Mesoscale Discussion 1383
NWS Storm Prediction Center Norman OK
1242 PM CDT Sun Jun 23 2024
Areas affected...Portions of the Ohio River Valley into southern New
York
Concerning...Severe potential...Watch likely
Valid 231742Z - 231945Z
Probability of Watch Issuance...80 percent
SUMMARY...Severe storm risk will gradually increase through the
afternoon, with damaging winds being the primary concern. A watch
will likely be issued for parts of the area in the next few hours.
DISCUSSION...Ahead of a northeast/southwest-oriented cold front
draped across the OH River Valley, a corridor of upper 60s to lower
70s dewpoints and pockets of heating will contribute to moderate
surface-based instability -- despite poor midlevel lapse rates
sampled by 12Z observed soundings. As modest midlevel height falls
overspread the region, surface-based thunderstorms should gradually
increase in coverage along/ahead of the cold front.
Storms should slowly increase in intensity as they track eastward
and intercept the destabilizing warm/moist sector. Given ample
deep-layer westerly flow/shear (around 35-kt effective shear)
roughly perpendicular to the front, a mix of loosely organized
clusters and transient supercells are expected. Steepening low-level
lapse rates and the enhanced low/midlevel flow will favor locally
damaging gusts as the primary concern, especially with any localized
upscale growth. However, marginally severe hail and a tornado or two
cannot be ruled out, especially with any sustained semi-discrete
supercells. A watch (potentially two separate watches) will likely
be issued for parts of the area in the next few hours.