Precipitation falling from an area of convective rolls was observed by the CASA radar network between 12 UTC and 13 UTC during the morning of April 24, 2007. The rolls were aligned with the mean wind in the boundary layer, southwest to northeast, were spaced approximately 2 km apart and extended 20 to 30 km in length. The rolls extended up to 5 km AGL. From the radar data it appears the rolls moved to the northeast and dissipated. Approximately 2 hours after the convective rolls appeared to have dissipated, an area of strong convection developed and moved through the CASA network, following the path of the antecedent convective rolls.

This study documents the appearance and morphology of the rolls in the radar data and investigates the impact of their vertical circulation and precipitation on the initiation and track of the subsequent convection. The ARPS (Advanced Regional Prediction System) Data Analysis System (ADAS) is used to assimilate in situ and CASA and NEXRAD radar observations to quantify the impact of the convective rolls on the atmospheric state. Short-term (2-hour) mesoscale forecasts from ARPS are run to quantify the impact of the convective rolls on the subsequent convection forcing. This study will indicate whether high temporal and spatial observations, as available from CASA, could improve analysis and prediction of mesoscale convective development in similar cases.