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023
FXUS61 KCTP 140320
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1120 PM EDT Thu Jun 13 2024

.SYNOPSIS...
High pressure will pass off of the Mid Atlantic coast today, as
a cold front pushes into the Great Lakes. This front will cross
Pennsylvania on Friday, followed by Canadian high pressure
building in for this weekend. An anomalous subtropical ridge is
likely to build over the East Coast next week, bringing
increased heat and humidity.

&&

.NEAR TERM /THROUGH FRIDAY/...
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The few showers that developed earlier this evening across the
southeast have dissipated and mainly dry conditions are expected
into the early morning. Some patchy fog could develop
overnight, mainly across the eastern half of central PA with
mainly clear skies, light winds, and increasing dew points.

High clouds will begin working their way into the northwest
overnight ahead of an approaching trough. The cloud cover will
begin to thicken towards sunrise and a few showers will be
possible as well, though most of the rain should hold off until
the late morning. Temperatures overnight will range from the low
60s across the northern and western mountains, to the upper 60s
farther to the southeast.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Model guidance pushes the upper trough and associated cold
front through Central PA Friday, accompanied by a good chance of
showers and thunderstorms. A couple of shortwaves will be moving
through the larger trough, with the first moving into the
northern half of the area during the late morning/early
afternoon. Showers and thunderstorms will move into the
northwest around noon and will spread southeastward with the
cold front. As they progress through the area, they will enter
an increasingly unstable environment, with most guidance showing
1000-2000 J/kg of MLCAPE developing across the southeastern half
of the region. Deep layer shear of 40 to 50 knots will support
some organization and a few severe storms will be possible. The
main threat looks to be damaging winds with steep low level
lapse rates and fairly deep boundary layer mixing, though hail
will be possible as well. Later in the afternoon, mid level
flow begins to increase across the Lower Susquehanna Valley as a
second shortwave moves in from the west. This will allow for
more storm development into the evening.

Strong large scale forcing ahead of the upper trough and
seasonably high pwats support POPs in the 60-80pct range Friday
over most of Central PA. Latest ensemble plumes indicate just a
few tenths of an inch rainfall for most locations, with isolated
1-2+" amounts in any storms.

Any evening showers/tsra over the southeast counties should end
shortly after sunset Friday, as the cold front exits the state.
High pressure building in behind the front should bring
clearing skies and cooler air Friday night.

Abundant sunshine and seasonal temps are expected Saturday, as
the high pressure system and associated low-pwat air mass builds
into the region. The center of high is progged to pass over
Central PA Saturday night, resulting in favorable conditions for
radiational cooling and low temperatures in the 40s and low
50s. This will be the last time we see temperatures in the 40s
in PA for the foreseeable future...

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
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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.
-- End Changed Discussion --

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Late evening update.

A few showers got going over the far southeast earlier this
evening, but a cap at mid levels and loss of heating has made
it hard for the showers to hold together over our area. Still
a few just south of the PA, MD border as of 10 PM.

Earlier discussion below.

For the 00Z TAF package, looking at a dry evening so far. One
small shower formed for a couple of minutes earlier just before
6 PM, but is gone now.

Later tonight/early Friday, as a cold front approaches, lower
clouds and a band of showers/thunderstorms will approach the
Commonwealth from the NW. Expect the activity to weaken as it
heads southeast late.

Models still trying to form a band of showers that could edge
into the far southeast later tonight, but so far, not sign of
anything. Temperatures on the warm side, but not all that humid
for shower formation.

Showers and storms work to the east and south on Friday, with
some potential for gusty winds with storms. This will depend on
the amount heating, timing of the activity, and the amount of
phasing with the lee side trough.

Still expect showers and storms to taper off from late afternoon
into the evening. Upper level forcing may result in the activity
across the far south and east to be slow to taper off.

Anyway, used a TEMPO group later Friday to cover any storms with
brief gusty winds.

Clearing out nicely over the weekend, as drier air builds into
the region from the north.

Outlook...

Sat-Sun...Predominantly VFR.

Mon and Tue...Mainly VFR. Isolated afternoon/evening TSRA
possible, with any restrictions brief in nature.

&&

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

&&

$$

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