000
FXUS61 KCTP 240316
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1116 PM EDT Tue Jul 23 2019

.SYNOPSIS...
Cooler and much less humid air arriving today in northerly
flow. A trough aloft will slowly swing across the state this
week with a surface high pressure system following doggedly
after. Warmer and more muggy air will be returning later in the
week and for the weekend as the high pressure moves off the east
coast.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
830 pm update... The current forecast is in excellent shape, so
just some cosmetic temperature tweaks were made for the evening
hours.

A broken band of showers and thunderstorms continues to slowly
decay early this evening across central NY and central PA. Given
only modest large-scale support in the form of a mid-level
trough axis, waning instability, and weak vertical shear, we
anticipate a continue weakening trend in the next 2-3 hours,
with generally rain-free conditions after 11pm or midnight.

Lows by daybreak are still expected to range from the 50s-lower
60s.

Previous discussion... Main player today is upper trough that
will take its time swinging through over the next few days.
Though airmass is much drier in lower levels, cooler air aloft
helping to produce enough instability/CAPE to generate isolated
to scattered showers and a few tstms along an 850mb N/S oriented
convergence line extending from ROC to BFD to MGW. A localized
wind gust to 30 mph will be poss near any tstms. These will
slowly drift eastward just another county or two over the next
several hours before dissipating early this evening. Clouds will
also linger through the daytime before decreasing overnight,
with patchy fog forming in the deeper valleys of the northern
mountains as lows there drop into the 50s (lows around 60 in the
Susq Valley).

Wed looks like a smaller version of today. With trough still
lingering, more isolated showers again look to pop
midday/afternoon generally over the NW and Laurels.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A rather deep (seasonably-adjusted) upper level trough over CPA
at the start of the period will gradually deamplify into the
weekend. High pressure will dominate the surface pattern as it
migrates slowly eastward from the Ohio Valley off the Mid
Atlantic coast by Saturday morning. A pocket of cool air aloft
may combine with diurnal heating to produce a few spotty showers
over the northern tier during the afternoon on Thursday and
Friday. Otherwise, expect an extended break from the heat and
humidity with mostly dry and pleasant conditions, plenty of
sunshine, and comfortably warm afternoons/cool nights.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Rainfall potential will slowly increase during the period as
more typical summertime pattern becomes established over the
region. Model and ensemble guidance show a frontal system
approaching the area early next week, offering the highest
chance for showers/t-storms.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
What little is left of the shower activity that developed along
the Allegheny Front is quickly dissipating as of 03z. A deck of
mid-level clouds will gradually drift east of the area
overnight, and the clearing skies should lead to patchy fog
development. KAOO is already seeing its vsby drop at this early
hour, and expect other northern and western TAF sites to follow
suite overnight.

Wednesday looks like a near repeat of Tuesday, with an upper-
level trough passing overhead and isolated showers popping up
over the higher terrain during the afternoon hours. Overall,
however, expect generally VFR conditions and a light northerly
breeze.

Excellent flying weather should continue into the weekend.

.Outlook...

Wed-Sun...No sig wx expected.

&&

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

&&

$$
SYNOPSIS...Dangelo/RXR
NEAR TERM...Jurewicz/RXR
SHORT TERM...Steinbugl
LONG TERM...Steinbugl
AVIATION...Evanego