882
FXUS61 KCTP 301824
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
224 PM EDT Tue Apr 30 2024

.SYNOPSIS...
-Closing out April with showers and a few strong 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/...
135PM/1735UTC: Updates for the rest of the afternoon include:

1) Upgrade to MRGL risk SWO (level 1 out of 5)
Strong daytime heating is occurring over areas from central NY
into central PA, where dewpoints are in the upper 50s. Forecast
soundings suggest afternoon MLCAPE values of 500-1000 J/kg,
leading to scattered afternoon thunderstorms. Low-level winds
are relatively weak/veered, but sufficient winds aloft and steep
low-level lapse rates could contribute to a risk of gusty/damaging
wind gusts and hail in the strongest cells this afternoon. 5%
severe wind and hail probs. Updated wx grids and HWO.

SWOMCD #573: Concerning...Severe potential...Watch unlikely

Probability of Watch Issuance...20 percent

SUMMARY...Intensifying thunderstorms, possibly
including a gradually organizing cluster, may pose increasing
potential for marginally severe hail and wind by 2-4 PM EDT. It
is still not clear that a severe weather watch will be needed,
but trends will continue to be monitored.

2) MRGL risk WPC ERO trimmed back to northeast zones adjacent to
BGM and PHI: Latest hires guidance keeps heaviest rain closer
to the Catskills and in the Poconos this afternoon with brief
heavy downpours form quick moving storms maintaining low flood
risk.

17-18Z temps are likely near max values for today and have
outperformed a bit to the upside given strong daytime heating.
GOES16 Geocolor visible satellite shows most of central PA now
covered under expanding cumulus which should cap further upside.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
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 /FRIDAY NIGHT THROUGH MONDAY/...
High pressure tracking north of PA into the Canadian Maritimes
will likely result in a developing easterly flow and the onset
of cooler conditions Friday PM into the 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 Great Lakes 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. A warm front arriving Tuesday could signal a return
of clouds and showers/tstorms to the region.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A cold front approaching from the west will slowly track
through the Central PA airspace 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 and Sun...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...Steinbugl
SHORT TERM...Lambert/Fitzgerald
LONG TERM...Fitzgerald/Gartner
AVIATION...Gartner/Bauco
CLIMATE...Banghoff/Colbert