626
FXUS61 KCTP 021633
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1233 PM EDT Sun Jun 2 2024

.SYNOPSIS...
A southwesterly flow of increasingly moist air ahead of
weak low pressure over the Great Lakes region will bring
showers today across the Western Mountains of the state with
scattered mid to late afternoon showers possible across the
Central Mountains and Susquehanna Valley.

It will turn warmer with moderate humidity Monday and Tuesday
along with an isolated shower or thunderstorm possible in the
afternoon and evening.

A slow moving cold front will cross the region during the
middle of the week bringing the best chance for rain/storms,
then an upper level trough will build over the region late week
into next weekend with more unsettled weather expected.

&&

.NEAR TERM /THROUGH TONIGHT/...
Clouds will gradually thicken up and lower to under 8 KFT AGL
across the Western Mtns late this morning, across the Central
Mtns early this afternoon, and east of the Susq Valley late in
the afternoon/early this evening. PWATS will rise from 0.5 to
0.7 inches this morning to between 1.25 and 1.5 inches this
afternoon. As such, rain showing up on radar may not necessarily
equate to rain reaching the ground through the morning hours.

Additionally, very little low level convergence is present
within the warm sector spread across our region, nor is there
any significant larger scale deep layer forcing beneath the
favorable quads of a jet. As such, precipitation amounts should
be light. HREF 12 hour amounts ending at 00Z or 06Z Monday are
generally under 0.10" with a few spotty 0.20" + amounts possible
across Central and Western PA. MU CAPE is mainly under 250 J/KG
later today and tonight, however, 925-850 mb based LIs are
about -1C over Southern PA from 22Z today to 05Z Sunday. So a
rumble of thunder can`t be ruled out from isolated/embedded low-
topped TSRA.

High temps this afternoon (before any -SHRA move in from the
west) will vary from the upper 60s to low 70s across the higher
terrain of Northern and Western PA. to around 80 in the
Southeast. Surging dewpoints overnight will be a sign of more
moisture in the air. For locations that get precipitation today
and see some clearing overnight, patchy fog will be possible.
Low confidence in fog coverage based on uncertainty with
overnight cloud cover, but can`t rule out some instances of
valley fog on Monday morning. Lows will range from the mid 50s
in the northwest to low 60s southeast.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
A very weak cold frontal boundary will push south across the
state early in the period before washing out as it nears the
Mason/Dixon line on Monday.

Building upper level ridge to 580dm should favor lower POPs
Mon-Tue. However, the airmass will be trending warmer and more
humid with just a bubble of weak sfc high pressure drifting from
Lake Ontario on Monday to the New England Coast by early
Tuesday. As a result, we can`t rule out spotty diurnally driven
convection. Have gone with isolated wording for shower/storm
potential as pinning down the exact location of storms is
difficult in this type of pattern.

High temps both Monday and Tuesday will range from the mid 70s
across the highest elevations of the North and West to the low-
mid 80s in the Southern Valleys.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Falling heights and surging pwats ahead of a deepening upper
level trough over the Grt Lks should result in showery weather
Wednesday and Thursday. At the surface, latest medium range
guidance shows a surface high parked along the New England
coast, which will likely keep Central and Eastern PA relatively
stable, with a limited risk of severe weather. The most
concentrated showers and possible tsra should come with the
passage of the low level jet just ahead of the cold/occluded
front passage Wed PM into early Thursday. Ensemble plumes
suggest most likely areal average rainfall Wed-Thu is around
a half inch.

Latest GEFS and EPS indicate drier weather Friday/Saturday, as
the low level jet/plume of highest pwats shift east of PA with
the exiting cold/occluded front. However, scattered, diurnally-
driven showers appear probable, especially over the NW Mtns,
associated with the deep upper trough/closed low parked over the
Grt Lks.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Mid and high clouds thickening up, but barely any rain, and not
flight restrictions, are occurring as of yet over the airspace
of central PA. DUJ and IDI are into MVFR right now (16Z), but
not any farther east. As we moisten up, a brief reduction into
MVFR is possible before sunset over the west (BFD, JST). Some
fog and lower CIGS will be possible late, mainly across the
west. However, without much rainfall, it would be northwest flow
just aloft and the resultant upslope that might create lowered
cigs/vis overnight. Will keep mentions rather tame (higher-end
IFR) without tanking them (V/LIFR).

Outlook...

Mon...Patchy AM fog, slight chance of PM t-storms.

Tue-Thu...SHRA and TSRA at times with restrictions possible.

&&

.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...Lambert
NEAR TERM...Lambert/Banghoff
SHORT TERM...Lambert
LONG TERM...Fitzgerald/NPB
AVIATION...Dangelo/Martin
CLIMATE...Steinbugl