Source: US National Oceanic and Atmospheric Administration
Mesoscale Discussion 0922
NWS Storm Prediction Center Norman OK
1246 PM CDT Wed May 21 2025
Areas affected…parts of eastern Ohio…western
Pennsylvania…northern West Virginia and adjacent western Maryland
Concerning…Severe potential…Watch unlikely
Valid 211746Z – 212015Z
Probability of Watch Issuance…20 percent
SUMMARY…A couple of intensifying storms are possible by 3-5 PM
EDT, perhaps including a supercell or two accompanied by a risk for
severe hail, locally damaging wind gusts, and some potential for a
brief tornado. It is not clear that a severe weather watch is
needed, but trends are being monitored.
DISCUSSION…Ascent and cooling, within the left exit region of a
strong cyclonic mid/upper jet (70+ kt around 500 mb) nosing through
the Ohio Valley, have been contributing to a sustained, broken band
of convection. This has become focused within surface troughing to
the southeast of a modest remnant occluded low now centered over
northwestern Ohio, where the eastward progression of the convection,
to this point, has been outpacing appreciable boundary-layer
destabilization ahead of it.
However, a corridor of relatively stronger surface heating and
destabilization is ongoing where modest boundary layer moisture
lingers across the Allegheny Plateau, across the Pittsburgh PA,
Morgantown and Wheeling WV areas, as far north as the Youngstown OH
vicinity. Latest Rapid Refresh suggests that mixed-layer CAPE may
be in the process of increasing up to around 1000 J/kg within this
corridor, prior to the arrival of the mid-level forcing within the
next hour or two. As this occurs, a couple of developing storms may
undergo substantive intensification, perhaps evolving into
low-topped supercells. This may be accompanied by marginally severe
hail, locally strong surface, and perhaps some risk for a brief
tornado.
..Kerr/Guyer.. 05/21/2025
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…CTP…LWX…PBZ…RLX…CLE…
LAT…LON 40998024 40217953 39327930 39248073 39688093 40518122
41228104 40998024
MOST PROBABLE PEAK TORNADO INTENSITY…UP TO 95 MPH
MOST PROBABLE PEAK WIND GUST…UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE…1.00-1.75 IN