Tornado Warning 36, NWS Pittsburgh, PA

Area Forecast Discussion
National Weather Service Pittsburgh PA
415 PM EDT Sun Oct 6 2024

.SYNOPSIS...
Showers and thunderstorms will be possible later this afternoon
and through the evening with a passing cold front. A few of
these storms are expected to be severe. Noticeably cooler
temperatures and dry conditions are expected Monday and through
the work week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
KEY MESSAGES:

- Strong to severe thunderstorms possible later this afternoon
  and into the evening with a frontal passage.
- Cooler temperatures by morning behind the front.
-------------------------------------------------------------------

...2015Z Mesoscale Update...

20Z PBZ special sounding is showing a warm layer at about 800mb
that is capping updraft vertical development. Cumulus field has
formed up in low-level convergence ahead of the front in
northeast Ohio, but to this point, there hasn't been enough
lift to get past that warm layer. Cloud tops are just starting
to cool to -10C on a localized basis along the Lake Erie shore,
so convective initiation may be imminent. The cold front, now
approaching Cleveland, will need to be the main driver of
forcing to take advantage of a supportive environment. For now,
there are no big changes to the expected evolution of
convection going forward, as overall instability/shear are still
in expected ranges.

Previous discussion...

Cold front is currently crossing into far northwestern Ohio, and
shows up well when looking at surface dewpoints. Gusty southwest
flow ahead of this boundary will continue warm and moist
advection into our region. A ribbon of low 60s dewpoints will
move across our region just ahead of the boundary. This will
contribute to MLCAPE values of 500-1000 J/kg and also help to
reduce low-level inhibition. Mid-level lapse rates will steepen
with cooling aloft in an approaching shortwave trough, with
respectable effective shear of 35 to 45 knots. All of this
supports a risk for severe thunderstorms during the period from
late afternoon into mid evening.

Convective initiation near the Lake Erie shore is expected by 4
PM or 5 PM. For the first couple hours, more discrete
supercellular structures are possible given the deep shear, and
a few of these should cross into the northwestern portion of the
CWA through 6 PM. Damaging wind remains the primary threat,
although the shear and lapse rates aloft point to a large hail
threat as well. A threat for a tornado or two exists as well,
although LCLs look to be a bit on the high side and modeled STP
levels are generally below 1.0 for the most part. The window for
this looks brief overall, with the northern CWA having the best
potential.

By 6 or 7 PM, it is expected that convection will take on a bit
more of a linear nature, as low-level shear vectors lean more
towards boundary-parallel. Damaging wind would then become the
primary threat as the line drops through the forecast area into
the evening hours. Storms should begin to weaken by 9 PM or so,
by which time the front should be in the general vicinity of the
Laurel Highlands. The front will have exited the region by 06Z,
taking the last of the frontal precipitation/storms with it.
Clearing should be fairly rapid behind the front, but late
tonight, some clouds and a few isolated showers may return to
areas north of I-80 as the shortwave trough axis moves through.

In the wake of the front, overnight temperatures will fall to
near average.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
KEY MESSAGES:

- Dry weather and much cooler temperatures.
-------------------------------------------------------------------

Any showers north of Pittsburgh should end during the morning
with the departure of the shortwave trough axis. Much cooler
air arrives behind the front for Monday and Tuesday, with a drop
of 15 to 20 degrees from Sunday levels expected. Surface
ridging will extend into the region from an anticyclone dropping
into the middle Mississippi Valley. This surface high will then
extend its influence over the middle and upper Ohio Valley by
midweek, providing dry weather and continued near to below-
normal temperatures. Some very spotty frost potential may exist
both Tuesday and Wednesday mornings, although potential for this
appears higher later in the week.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
KEY MESSAGES:

- Dry weather continues through at least Saturday; light rain
  possible by Sunday.
- Temperatures near to below normal through Thursday before a
  warming trend starts Friday.
- Frost potential in some areas Thursday and Friday mornings.
-------------------------------------------------------------------

High pressure is forecast to persist across the middle and upper
Ohio Valley into at least Saturday, with fairly high confidence as
there is strong ensemble support for that outcome. The troughing
pattern aloft persists into Thursday, with continued near to below-
normal temperatures, before heights rise thereafter lead to a
warming trend for Friday and the weekend. Towards the end of the
forecast period, cluster analysis starts to show some disagreement
with trough/ridge strength and timing,  mainly providing some small
uncertainties in temperatures. However, if troughing does
reestablish by Sunday, there is potential for some light rain thanks
to shortwaves traversing said trough.

