698
FXUS61 KCTP 302138
AFDCTP

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

.SYNOPSIS...
-Closing out April with showers and a few strong t-storms
-Warm/dry weather with lower humidity Wednesday-Thursday
-Trending unsettled into the weekend with rain likely Sat/Sun

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
235PM/1835UTC: Latest SPC mesoanalysis page shows the best
MLCAPE ribbon from the northeastern-most CPA zones northward
through the Poconos to KBGM. A few storms in Tioga and Sullivan
County have cores worthy of SPS at this time. The storm in
Susquehanna County (WFO BGM) remains the storm of the day so
far in PA.

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.

Marginal severe/FF risk ends this evening with loss of heating.
Hires ensemble data shifts showers into the southeastern part of
the area tonight before gradually diminishing/moving eastward
through early AM Wednesday.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Latest guidance continues to indicate warm/dry conditions
through midweek with a trend toward unsettled weather into the
weekend.

Dry air entrainment/mixing heights combined with mostly sunny
skies and mean westerly flow all signal to cut dewpoints and
raise temps by a few degrees in-kind for both afternoons.

The sfc pattern by Friday begins to take on a CAD configuration
as high pressure channels down the eastside of the Appalachians.
Can`t rule out a late-day PM shower or t-storm across the
western Alleghenies with POPs increasing from west to east
Friday night into Saturday morning. Cloud trends and southeast
flow could result in a considerable west/east temp gradient
with max temp spread between 80-65F across central PA. Further
adjustments to Friday high temp fcst likely over the next few
cycles. This setup could also favor low clouds and fog into the
middle and lower Susquehanna Valley Friday night into AM Sat.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
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 /22Z TUESDAY THROUGH SUNDAY/...
A cold front is crossing central PA this evening, accompanied
by scattered showers and storms. While predominantly VFR conds
were found, this activity is causing brief vsby reductions.
Additionally, there could be a period of MVFR cigs across the
western highlands (JST, BFD) with the upslope flow behind the
front this evening.

It may take some time to get the lingering showers out of the
Lower Susq Valley (MDT, LNS) overnight. Otherwise, as skies
begin to clear from west to east and winds diminish, we will
have to watch for fog formation during the pre-dawn hours.

We will see improvement areawide Wed morning, as any lingering
fog dissipates and leave mostly sunny skies and VFR conds with
a W/NW sfc breeze of 5-10 kts.

Outlook...

Thu-Fri AM...No sig wx expected.

Fri PM-Sat...Scattered SHRA/TSRA developing from west to east w/
reductions possible.

Sat night-Sun...Widespread SHRA/TSRA expected.

&&

.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...Steinbugl
LONG TERM...Fitzgerald/Gartner
AVIATION...Gartner/Evanego
CLIMATE...Banghoff/Colbert