SPC Mesoscale Discussion: Severe Potential… Watch Possible

SUMMARY…Long-lived thunderstorm cluster continues to move across east-central Arkansas this morning. Additional thunderstorms to the east, across northeast Mississippi and northern Alabama, continue to increase in intensity and coverage. Hail and gusty winds will be possible with both clusters of thunderstorms. Trends will be monitored for a potential Severe Thunderstorm Watch.

DISCUSSION…Long-lived quasi-linear convective system (QLCS) continues to maintain its intensity, or even slightly strengthen, this morning as it moves along and south of I40 in eastern Arkansas. Additionally, to the east of this cluster of thunderstorms, another cluster of thunderstorms continues to slowly intensify and increase in coverage this morning across northeast Mississippi and northern Alabama. The QLCS across Arkansas continues to be fed by lower-tropospheric theta-e advection as it traverses along the cool side of the theta-e gradient, Farther east, the theta-e gradient becomes more diffuse, with the ongoing thunderstorms across northeast Mississippi and northern Alabama being in a relative theta-e minimum. Considerable uncertainty remains with how these two distinct areas of convection will interact and evolve this morning. Overnight thinking was that the QLCS would eventually weaken this morning and thunderstorms farther east would develop later. However, observations hint at the development of a mesocale convective vortex within the parent mesoscale convective system across Arkansas. This would suggest the QLCS may persist through the morning and into the afternoon. This idea is supported by the latest HRRR runs. Isolated large hail and strong thunderstorm wind gusts would be the primary threat. The thunderstorm cluster to the east of the QLCS is likely being aided by warm-air advection, which may result in an isolated severe hail or wind report, but the activity may decrease in intensity later this morning as warm-air advection weakens. However if the ongoing thunderstorms can develop a cold pool, they may become better organized allowing them to persist into the afternoon and pose a longer hail/wind threat. Given the uncertainty in spatio-temporal evolution of the organized severe threat, trends will continue to be monitored for possible watch issuance.

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