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000
FXUS61 KCTP 081800
AFDCTP

Area Forecast Discussion
National Weather Service State College PA
200 PM EDT Thu Jun 8 2023

.SYNOPSIS...
Smoke from Canadian wildfires will cause poor to unhealthy air
quality today, but the visibility will gradually improve from
north to south during the afternoon. Hazy skies will become
partly to mostly cloudy with a few rain showers focused over the
northwest half central PA this afternoon. Temperatures will
trend modestly cooler today and tomorrow with an uptick in
shower activity expected Friday afternoon. A warmup over the
weekend will likely precede much needed rainfall early next
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Latest HREF shows the area of dual to multi-layered strato/alto
cu clouds covering roughly the NW half to 2/3rds of PA late this
morning, with mostly sunny skies over the south.

As the leading edge of the clouds drift south this afternoon,
vertical mixing and a few hundred J/KG will poke some holes in
the cloud deck and grow isolated to scattered showers over the
south and sctd to numerous showers across the north. The cape
will be quite thin and located mainly below 15 KFT AGL where the
EQL temp will be only -18C.

So expect QPF with the showers to be quite light (just a few to
several hundredths in most places receiving the rain).

Code RED/Orange Air Quality Alert (AQA) splitting the state from
east to west today (issued by PADEP) - Unhealthy for most
individuals in the Eastern Half of the State, and impacting
mainly sensitive groups to the particulate/smoke pollution in
the Orange area across the western half of the state. Vsbys
should improve by a few miles in most places this afternoon as
the HRRR shows the near sfc smoke concentrations becoming more
fractured and under 100 ug/m3 in many locations.

After the very chilly morning with scattered frost across the
northern half of the CWA, the timing of the cloud cover drifting
south has greatly capped off warming across the north with 16Z
temps only in the 50s to low 60s in many places, with mid 60s to
low 70s in the south.

Shower activity should wane with the loss of heating into
tonight with another relatively cool overnight period with below
climo minimum temps in the 40-55F range.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
08/00Z model and ensemble guidance shows the main shortwave
trough axis rotating through CPA on Friday and the entire
mid/upper trough lifting out of the Northeast on Saturday.
The best moisture/lift/instability combination should spell
greater coverage of diurnal convection Friday afternoon which
is reflected in the NBM PPI.

RAP smoke model indicates the highest concentrations of near-
sfc smoke will be south of the area on Friday and this should
lead to improving air quality/visibility (not as hazy).

Can`t rule out an isolated shower/t-storm over the northeast
quad of CWA Saturday afternoon, but rising heights and warming
aloft point toward a mainly dry and warmer start to the second
weekend of June. Max temps trend +10F day over day with highs
back to seasonal levels in the 70-80F range. Milder trend
continues through Saturday night with lows in the upper 40s to
mid 50s.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The various ensemble prediction systems remain consistent in
their depiction of the large-scale pattern heading into the
weekend and early next week. The pattern will consist of a low
amplitude upper trough axis across eastern Canada and the
northeastern CONUS, with an upper ridge axis holding firm over
the middle of the CONUS and central Canada. Resultant NW flow
aloft will keep any sustained heat well west of the Commonwealth,
with a progressive surface cold front likely to cross the
region Monday. The timing on this frontal passage has been
inconsistent between model runs, but the most recent guidance
suggests Monday afternoon. However, transition from current
blocking pattern is still not fully certain, and so what we can
say for sure is that Sunday into Monday may present the best
CHANCE of rain we`ll see for the next week, but it`s far from
certain at this early time.

As for the daily sensible weather, temperatures next week should
remain seasonal for the end of spring and the beginning of
summer. Scattered showers and thunderstorms remain possible
Tuesday and Wednesday afternoon in association with diurnal
heating and a weak upper level shortwave, but dry conditions are
expected to be prevailing through most of next week.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Smoke from the Canadian wildfires will continue to affect the
airspace this Thursday afternoon. Widespread MVFR conds (either
with smoke (mainly across the Lower Susq) and or strato cu
clouds/HZ over the Central and Northern parts of the state.

Guidance suggests visibility conditions will slightly improve
throughout the afternoon hours, although haze/smoke effects
will likely continue to bring MVFR visibilities over the Lower
Susq Region. Improving smoke conditions could bring
predominately VFR skies back by Friday evening into Saturday.

There is still a chance that rain showers will make way into
the northwestern airfields, although very limited TS mention as
confidence is low with minimal deep layer instability/vertical
motion at this time. Haze looks likely to continue into the
evening and overnight hours across all of central PA.

Outlook...

Thu-Fri...Possible PM TSRA. MVFR Vsbys in smoke with localized
IFR vsbys possible, mainly on Thursday.

Sat...No sig wx expected.

Sun...Slight chance of PM SHRA and TSRA.

Mon...Higher likelihood of SHRA and TSRA, especially PM.

&&

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

&&

$$
SYNOPSIS...Lambert/Steinbugl
NEAR TERM...Lambert/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...Travis/Bowen
AVIATION...NPB/Bowen