272
FXUS61 KCTP 051612
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1212 PM EDT Fri Jul 5 2024

.SYNOPSIS...
*Very warm and humid summertime pattern with above average
 temperatures continues into next week
*Showers and thunderstorms are possible in spots today and
 Saturday followed by a rain-free end to the first weekend of
 July

&&

.NEAR TERM /THROUGH TONIGHT/...
Mesoanalysis shows broad but light cyclonic flow around a weak
sfc low (1007 mb) located between KUNV and KIPT. This low was
along an ill-defined, quasi stnry front near the I-80 corridor
with a weak, lee-trough extending down through the Mid and
Lower Susq Mainstem.

Rich moisture with PWAT values between 1.5 and 1.9 inches across
all but the Western Mtns of our CWA topped by sharp mid level
ridging and a notable mid level cap with 700 mb temps of +9-11C
has led to a mostly cloudy to cloudy morning so far with very
little precip of note other than some stray light showers.

We should see breaks in the cloud area slowly develop during the
mid to late afternoon with isolated to widely sctd showers/TSRA
developing, mainly across the Western Mtns.

Convection will continue to form/advect from the west late today
through early tonight (similar to the evening of the 4th, but
perhaps just a bit greater in areal coverage).

Previous...

The latest hires guidance continues to favor a suppressed
convective scenario for today - leaning bearish for t-storms and
potential severe risk - with very limited development through
the afternoon and into the evening hours. Early day cloud cover
and shower activity (leading to reduced instability) appear to
be the primary contributors. CAM signal remains consistent in
ramping POPs higher across the NW zones closer to 00Z.

CAPE and shear profiles are supportive of isolated severe
t-storm potential with a large MRGL risk SWO covering most of
the CWA. However, timing remains a wildcard and could end up
being to late in the day/after dark.

Another hot and humid summer day across CPA with highs in the
85-95F range. With the humidity (dewpoints 70-75F), it will feel
like 100-102 degrees across portions of south central PA
particularly in the lower Susquehanna Valley. Max HX values
ticked higher above the century mark and we coordinated with
WFO PHI on the issuance of heat advisory from noon to 8PM. A
couple of showers/t-storm will could linger overnight which
will be very warm and muggy with low temps 65-75F.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Focus for t-storms will shift to the eastern periphery of the
CWA on Saturday PM along and ahead of a weak cold front. Despite
a very moist/unstable environment, most model guidance suggests
limited storm coverage likely owing to neutral height falls and
weak llvl convergence. That said, still can`t rule out a couple
of strong t-storms over eastern PA.

High pressure builds in Saturday night and provides a slightly
less humid and dry (rain-free) end to the first weekend of July.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
All medium range guidance supports fair weather and above
average temperatures into early next week with upper level
ridging indicated over the northeast. At the surface, high
pressure is progged to build over Pennsylvania Sunday, then pass
off of the east coast early next week. The return southerly
flow should result in an uptick in heat/humidity early next
week.

Diurnally driven showers and thunderstorms appear possible on
Monday based on recent GEFS plumes but guidance continues to
suggest a better chance of precipitation on Tuesday with the
arrival of a cold front during the afternoon hours. There is
still a fair amount of uncertainty with regards to the cold
front clearing eastern Pennsylvania later on Wednesday, so have
retained PoPs through this timeframe. Towards the end of the
period, deterministic guidance begins to outline high pressure
influence into the region; however, given so much uncertainty
earlier in the forecast period have opted not to deviate from
NBM PoPs at this time.

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
LLVL moisture pooling around a weak area of low pressure
centered over the West Branch of the Susquehanna at midday will
continue to create plenty of clouds through early this afternoon
with areas of stubborn MVFR. Conditions will gradually improve
to VFR in most places after 18Z.

Isolated to scattered showers and thunderstorms will be
possible again later this afternoon, though coverage looks to be
initially more limited than what occurred Thursday.

VFR will likely persist through much of tonight with the only
restrictions coming in the form of a scattered shower or
thunderstorm. Lower cigs could reintroduce restrictions by
Saturday morning.

Outlook...

Fri...Sct TSRA w/ possible impacts; Mainly PM w/ highest
coverage across the west.

Sat...Sct to Nmrs TSRA areawide, highest chances SE in PM.

Sun...AM fog possible; otherwise, no sig wx.

Mon...SHRA possible SE late PM; otherwise, no sig wx.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ026>028-035-
036-056-057-059-063>066.

&&

$$

SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Fitzgerald/Martin/NPB
AVIATION...Lambert/Bauco/Bowen