-- Discussion containing changed information from previous version are highlighted. --
124
FXUS61 KCTP 141542
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1142 AM EDT Fri Jun 14 2024

.SYNOPSIS...
A cold front over the Great Lakes will push southeastward
across Pennsylvania this afternoon into this evening,
accompanied by showers and thunderstorms. This front will be
followed by Canadian high pressure building in for this weekend,
bringing lower humidity. After that, the big story will be
building heat as a subtropical ridge builds over the eastern
United States next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A batch of showers is breaking out across the central mtns and
middle Susq Valley late this morning, so have upped PoPs there.
Already seeing showers/storms pop up over western PA, and this
activity will continue to expand and make it`s way eastward
into central PA this afternoon.

Model guidance pushes the upper trough and associated cold
front through Central PA this afternoon/evening, accompanied by
showers and thunderstorms. Diurnal heating of a relatively
moist pre-frontal air mass, combined with strong large scale
forcing ahead of a potent shortwave diving into the base of the
approaching trough, will result in an uptick in convection
along the front as it pushes into the area this aftn. Modest
instability and deep layer shear approaching 40kts supports
organized convection this afternoon with a chance of isolated
severe weather along the I-80 corridor and the Lower Susq
Valley, where HREF UH values are >75. The bulk of convection-
allowing guidance indicates the greatest risk of severe weather
will progress from the Central Mtns between 17Z-19Z, to the Susq
Valley between 19Z-21Z.

Strong large scale forcing ahead of the upper trough and
seasonably high pwats support likely POPs this aftn across much
of Central PA. Ensemble plumes indicate just a few tenths of an
inch rainfall for most locations, although localized 1-2+"
amounts are possible in any persistent downpours.

Any evening showers/tsra should exit the Lower Susq Valley by
late evening, as the cold front pushes east of the
commonwealth. High pressure building in behind the front should
bring clearing skies, cooler air and lower humidity overnight.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Canadian High Pressure building southeast into PA will bring
fair weather this weekend, with abundant sunshine and seasonably
warm days. However, ideal conditions for radiational cooling
appear likely Sat night under the surface high, resulting in
min temps several degrees below mid June normals. Expect
daybreak readings to range from the mid 40s over the N Mtns to
mid 50s across the Lower Susq Valley. Very dry air above a weak
inversion in the model soundings suggest dewpoints will fall
below NBM guidance, especially Saturday, so have leaned toward
the drier MAV guidance.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
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 to +15F above climatology for the
middle of June. Model differences have become slightly better
resolved with respect to the strength of the ridge, outlining
higher confidence of abnormally warm temperatures extending
northward into PA.

Less humid conditions on Monday will bring heat index values
into the mid-to-upper 90s, with some valley locations across
central/southern PA pushing close to the 100F mark. Tuesday will
likely be the warmest day with most guidance showing a 597+ dm
ridge centered over or just to the east of the area. With the
surface high off to the east, southerly flow will usher in
higher dew points that will allow for heat index values to
reach 100-105 degrees over a large portion of the area. Humid
conditions will continue into Wednesday and Thursday with
anomalously warm conditions continuing into the end of the week.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
An approaching cold front will kick off scattered showers and
thunderstorms this afternoon into this evening across central
PA. Some activity is already moving into the western highlands
as midday approaches, and this will progress eastward and
expand this aftn. With that being said, the majority of the
day will feature VFR conds, with only brief reductions and
potentially gusty winds in the vicinity of storms.

The front will push east of the area tonight, bringing an end
to any lingering shower/storm activity. After that, we are in
for a nice stretch of weather with predominantly VFR conds
prevailing through the weekend.

Much of next week will feature VFR conds as well, although a
heat wave is expected to build across the eastern United States.

Outlook...

Sat-Tue...Predominantly VFR, with building heat next week.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...Fitzgerald/Evanego
NEAR TERM...Fitzgerald/Evanego
SHORT TERM...Fitzgerald
LONG TERM...Bauco/NPB
AVIATION...Lambert/Evanego