Mesoscale Discussion 0650
NWS Storm Prediction Center Norman OK
1241 PM CDT Mon May 06 2024
Areas affected...Parts of the Tennessee River Valley/southern
Appalachians
Concerning...Severe potential...Watch unlikely
Valid 061741Z - 061945Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorm development is expected along a residual
outflow boundary and in the vicinity of an MCV across portions of
the Tennessee River Valley. A couple of strong to severe storms are
possible with an attendant risk of large hail and damaging gusts.
DISCUSSION...17 UTC surface observations and visible imagery show
gradual cumulus development and a few initial weak thunderstorms
within a destabilizing air mass in the wake of early-morning
convection. Higher theta-e air (characterized by temperatures in the
upper 70s with dewpoints in the upper 60s/low 70s) is supporting
MLCAPE values upwards of 1500 J/kg as it slowly spreads north ahead
of a meandering MCV over the lower OH River Valley. Continued
daytime heating through broken cloud cover should promote further destabilization and reduction of lingering MLCIN, making more robust
convective initiation ahead of the MCV probable during the 18-20 UTC
period. Despite weak low-level winds, enhanced 30-40 knot mid-level
winds along the southern periphery of the MCV should sufficiently
elongate hodographs to support storm organization, including the
potential for a supercell or two. Consequently, large hail appears
possible with the more robust/mature cells along with a low-end
tornado threat given some veering of the low-level wind profile.
Scattered thunderstorm development may promote upscale growth into
clusters through late afternoon with an attendant increase in
damaging wind potential. This threat is expected to remain somewhat
confined close to the MCV as it migrates east, which should limit
the overall coverage of the threat. Watch issuance appears unlikely
at this time.