081
FXUS61 KCTP 190101
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
901 PM EDT Thu Jul 18 2024

.SYNOPSIS...
High pressure will bring mainly fair weather with seasonable
temperatures through the end of the week. Humidity increases
a bit this weekend with some areas seeing a scattered shower
or thunderstorm on Saturday, but most areas will remain dry. The
next best chance for rainfall will come late Monday and Tuesday
of next week as a slow moving frontal system lifts across the
region.

&&

.NEAR TERM /UNTIL 8 AM FRIDAY MORNING/...
A few high clouds will continue to linger into this evening
over the eastern counties, but mainly clear skies eventually win
out later tonight with the passage of the upper trough. Surface
ridging, high pressure, and an associated low PW air mass
should result in the coolest night we have seen a quite a while
with temps close to 50 across the NW. The weakest gradient and
most efficient radiational cooling is anticipated over the NW
Mtns, where we have slightly undercut NBM min temp guidance.
Air/water temp differences of >25 degrees should result in
patchy late night fog in the deep river/stream valleys of the
Alleghenies.

&&

.SHORT TERM /8 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Another day of tolerable warmth and generally comfortable
humidity levels is in store on Friday, thanks to high pressure
over the region. An approaching warm front is likely to spread
increasing clouds/humidity into at least Southern PA Friday
night, but the odds of any rain look slim. Patchy fog could
develop again Friday night into Saturday morning across the NW
mtns given the increasing moisture and scattered cloud cover
expected.

A short wave disturbance will bring increased rain chances for
the afternoon on Saturday when isolated to scattered coverage
of shra/tsra develops over parts of the Laurels, SC Mountains
and Central Mountains. Temps start to creep up on Saturday,
along with dewpoints, but will be even more pronounced on Sunday
as high temps across the south approach 90 once again Sunday
afternoon.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
With the large-scale, upper-level pattern next week, it appears
that amplified ridge axes will stay in place across the
Intermountain West, as well as from the Southwestern Atlantic
into the Southeastern CONUS. In between these two ridge axes, a
mean upper-level trough axis will extend from Eastern Canada
into the Midwest and the Ohio Valley.

In general, the above described pattern will keep excessive
heat suppressed to the south and southwest of the Commonwealth.
However, southwesterly flow aloft will bring increasingly humid
conditions locally. Also, the proximity of the aforementioned
upper trough, as well as several surface fronts, will bring the
likelihood of diurnally driven (mainly during the afternoon and
evening hours) showers and thunderstorms, especially in the
Tuesday-Thursday time frame. The silver lining here is that
additional beneficial rains could be in the offing for drought
stricken sections of PA.

For the most part, we can expect daytime highs in the 80s and
overnight lows in the 60s, which is rather seasonable for mid to
late July. Some of our northern mountainous areas may see
afternoon highs stay in the upper 70s, while normally hotter
sections of the Lower Susquehanna Valley could sneak into the
lower 90s.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
High confidence continues for predominately VFR/unrestricted
conditions across central PA through the day on Friday.

One exception is potential for patchy fog overnight into early
Friday across northwest PA, thus maintained a small window at
KBFD for fuel alternate-IFR visibilities.

NW surface winds 5-10 kt should become light/nearly calm
overnight and Friday across the airspace.

Outlook...

Sat through Mon... Primarily VFR/unrestricted conditions. Patchy
late night/early morning fog and low ceilings are possible.

Tue... More widespread afternoon and evening showers and
thunderstorms could lead to at least brief restrictions.

&&

.CLIMATE...
The max temperature hit 100 degrees at Harrisburg Tuesday,
7/16/24. The last time KMDT hit 100 was back on July 19, 2020.

&&

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

&&

$$

SYNOPSIS...DeVoir/Bowen
NEAR TERM...DeVoir/Bowen
SHORT TERM...DeVoir/Bowen
LONG TERM...Jurewicz
AVIATION...Jurewicz/Gartner
CLIMATE...Steinbugl