912
FXUS61 KCTP 031645
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1245 PM EDT Fri May 3 2024

.SYNOPSIS...
-Scattered showers and thunderstorms will begin this afternoon
 mainly in western PA as clouds increase
-Noticeable cool down over the weekend with overcast skies and
 periods of rain
-Remaining unsettled next week with a gradual warming trend

&&

.NEAR TERM /THROUGH TONIGHT/...
The early afternoon hours will remain partly cloudy before
increaing cloud cover into the early evening. High pressure
channeling down the eastern slopes of the Appalachians will
maintain dry wx over the majority of the CWA (eastern 2/3)
through 00Z Sat with max POPs to the west of the US219 corridor.
This area should be in the warm sector where the most unstable
air will reside. A couple of locally heavy t-storm downpours
could produce spot amounts >1" on the west aspect of the
Allegheny Plateau near the edge of higher pwat air surging in
from the upper OH Valley. The WPC D1 ERO covers this area, with
the greatest threat just outside of our CWA (over PBZ) based on
the latest 03/12Z HREF guidance. The 24hr maxTchange will be
considerably cooler over the central and southeastern
ridge/valley region this afternoon with fcst highs giving back
7-15 degrees from yesterdays record challenging to record
breaking temps.

Shower activity should eventually expand west to east through
tonight with a surface boundary stalling out over far western
PA. An increasingly moist east/southeast flow brings widespread
low clouds and perhaps some fog/mist on the ridgetops. The
potential for not severe t-storms remains low given the lack of
instability and the increasing low level stable air with the CAD
setup. Low temps will be above early May climo and range
between 45-55F from the southwestern Poconos/Coal Region to
Warren County.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Hires models show CAD pattern firmly entrenched over CPA on
Saturday, and therefore we continued to trim max temps vs. NBM.
The current thinking is most areas will remain in the mid to low
50s given the easterly flow. No risk of thunder on Saturday so
removed from wx grids and changed character of precip to rain
from showers.

No major changes to the Sunday fcst were made other than
increasing rain PoPs through early Sunday morning. Rain/showers
continue through Sunday and into Sunday night with highs
recovering 5-10F over the southwest 1/2 of the CWA. Some
isolated convection is possible in this area Sunday PM as the
warm sector shifts to the east. Despite the relatively high
moisture availability, limited rain rates should keep blended
mean QPF btwn 0.50-1.00 inches ending 00Z Monday. Fcst lows
Sunday night will be +10-15F above climo for early May in the
50-60F range.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
The extended period will trend milder and remain unsettled with
several chances for rain. A cold front will stall near or south
of the MD line Monday and Tuesday before lifting to the
northeast (as a warm front) into midweek. The favors the best
chance for rain the SW zones on Monday before POPs increase to
50-70% Tuesday into Wednesday. After a weekend cooldown, temps
will trend warmer/back above climo into the 70s to low 80s.

With several chances for rain next week along with persistent
mild temperatures, green up should rapidly expand into northern
PA thus ending the spring fire weather season. Additionally,
there is no chance for frost or freeze conditions through the
end of the week.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR/unrestricted conditions should remain in place across
central PA terminal sites into this evening. Confidence on this
scenario is fairly high (70-90%).

An area of showers could reach the Allegheny Highlands late in
the day (as early as 21-22z) and perhaps bring fuel alternate-
MVFR restrictions at KJST and KBFD. The threat for MVFR cigs
then increases substantially between 22z Fri and 02z Sat across
the Laurels and Alleghenies, including JST, BFD, AOO, and UNV.

Conds will continue to deteriorate Fri night into early Sat
morning as southeast onshore flow advects cooler, moist air from
the North Atlantic. IFR cigs are likely (60 percent chance or
higher) for most TAF sites by 12z Sat, with the exception of
IPT.

Light surface winds will increase out of the SE to 5-10 kt
Friday. Occasional gusts of around 20 kt could occur in the
afternoon. Southeast flow will continue into Saturday.

Outlook...

Sat-Sun...Widespread restrictions due to low cigs. SHRA likely
with a chance of TSRA.

Mon-Tues...AM fog/clouds poss. PM -SHRA possible areawide.

&&

.CLIMATE...
Several records were tied or set on Thursday May 2nd:
SITE       OBSERVED TEMP      PREVIOUS RECORD
Altoona         87F             87 in 1954
Harrisburg      90F             88 in 1913
State College   ??*             86 in 1938
Williamsport    89F             89 in 2018

*Official report from State College will be available Friday
 morning.

May 2nd was also the first 90F day at Harrisburg. It is the
13th earliest 90F day on record. The earliest 90F day occurred
on April 17th in 1896 and 2002. The average first 90F day is
June 1st.

&&

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

&&

$$

SYNOPSIS...Steinbugl/Bowen
NEAR TERM...Steinbugl/Bowen
SHORT TERM...Steinbugl/Bowen
LONG TERM...Steinbugl/Banghoff
AVIATION...Jurewicz/Colbert
CLIMATE...Steinbugl/Banghoff