169
FXUS61 KCTP 031657
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1257 PM EDT Mon Jun 3 2024

.SYNOPSIS...
*Dry for most today and Tuesday with a stray afternoon shower
 or thunderstorm as temperatures and humidity ramp up.
*More widespread rain on Wednesday afternoon and Thursday.
*Cooler this weekend with scattered PM showers/storms.

&&

.NEAR TERM /THROUGH TONIGHT/...
A weak ridge of high pressure at the surface and aloft in Western
and Central PA should keep rain chances at a relative min
(below 15 percent) across that part of the state today. The
western edge of a weak mid level thermal trough dropping south
and brushing our eastern counties could create a few mid to late
afternoon and early evening showers or a brief thunderstorm, but
most of the area should stay dry.

High temperatures this afternoon are on pace to reach the low
80s in the southeast today, but norming cloud cover and a deck
of scattered cumulus/stratocumulus will keep temperatures capped
in the middle 70s at higher elevations in the northern mountains
and Laurels. Expect sky conditions to remain partly cloudy as
fair weather cumulus deck builds this afternoon.

Skies will become clear to partly cloudy tonight with light
wind as the upper level ridge builds overhead and remains there
through Tuesday. A nearly calm wind may promote patchy valley
fog, primarily in the favored deep/river stream valleys of
North Central PA. Another pleasant night to have the windows
cracked as lows drop into the upper 50s to low 60s.

&&

.SHORT TERM /TUESDAY THROUGH THURSDAY/...
Dewpoints will be on the rise Tuesday as southeast flow pumps
moisture-rich air in from the Atlantic. With an upper level
ridge overhead and relatively warm temps aloft (with little
llvl forcing from discernible boundaries), convection should be
spotty and weak Tuesday afternoon. An isolated PM pulse-type
shower/tsra is possible though, as high- level heating promotes
convection developing over the SE facing slopes/ridgetops of
Central PA.

Tuesday will be the warmest day of work week with highs in the
upper 70s to mid 80s and partly to mostly sunny skies. High
clouds will begin streaming in tomorrow afternoon ahead of the
next system, but it will be a pleasant Tuesday for any outdoor
activities.

The next notable chance for rain arrives on Wednesday afternoon
as a low pressure system drifting across the Great Lakes helps
bring surging Gulf Coast moisture into the northeast. Southeast
flow ahead of the approaching low pressure systems sets up a
classic "cool" air damming scenario on Wednesday with persistent
clouds and little to no instability ahead of the approaching
warm advection lift. Temperatures will stay below 80 degrees
everywhere except perhaps far northwest PA and could even
struggle to get much above 70 at higher elevations.

Latest suite of medium range guidance brings the warm front
into southwest PA during the day on Wednesday with stratiform
showers moving in Wednesday afternoon and evening. As mentioned
before, instability will be lacking so not overly concerned
about the severe weather threat on Wednesday evening. WPC has
painted a big Marginal Risk across Central PA with the potential
for some heavier downpours and localized rainfall amounts exceed
1 inch. Not overly concerned about flooding at this point given
dry pattern lately and meager instability, but threat bears
watching as hi-res guidance gets a better handle on the
precipitation distribution and magnitude.

By Thursday morning, most of PA will be in the warm sector, but
without much forcing would not be surprised to see lingering
light showers/drizzle Thursday morning. Cold front will sweep
through sometime on Thursday and could generate a could stronger
showers/storms as it sweeps through. Once the front moves
through, the airmass will noticeably change with lower dewpoints
and cooler temperatures aloft.

&&

.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
The main weather feature for Central PA through next weekend
will be a persistent cold core, upper low centered somewhere
from the eastern Great Lakes region across southern Ontario and
Quebec. As a result, at least hit and miss showers and
thunderstorms are expected on a daily basis, with diurnally more
numerous coverage anticipated in the afternoon and early evening
hours, particularly for the northern tier of the Commonwealth.

Current indications are that by early next week, the upper low
should begin to fill and drift northeast, with showers and
storms becoming less prevalent over time.

Temperatures are likely to average somewhat below climatology
for early to mid-June, with daily highs in the upper 60s and
70s, and overnight lows in the 50s to lower 60s.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Looking at MVFR and IFR conditions over portions of the
mountains this morning.

There is still a small chance of a shower or storm later this
afternoon, but little activity occurred on Sunday. Thus hard to
see any today or on Tuesday either.

Main thing will be low CIGS and a bit of fog this morning
across the western mountains. UNV and AOO, and also IPT are
less likely to to have fog, but MVFR CIGS at times will prevail
at these sites. Sites like MDT and LNS are likely to remain VFR.

For late Monday night and early Tuesday morning, lower
conditions will be possible again.

Earlier discussion below.

Rain showers should be east of the central PA airspace by 5-6Z
as forcing wanes. MVFR ceilings will continue for the western
airfields and develop farther east into UNV/AOO/IPT later this
evening through tonight. Fog and IFR Ceilings will be possible
late tonight/early Monday morning for these same spots as
westerly flow results in upslope and stratus development.

Sunrise will bring an improvement to sub-VFR conditions at the
central and eastern terminals. However, the western sites will
take a couple of hours to rise to MVFR then finally VFR. The
instability and left over moisture could spark a SHRA or two
Monday afternoon, but coverage is not expected to be enough to
warrant mention for any site. There is the possibility (15-20%)
for a TSRA at MDT/LNS/IPT in the afternoon, but again have kept
mention out given the low probability at this time.

Outlook...

Tue...AM fog/IFR possible SE. Otherwise, no sig wx.
Wed...Sct SHRA/TSRA with restrictions possible PM.
Wed night-Thurs...CFROPA with numerous SHRA/TSRA. Flight
restrictions likely (70%). IFR possible (30%).
Friday...AM fog poss, sct PM SHRA/TSRA.

&&

.CLIMATE...
Prelim May and Spring 2024 Temperature & Precipitation Rankings

Harrisburg: T12th warmest; 76th driest May
 T3rd warmest; 33rd wettest Spring

Williamsport: 9th warmest; 22nd wettest May
4th warmest; 11th wettest Spring

Altoona: 9th warmest; 13th wettest May
2nd warmest; 3rd wettest Spring

Bradford: 4th warmest; 36th driest May
Warmest; 21st wettest Spring

&&

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

&&

$$

SYNOPSIS...Banghoff
NEAR TERM...Lambert/Banghoff
SHORT TERM...Lambert/Banghoff
LONG TERM...Jurewicz
AVIATION...Martin
CLIMATE...Steinbugl