Mechanisms for quasi-stationary behavior in simulated heavy-rain-producing convective systems

Of particular interest are those convective systems that have been observed to occur near mesoscale convective vortices (MCVs) and other midlevel circulations. To simulate the lifting associated with such circulations, a low-level momentum forcing is applied to an initial state that is representative of observed extreme rain events.

The initial vertical wind profile includes a sharp reversal of the vertical wind shear with height, indicative of observed low-level jets. Deep moist convection initiates within the region of mesoscale lifting, and the resulting convective system replicates many of the features of observed systems. The low-level thermodynamic environment is nearly saturated, which is not conducive to the production of a strong surface cold pool; yet the convection quickly organizes into a back-building line.