A shortwave moved into the Ozarks area early in the morning on March 21st and sparked convection along a stationary front to the north of the TN Valley. This MCS that originally developed over MO continued eastward along the eastern periphery of an upper level ridge. By the afternoon hours temperatures warmed into the lower 80s with dewpoints in the upper 50s to lower 60s; resulting in an unstable airmass with SBCAPE values upwards of 2,000-2,500 J/kg over northern AL and southern middle TN. 

As the MCS moved into TN it began to interact with the more unstable airmass and intensified over the WFO Nashville CWA. Storms were initially discrete as they strengthened over TN but eventually formed into a cluster near Giles County, TN. During the semi-discrete stage there were multiple reports of golf ball size hail in the Nashville CWA. As the storms moved into Lincoln, TN a strong rear inflow jet developed and was evident on radar. The peak winds evident on HTX radar with this rear inflow jet were upwards of 90kts at the 4,000-7,000 ft level. As the rear inflow jet intensified and surged southeastward there was a tightening of velocity on the northern side of the inflow jet in Moore county. A Tornado Warning was issued as the velocity couplet moved into Franklin county, TN. There wasn’t any verification with the Tornado Warning but widespread tree damage was reported with the strong rear inflow jet.

The storms continued to surge SE into AL and widespread damage continued. Various reports of dime to quarter size hail were reported with the storms. An outflow boundary appeared to have surged out ahead of the line of storms as they moved through northern AL and additional storm development was noted on the western flank of this line. Brief reports of dime to isolated quarter size hail were noted in the Decatur area. Storms continued to move along/just behind the outflow boundary with very limited reports of hail as they exited the Huntsville CWA.