak shortwave cresting the ridge
axis over the Grt Lks. However, model RH profiles indicate it
should be relatively thin and not significantly affect
radiational cooling, which otherwise looks favorable under the
surface high. Have therefore undercut NBM min temps and leaned
toward the cooler MAV numbers, with lows ranging from the low
40s in the coolest northern valleys to the mid 50s in the urban
centers of the Lower Susq Valley.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
The surface high should pass east of PA Sunday, resulting in a
slightly warmer return southerly flow. Model 850mb temps near
14C support highs a few degrees higher than today, with max
temps ranging from the mid 70s over the mountains north of KIPT,
to the low 80s most other locations. A building subtropical
ridge along the east coast and the passage of a warm front early
Monday will herald the arrival of much warmer early next week.
Warm temps aloft should suppress convection and 850mb temps
surging to near 17C supports highs Monday afternoon in the mid
80s to low 90s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Little change with the late evening update outside of limiting
chances of diurnal showers/storms on Tuesday. Have kept chances
into the middle/end of the week due to some uncertainty.

Prev..

Confidence is increasing for a heat wave later next week with
the potential for 4-6 consecutive days of MaxT 90F+ across
much/all of central PA. The prolonged nature of this heat wave
may have cumulative adverse effects on vulnerable populations
exposed to heat, with heat related illnesses possible if proper
precautions are not taken. Outdoor workers and individuals with
preexisting health conditions will be among those most at risk.

Tuesday through Thursday (and potentially Friday-Saturday) are
progged to be the warmest days of the week, with most guidance
showing a 595-600 dm 500 hPa ridge centered over the area.
Southerly flow will usher in higher dew points Tuesday that will
allow for heat index values to reach 100-105 degrees over a
large portion of the area. With the large high pressure system
overhead, winds will be light and clouds will be few. Keep in
mind that the sun angle will be at its max next week as we
approach the summer solstice. The intense sun and lack of a
breeze will exacerbate the impacts of heat. Beyond Thursday,
uncertainty begins to develop regarding the shape of the ridge
and the possibility of convection firing along the periphery of
the high pressure system, but the potential for highs in excess
of 90F continues through Saturday.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
12z update... Any fog patches should burn off quickly by
13z, given a deep layer of dry air aloft and large-scale
sinking motion. There is high confidence of VFR conditions
(80-90%) for the remainder of the valid TAF period (through 12z
Sunday).

One small fly in the ointment could be KBFD later tonight (after
04-06z), as patchy river valley fog over northern PA could
impact this site. Given the very dry air mass, confidence in
this scenario (10-20%) is low enough to keep out of the TAF at
this time. We`ll continue to monitor with later forecasts.

Surface winds should be light (mostly under 5 kt) through
13-15z, then pick up out of the NW to 8-10 kt, before
diminishing again by/after 00z.

Outlook...

Sat-Wed...Predominantly VFR, with building heat next week.

&&

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

&&

$$

SYNOPSIS...Fitzgerald/Evanego
NEAR TERM...Fitzgerald/Evanego
SHORT TERM...Fitzgerald
LONG TERM...Colbert/NPB
AVIATION...Jurewicz/Evanego/RXR