846
FXUS61 KCTP 031409
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1009 AM EDT Wed Jul 3 2024

.SYNOPSIS...
High pressure will push off of the Mid Atlantic coast today. A
dying cold front will push in from the Great Lakes tonight,
then stall out over the area late this week. Low pressure
tracking north of Pennsylvania will drag a cold front through
the state Saturday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Midlevel ACCAS tells of the increasing deep layer moisture
across central PA this morning as H5 ridge axis retreats
eastward. 850mb temps on the rise, too and there will be a
noticeable uptick in humidity by this afternoon as a southerly
flow increases ahead of a weak cold front over the Great Lakes.
Diurnal heating and surging low level moisture should result a
fair amount of afternoon cumulus, especially over the western
mountains.

Temperatures will be a few degrees above normal over the W Mtns
and near average elsewhere, translating to highs well into the
80s areawide. Moisture advection and low level convergence along
an approaching low level jet could potentially support a
shower or thunderstorms in northwest PA this evening. A cold
front will move into the region overnight and weaken as it
approaches. It will help focus the potential for showers and
thunderstorms mainly north and west of the I-99/I-80 corridor
through daybreak Thursday. Rainfall amounts should generally
remain less than a quarter inch, but isolated amounts over 0.75
inches are possible. Clouds and increasing humidity will result
in low temperatures in the mid 60s to lower 70s by Thursday
morning.

&&

.SHORT TERM /THURSDAY/...
A mostly cloudy day is in store for the Fourth of July with a
noticeable uptick in humidity. Dewpoint temperatures will soar
into the 70s across much of the region. Morning showers and
storms associated with the decaying cold front will gradually
move southeast through the day and should remain scattered in
coverage. The front will be located over southern PA by Thursday
afternoon, which is where most of the shower activity should be
concentrated for any 4th of July and/or fireworks festivities.
Highs on Thursday afternoon will generally be in the 80s with a
few spots potentially reaching 90 degrees in the southeast
before convection arrives.

The threat for severe weather and flash flooding remains
relatively low and is maximized (Marginal risk) along and south
of I-76. The realization of any downburst winds or flash
flooding will likely be contingent on some breaks in the clouds
to generate instability. Bulk shear near the front will be
sufficient for organization, but CAPE may be lacking owing to
persistent cloud cover. Regardless, the chance of showers and
storms should be monitored for anyone who plans to take part in
outdoor festivities to celebrate Independence Day.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
The front is progged to stall out in the vicinity of Southern
PA Thursday night, then return north as a warm front Friday
ahead of low pressure lifting across the Grt Lks. Falling
heights and surging pwats ahead of an upstream shortwave and
associated surface low lifting across the Grt Lks should bring a
round of showers/tsra in the Friday PM to Saturday timeframe.
Current guidance suggests the shortwave and bulk of the large
scale forcing will pass north of PA, leading to unimpressive
mean qpf in the ensemble plumes of 0.25 to 0.50 inches Fri PM to
Saturday.

The bulk of guidance now supports fair and seasonable conditions
Sunday into at least early Monday, as surface ridging and drier
air work in behind the cold front. Showers and storms return to
the forecast for early next week as another wave of low
pressure tracking to our north brings a cold front through the
region.

Temperatures in the long term forecast look above average,
especially overnight lows Wednesday through Friday night, when
EPS pwats are 150pct of normal.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
VFR conds will prevail today with southerly flow gusting 15-20
kts, highest in the north. A cold front will approach tonight and
lay out W-E over the state on Thurs. The deep moisture Wed PM
and Thurs will allow for sct- nmrs showers and TSRA. Included
VCSH in BFD TAF starting 03/20Z and MVFR cigs/vsby in showers
with thunder possible after 23Z. The first batch of showers is
expected to fizzle as it moves southeast through tonight, with
additional showers and storms developing in the humid
environment on Thu, especially south of BFD.

Outlook...

Wed night...TSRA NW (IFR poss), dry SE with no impacts.

Thu...AM low cigs and isold SHRA possible W Mtns. Sct PM TSRA
impacts possible over all the airspace, but mainly S of I-80.

Fri...sct TSRA, impacts possible, mainly PM, highest covg W.

Sat...sct-nmrs TSRA areawide, highest SE in PM.

Sun...AM fog poss. Otherwise, no sig wx.

&&

.CLIMATE...
June 2024 was the warmest June on record for Bradford with a
mean temperature of 66.6F, breaking the old record of 65.8F set
in 2021.

June 2024 was the 3rd warmest June on record for Harrisburg with
a mean temperature of 76.0F.

&&

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

&&

$$

SYNOPSIS...DeVoir/Fitzgerald
NEAR TERM...DeVoir/Fitzgerald/Banghoff
SHORT TERM...Fitzgerald/Banghoff
LONG TERM...Fitzgerald/Bauco
AVIATION...Gartner/Colbert
CLIMATE...Colbert