Tornado Warning 11, NWS Pittsburgh, PA

Area Forecast Discussion
National Weather Service Pittsburgh PA
413 PM EDT Tue Apr 29 2025

.SYNOPSIS...
A severe weather threat, mainly damaging wind gusts, remains
this afternoon and evening with a convective complex rolling
through. A cold front providing additional showers and storms
crosses overnight. Mostly dry and cooler weather is expected
Wednesday, before another possible round of severe weather on
Thursday.

&&

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

- Severe weather threat, mainly damaging wind, with convective
  complex moving across Ohio
- Additional showers and storms with a crossing cold front
  overnight

-------------------------------------------------------------------

...20Z Update...

A new Severe Thunderstorm Watch has been issued for the
remainder of the CWA. QLCS mow moving across eastern Ohio with
likely wind of 70-80 MPH in spots - have already recorded a 58
MPH gust at ZZV. Special 18Z sounding showed a very favorable
environment downstream, with around 2800 J/kg of surface-based
CAPE and 40 knots of 0-6km shear, suggesting that the complex
will maintain strength well through the region. Widespread and
potentially significant straight-line wind damage will
obviously be the main threat across a wide area, although a
mesovortex tornado or two remains possible as well. Will also
continue to watch convection forming along a Lake-Erie induced
boundary, although so far this activity has not become too
strong as these cells are not remaining discrete and are
competing with each other for inflow.

People in eastern Ohio, northern West Virginia, and southwest
Pennsylvania need to take this event seriously, as these storms
have the potential to create significant damage over a wide
area. Take cover now!

Previous discussion...

Main concern in the near term is the convective complex rolling
across Ohio, and a Severe Thunderstorm Watch is already in
effect for this activity. Main threat with this is damaging
wind, as there have been some measured wind gusts in excess of
60 MPH already. This will be moving into an environment
characterized by 1000-2000 J/kg of surface-based CAPE, as well
as 30-40 knots of deep shear, so maintenance is highly likely.
Recent HRRR runs are catching on to the overall scenario. Some
cells developing in eastern Ohio ahead of the main complex will
need to be watched for some hail potential/low-end tornado
threat if they become superrcelluar. Overall though, hail should
be a lesser threat with marginal mid-level lapse rates. A QLCS
tornado threat remains as well, given sufficient low- level
instability and hodograph curvature.

Additional thunderstorms are expected along the cold front,
which is currently across lower Michigan and will arrive in our
area from the north during the late evening and overnight,
dropping south through the area by sunrise. This activity
should be arriving into worked-over air and present less of a
severe threat, tapering to showers late.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
KEY MESSAGES:

- The front remains south of Pittsburgh Wednesday, with mostly
  dry weather.
- Front returns north Wednesday night with scattered showers
- Increased rain chances Thursday with another severe weather
  chance
-------------------------------------------------------------------

Models now generally push the front fully south of the CWA by
12Z Wednesday, with any shower potential generally confined to
the southeastern ridges. Otherwise, a dry and cooler day is
anticipated. Isolated shower chances may start to lift north
Wednesday night as the boundary returns north as a warm front.

Rain chances increase Thursday into Thursday night as a
shortwave moves up the Ohio Valley ahead of a deepening trough
over the Upper Midwest/Plains. Severe thunderstorms are a
possibility, with the NBM showing 50 percent or greater chance
of 1000 J/kg of CAPE to the southwest of Pittsburgh, and there
appears to be better potential for daytime heating, better than
some scenarios yesterday. Soundings show instability profiles
and shear of sufficient depth to support hail and wind threats
at least on an isolated basis. Temperatures warm back up into
the upper 70s/lower 80s in most spots in the warm sector.

&&

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

- Rain chances continues into Saturday at least
- Uncertainty increases thereafter, with various scenarios
  possible for early next week
-------------------------------------------------------------------

Wet weather continues into Friday and Saturday as additional
shortwaves/the main trough swing through the region. Despite the
moist southwest flow, model ensembles are not too excited about
heavy rain potential; the NBM generally has only 40-50% chance
of greater than 0.50 inch through the 48-hour period ending
Saturday morning.

Models become more uncertain after this time. Some scenarios
sweep the trough through with a period of dry weather following,
while others develop a closed upper low somewhere over the
eastern CONUS. Thus, PoPs/temps remain uncertain, and for now,
will follow NBM suggestions.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
A low-end VFR cu field (cigs around 3-5kft) is developing
across the area as southwest winds gust to 25-30 knots ahead of
an approaching cold front. Showers and thunderstorms currently
over western Ohio are expected to continue eastward, reaching
ZZV between 19z-20z, PIT/AGC between 21z-22z, and LBE/DUJ after
22z. This will be the first wave of storms and carry the
greatest potential for strong wind gusts, hail, and possibly a
brief tornado. Gusts over 55 knots and power outages have
already been reported with these storms over portions of
eastern Indiana.

This first wave will be followed by a brief lull in activity
early this evening until the cold front itself makes its way
into the area after 00z. Another round of showers and storms
will accompany the front, this time moving from NW to SE
reaching FKL/BVI around 01z-03z, PIT/AGC around 03z-05z, and MGW
after 06z. The frontal passage brings an end to convection as
generally light north- northwest winds usher drier air into the
area.

Expect locally lower ceilings and visibilities in and around all
showers and storms. Outside of convection, VFR generally
prevails except for possible MVFR ceilings at MGW starting after
04z and lasting through the frontal passage into early morning
hours on Wednesday. Widespread VFR is expected to return by the
end of the TAF period Wednesday afternoon.

Outlook...
VFR is expected on Wednesday as high pressure briefly builds
in. Occasional restrictions in showers and thunderstorms return
Wednesday night and Thursday as a warm front lifts north.

Showers/storms and restrictions continue Thursday night and Friday
with the approach and passage of a cold front. VFR returns Saturday
under high pressure.

&&

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

&&

SYNOPSIS...Shallenberger
NEAR TERM...CL
SHORT TERM...CL
LONG TERM...CL
AVIATION...Cermak/WM/AK

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
328 PM EDT Tue Apr 29 2025

OHZ039>041-048>050-057>059-068-069-WVZ001>004-012-301930-
Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH-
Muskingum-Guernsey-Belmont-Noble-Monroe-Hancock-Brooke-Ohio-Marshall-
Wetzel-
328 PM EDT Tue Apr 29 2025

...SEVERE THUNDERSTORM WATCH 188 IN EFFECT UNTIL 7 PM EDT THIS
EVENING...

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

.DAY ONE...This afternoon and 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...Wednesday through Monday.

There also is a potential for severe weather on Thursday as well but
confidence is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

PAZ007>009-013>016-020>022-029-031-073>078-301930-
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-
328 PM EDT Tue Apr 29 2025

...SEVERE THUNDERSTORM WATCH 191 IN EFFECT UNTIL 10 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for western Pennsylvania.

.DAY ONE...This afternoon and 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...Wednesday through Monday.

There also is a potential for severe weather on Thursday as well but
confidence is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

WVZ021-509>514-301930-
Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Eastern Preston-Western Tucker-Eastern Tucker-
328 PM EDT Tue Apr 29 2025

...SEVERE THUNDERSTORM WATCH 191 IN EFFECT UNTIL 10 PM EDT THIS
EVENING...

This Hazardous Weather Outlook is for northern West Virginia.

.DAY ONE...This afternoon and 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...Wednesday through Monday.

There also is a potential for severe weather on Thursday as well but
confidence is low at this time.

.SPOTTER INFORMATION STATEMENT...

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

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