342
FXUS61 KCTP 301459
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
1059 AM EDT Tue Apr 30 2024

.SYNOPSIS...
-Summerlike to close out April with showers and a few t-storms
-Dry weather with lower humidity Wednesday through Thursday
-Trending unsettled into the weekend with rain likely Sat/Sun

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
1050AM/1450UTC: Minor adjustments to hourly temps and POPs based
on the latest radar and satellite trends. Added a few degrees to
max temps and added +RW to wx grid in the MRGL risk ERO area
which has been scaled back to only include the northeastern
counties adjacent to BGM/PHI. Latest hires guidance keeps
heaviest rain closer to the Catskills and in the Poconos this
afternoon with quick moving storms maintaining low flood risk.

Previous Discussion Issued: 454 AM EDT Tue Apr 30 2024

Low level theta-E ridge axis and moderate amount of llvl
moisture convergence along its western edge and near a sfc
quasi-stnry boundary that`s sagged into Ncent PA will bring the
chance for a few isolated SHRA/TSRA near and to the north of the
KIPT area through the mid morning.

A cold front moving through Ohio this morning will reach the
Western Mtns of PA late this afternoon. Target periods for the
best chance of showers (and isolated TSRA) will be between 11 Am
and 4 Pm across the Northwest Mountains, during the mid
afternoon to early evening over the Laurel Highlands, Central
Mountains and the Susquehanna`s West Branch Valley, and during
the late afternoon through the evening over the Middle and Lower
Susquehanna Valley.

Fairly thin CAPE today with Equil Levels between about 26-28 KFT
AGL will support some isolated to scattered embedded TSRA
capable of producing a quick one half inch of rainfall, small
hail and brief gusty winds of 40 to 50 mph.

Severe threat appears low with any decent amount of shear
confined to the lowest 0.5 KM agl and unidirectional flow with
very little speed shear aloft. Best chance (albeit only around
50 percent) to exceed 1000 J/KG of SFC based CAPE per the 30/03z
SREF will be across Lancaster County early this evening, while
the greatest LLVL directional and speed shear will be found to
the north of the KIPT area in the vicinity of a 1010mb sfc low
forming along a lee trough with PWAT values between 1-1.25
inches.

With their latest update, WPC trimmed their MRGL risk area for
Excessive Rain to cover just the northern half of PA today/this
evening. Forecast QPF today into early tonight varies from
around 1.00 inch across Sullivan County in our NE and perhaps
less than 0.10 throughout some of our South-Central Valleys

Morning showers and mid to late afternoon passage of the
aforementioned cold front will yield the coolest high temps
today acrs the NW Mtns, where temps could be capped off in the
upper 60s. In Contrast, the Middle and Lower Susq Valley will
heat up nicely into the low and mid 80s, under just some cirrus
for the bulk of the day with showers generally after 19 or 20Z.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Diminishing showers are expected from west to east tonight, as
the shortwave traverses the state. Latest guidance points to
fair weather for most if not all of the forecast area Wednesday,
as surface ridging and much drier air work into the state
behind the exiting shortwave. Mixing down forecast 850mb temps
of around 11C yields expected highs in the 70s Wednesday. We
have leaned toward the lower NBM10pct dewpoints Wed afternoon
based on dry air above a weak inversion in the model soundings.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Upper level ridging building over the region should ensure fair
and warm conditions Wed night through at least early Friday.
High pressure tracking north of PA into the Canadian Maritimes
will then result in a developing easterly flow and the onset of
cooler conditions Friday PM into next weekend. All medium range
guidance points to a rainy and cool weekend, especially the
first half, as a southerly low level jet linked to an upper
trough over the Grt Lks and an associated plume of deep moisture
overruns a stationary front over the Ohio Valley. Latest EPS
plumes indicate around a half inch of rain is likely by late
Sunday. Passage of the upper trough and associated occluded
front appears likely to bring drier and warmer conditions by
Monday of next week.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR conditions will continue for at least the next few hours. A
cold front approaching from the west will slowly track
through Central PA through the day and will bring showers and
thunderstorms to the region. As the showers and storms move in,
ceilings will gradually lower to MVFR and brief visibility
restrictions will be possible in any heavier thunderstorms.

After the front passes, low clouds will linger into the
overnight hours, especially over the western mtns (JST/BFD).
These should diminish in the early morning on Wednesday. We
could see some fog develop overnight and into Wednesday
morning, especially in any locations that see some breaks in the
clouds behind the front. Currently, the HREF and SREF show a
30-50% chance of IFR visibilities developing after 06Z across
the western mountains.

Outlook...

Wed...Early AM low cigs possible W Mtns.

Thu...No sig wx expected.

Fri...Evening showers/cig reductions possible.

Sat...Widespread SHRA/TSRA. IFR poss.

&&

.CLIMATE...
Record high temperatures were set at the following locations
today (Monday):

SITE        2024 OBS     PRVS RECORD
Altoona          86F     83F (1956)
Bradford         82F     76F (1984)
Williamsport     89F     86F (1942/1974)

&&

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

&&

$$

SYNOPSIS...Steinbugl
NEAR TERM...Lambert/Fitzgerald/Steinbugl
SHORT TERM...Lambert/Fitzgerald
LONG TERM...Fitzgerald
AVIATION...Dangelo/Bauco
CLIMATE...Banghoff/Colbert