525
FXUS61 KCTP 061848
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
248 PM EDT Sat Jul 6 2024

.SYNOPSIS...
* A stray shower or thunderstorm possible acrs the far NW and SE
  parts of the CWA this afternoon; otherwise a dry/rain-free
  first weekend of July for most
* Hot & humid through early next week; max heat index around
  100 in parts of south central PA Saturday/Monday/Tuesday PM
* Best chance of rain/t-storms next Tuesday PM; wetter pattern
  may setup for later next week with eye on moisture from Beryl

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
CAMS guidance and their ensembles show a speckling of showers
developing across Central PA and the Susq Valley this afternoon
as a well-defined pocket of cooler air aloft accompanies a weak cold
frontal passage.

SFC based CAPE values between 500-1000 off the HREF and slightly
higher via the latest, 15Z RAP run indicates that a few of the
showers could grow into low-topped TSRA to the east of the Susq
Mainstem during the mid to late afternoon right along the
cfront.

However, llvl convergence is greatly lacking along the front so
the current, dry forecast looks like the way to go for today.

Best chance (~20%) of a stray PM shower or t-storm will be over
the far southeast zones (ahead of the front) and downwind of
Lake Erie (lake breeze).

Today will be hot and humid with max HX peaking around 100F
across the lower Susq Valley -- where a heat advisory remains in
effect until 8pm. Highs will reach the 80-95F range from NW-SE
which is +5-10F above the historical average for early July at
most sites.

Mainly clear tonight as high pressure builds into the western
part of the Commonwealth. Noticeably less humid air (pwats get
cut in half) will arrive for most of the area with more
comfortable min temps in the upper 50s to mid 60s across the
northwest half of the CWA -- where river/stream valley fog
should develop overnight into early Sunday morning. Conditions
will remain rather muggy/sticky over the lower Susq with lows
around 70F.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Hot temps in the low 80s to low 90s again on Sunday with plenty
of sunshine and slightly reduced/lower humidity. Great pool wx.
Min temps Sunday night look similar to Saturday night with more
fog across the northern tier.

Diurnally driven showers and thunderstorms are possible on
Monday afternoon with easterly/southeasterly flow bringing an
increase of llvl moisture back to central Pennsylvania. The wind
flow and positive moisture flux will signal more clouds and higher
lows Monday night in the 65-75F range (+10-15F above climo).

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As we move into the middle and end of next week, guidance
depicts a pattern of unsettled weather with southwesterly flow
brining moisture associated with Beryl to the area. There does
remain some uncertainty between model solutions with respect to
multiple disturbances throughout the week. Given a relatively
warm and humid airmass throughout the period, diurnally driven
showers and thunderstorms cannot be ruled out during the
afternoon and evening hours.

During this pattern, the best chance of showers/storms will be
attributed with surface low pressure moving north of the area
with an associated cold frontal passage Tuesday evening into
Wednesday morning. Surging PWATs ahead of the frontal passage
will provide ample moisture with enough forcing to produce
locally heavy rainfall across eastern PA, outlined with a
Marginal Risk (level 1/4) in the D4 Excessive Rainfall Outlook
from the Weather Prediction Center.

Despite rainfall chances, relatively warm temperatures are
expected throughout the extended period with Tuesday pushing the
highest heat index values this cycle. A brief cool down in the
wake of the cold front is resolved fairly well in model guidance
into Thursday; however, 500mb heights slightly increasing
towards the end of next week and potentially into the weekend,
outlining a slight warming trend towards the end of the period.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
All airfields will be sct-bkn VFR cu/mdt cu through this
afternoon. Winds during this afternoon could become gusty for a
few hours with gusts likely to be between 15-20kts across the
region until just after sundown. High pressure will be building
in tonight and VFR conditions are expected to persist into
Sunday.

Outlook...

Sun...AM fog possible; otherwise, no sig wx expected with
slightly lower humidity.

Mon...Predominantly VFR w/ no sig wx expected.

Tue-Wed...Scattered showers/storms and restrictions possible.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for PAZ036-056-057-
059-063>066.

&&

$$

SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Lambert/Steinbugl/Banghoff
LONG TERM...Evanego/NPB
AVIATION...Lambert/Evanego/Bowen