Probabilities of morning lows below 37 degrees (representing at
least a threat of patchy frost) are at or above 50% for a good
portion of the area both Thursday and Friday mornings, with some of
the deeper valleys of northern West Virginia likely to experience a
hard freeze.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR conditions will persist at the terminals through at least
20Z as a line of thunderstorms are expected to develop in the
northwest and track southeast.

Scattered to potentially numerous showers and thunderstorms are
favored to develop along the frontal boundary and rapidly move
SE between 21z-04z. Peak intensity of thunderstorms could drop
visibility to 1 mile or less and contain gusty wind in excess of
40kts, but probability of terminal impact for those higher end
values is too low for mention.

Limited moisture ahead/behind front will keep ceiling impacts
short in duration, though notable cold advection should aide in
a stratocu layer developing as it traverses warmer Lake Erie
waters. That said, the NBM probs suggest that visibility and
cigs are not expected to be an issue overnight with the
exception of Tucker County where some fog/low cigs are possible.

.Outlook...
There is a potential (up to 60%) for MVFR stratus reaching as
far south as KPIT in the post-frontal environment early Monday
morning (after 06z) and lingering into the early afternoon.

Otherwise, VFR conditions are highly likely Monday night through
much of the rest of the week under the influence of high
pressure. Cooler temperature and light wind nights may result in
brief periods of morning river valley fog.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

SYNOPSIS...Bookbinder
NEAR TERM...CL
SHORT TERM...CL
LONG TERM...CL
AVIATION...CL

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
459 PM EDT Sun Oct 6 2024

OHZ039>041-049-050-058-059-PAZ007>009-013>016-020>022-029-031-
073>078-WVZ001>004-072100-
Tuscarawas-Carroll-Columbiana-Harrison-Jefferson OH-Guernsey-Belmont-
Mercer-Venango-Forest-Lawrence-Butler-Clarion-Jefferson PA-Beaver-
Allegheny-Armstrong-Washington-Greene-Westmoreland-
Higher Elevations of Westmoreland-Fayette-
Higher Elevations of Fayette-Indiana-Higher Elevations of Indiana-
Hancock-Brooke-Ohio-Marshall-
459 PM EDT Sun Oct 6 2024

...SEVERE THUNDERSTORM WATCH 689 IN EFFECT UNTIL 11 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for east central Ohio, western
Pennsylvania, and northern West Virginia.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

OHZ048-057-068-069-WVZ012-072100-
Coshocton-Muskingum-Noble-Monroe-Wetzel-
459 PM EDT Sun Oct 6 2024

This Hazardous Weather Outlook is for east central Ohio and
northern West Virginia.

.DAY ONE...Tonight.

There is a slight risk of strong to severe storms associated with a
cold front as it crosses the region later this afternoon and through
the evening. Damaging wind, large hail, and possibly a few tornadoes
are the primary threats.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

WVZ021-509>514-072100-
Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Eastern Preston-Western Tucker-Eastern Tucker-
459 PM EDT Sun Oct 6 2024

This Hazardous Weather Outlook is for northern West Virginia.

.DAY ONE...Tonight.

There is a marginal risk of strong to severe storms associated with
a cold front as it crosses the region later this afternoon and
through the evening. Damaging wind, large hail, and possibly a few
tornadoes are the primary threats.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

Preliminary Local Storm Report
National Weather Service Pittsburgh PA
614 PM EDT Sun Oct 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0554 PM     Tstm Wnd Dmg     8 NNE Cooperstown       41.60N 79.80W
10/06/2024                   Venango            PA   911 Call Center

            Tree down on Wallaceville Road.

&&

LL

Preliminary Local Storm Report
National Weather Service Pittsburgh PA
618 PM EDT Sun Oct 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0615 PM     Hail             Mercer                  41.22N 80.23W
10/06/2024  E1.00 Inch       Mercer             PA   Trained Spotter

&&

LL

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