Numerical Simulation and Analysis of Horizontal Convective Rolls and Their Potential Impact on 03 May 1999

A three-dimensional, high-resolution model is employed to investigate the conditions prior to the 03 May 1999 tornado outbreak in order to ascertain if conditions were favorable for the formation of horizontal convective rolls. Horizontal convective rolls (HCRs) are an overlooked meteorological phenomena that may have significant implications on storm initiations in environments from which they develop. In the afternoon and evening of May 3, 1999, a devastating, yet relatively small scale, tornado outbreak occurred across the central and northern potions of Oklahoma and far southern Kansas. Most environmental conditions that existed in this region on 03 May 1999 pointed towards a severe weather outbreak, however, cloud coverage and heating posed major concerns for forecasters. In the smaller scale, it appears that a few conditions existed in the boundary layer in southwest Oklahoma which would be the impetus for what would be an active tornadic day. HCRs may have been one of these smaller scale phenomena that played a significant role in the convective initiation seen on this day. An overview of the conditions that existed on 03 May 1999 as well as an analysis of four idealized HCR simulations employing the ARPS model using conditions from this severe weather event are detailed here.