Bethel Park, Pennsylvania 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

483
FXUS61 KPBZ 041813
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
113 PM EST Wed Dec 4 2024

.SYNOPSIS...
A strong low pressure system will bring winter weather impacts
across the region starting tonight. Snow squalls, strong winds,
and blowing snow are expected Thursday. Lake effect snow is
expected north of Pittsburgh into early Friday. Warmer weather
is expected over the weekend.

&&

.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
KEY MESSAGES:

- Dry and cloudy conditions continue through 5pm this evening
-------------------------------------------------------------

Regional satellite depicts clouds moving into the area with
warm advection aloft in advance of a shortwave. Robust southwest
flow, associated with an approaching low pressure system over
the Midwest, will help boost temperatures west and south of
Pittsburgh 5 to 10 degrees compared to Tuesday.

&&

.SHORT TERM /5 PM THIS AFTERNOON THROUGH FRIDAY/...
KEY MESSAGES:

- Winter headlines remain in effect for portions of the area
  during this time period
- Snow, initially mixed with some rain, begins this
  afternoon/evening
- Gusty winds begin this evening through Thursday
- Intense snow bands/squalls are possible Thursday morning (1am
  to 4am)
- Wind chill values will be below zero in the higher terrain
  early Fri morning
-------------------------------------------------------------------

A deep trough will dig across the Upper Midwest and into the
Great Lakes region on today as a strong surface low crosses
Ontario. Warm advection into the afternoon will boost daily
highs into the mid/upper 30s (though still below average).

As low pressure passes to the north, a cold front will cross the
region late this evening and into the overnight. Initial light
snow showers are possible this afternoon before more widespread
and robust snow showers ahead of and following the front this
evening and overnight. There may be a brief period of wintry
mix with rain for the Pittsburgh metro and locations south
before Arctic air overtakes the region by midnight. Widespread
snow showers and dropping temperatures (by 10 to 15 degrees) are
expected between 7pm to 11pm Wednesday. Snow ratios will
rapidly increase, yielding a transition from wet, heavier snow
to lighter powder by early Thursday morning.

More widespread, synoptic snowfall will wind down after dawn
Thursday morning as winds begin to veer more westerly then
northwesterly. This will turn on the lake effect snow machine
that will persist through much of Friday for the I-80 corridor
and Erie snow belt. Snow storm totals north of I-80 may exceed
10-12 inches (40% probability) in select locations that see
more intense snow bands. A sharp drop-off in totals is expected
to the south of I-80, with locally higher amounts under more
persistent bands Thursday and Friday.

Speaking of snow bands... enhanced instability and steep low-
level lapse rates ahead of and along the front and plunging
temperatures following will allow for an optimal snow squall
setup early Thursday morning. The BTV Snow Squall parameter is
maxed out 10/10 across much of the area from roughly 06-12Z
Thursday. Given timing, intense bands and/or squalls are likely
to impact the morning commute with whiteout conditions, isolated
flash freezing, and locally higher and rapid snowfall
accumulations. Snow Squall Warnings may be needed for drivers
before or during the morning rush hour.

Given a strong pressure gradient with a potentially closed
upper-level low and passing 50-60kt LLJ, gusty winds are
expected to start this evening through Thursday. The potential
peak wind gusts are expected 5pm Wed through 4am Thurs. However,
lingering gusts may continue in the higher terrain due to
mountain wave activity. Advisory level winds are covered with
the Winter Hazard Products for the ridge locations (see next
para.)

Previous watches were upgraded to Warnings or Advisories during
the overnight update. Changes to the snow total forecast were
small, mainly focused on increased totals over the ridges. Given
substantial accumulations expected in the I-80 corridor (60-90%
chance of 6+ inches through the event), a Winter Storm Warning
for Lake Effect Snow was issued for those counties. Lesser snow
is expected south of I-80, and a Winter Weather Advisory was
issued for that tier of counties north of Pittsburgh and south
of I-80. Totals for the ridges are border line Warning/Advisory
criteria, with high probability 6+ inches in the higher
elevations and lower chances elsewhere. Opted for a Winter
Storm Warning for the ridge zones in collaboration with
neighbors given the areas of higher probabilities and potential
for significant snow drifts with strong wind gusts. The
strongest gusts (up to 65 mph) and highest snowfall totals
(6-10") are expected in eastern Tucker County, were a Blizzard
Warning was issued. This will continue through early Friday when
winds and snow begin to diminish.

Snow showers are expected to taper off Friday and Friday night
as the trough exits and flow backs to the SW.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
KEY MESSAGES:

- Snow chances return for the weekend
-------------------------------------------------------------------

There is much higher uncertainty for the weekend, with high
pressure to our south. There is the possibility for another wave
to bring additional precipitation Saturday into Sunday, but
still little agreement on this. However, there is higher
confidence in a more robust system early next week. Regardless,
temperatures will remain below average through the period.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Stratus has filled in across the region quickly ahead of our next
system. CIGs are expected to continue to slowly degrade ahead of
precipitation. Stout warm air advection could kick off precipitation
across the region beginning near/after 20z, with the most widespread
impacts of this first batch of precipitation expected for FKL/DUJ.
This first push of precipitation can bring periods of MVFR
restrictions to terminals but the more widespread restrictions are
expected near/after 00z with steadier snow arriving in the west
first and then pressing east.

IFR conditions are expected at most terminals after 00z and there is
the chance that conditions degrade to LIFR in heavier snow showers.
It remains possible that snow squalls impact area terminals
overnight. Confidence on their occurrence remains high although
confidence on exact placement and timing remains low at this
time. At this time these squalls have been included in PROB30
groups largely focused near/after 06z. These squalls will bring
LIFR conditions to any terminals they impact and the possibility
of VLIFR conditions in the worst squalls.

Windy conditions are expected to persist through the TAF period at
all terminals. Gusts to 30 knots are likely at all terminals and
higher gusts possibly to 35 knots can be observed coincident with
any squalls across the area.

The steadiest snow is expected to wind down outside of FKL/DUJ
largely  after 10z. Northwest flow after this time will keep the
chance to see snow at FKL/DUJ high and there remains a chance that
lingering snow showers cross the region and impact other terminals
after this time.

Outlook...
Improvement to VFR is expected from S-N Friday as the wave
exits and wind backs to the SW. Restriction and snow potential
could linger into Saturday for FKL/DUJ. Otherwise, VFR is
expected to prevail through Sunday before area-wide restrictions
again become possible Monday with rain.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...Lake Effect Snow Warning until 1 PM EST Friday for PAZ007>009-
     015-016.
     Winter Weather Advisory until 7 AM EST Friday for PAZ013-014-
     022-077-078.
     Winter Storm Warning from 7 PM this evening to 7 AM EST Friday
     for PAZ074-076.
OH...None.
WV...Winter Weather Advisory until 7 AM EST Friday for WVZ510-511.
     Winter Storm Warning from 7 PM this evening to 7 AM EST Friday
     for WVZ512-513.
     Blizzard Warning from 7 PM this evening to 7 AM EST Friday for
     WVZ514.

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Hefferan/Rackley
LONG TERM...Hefferan/Rackley
AVIATION...AK