Structure and evolution of numerically simulated squall lines

We find that the simulated squall lines are most sensitive to the magnitude of the component of shear perpendicular to the line, and that we may reproduce much of the range of observed structures by varying this single parameter. For weak shear, a line of initially upright-to-downshear-tilted short-lived cells quickly tilts upshear, producing a wide band of weaker cells extending behind the surface outflow boundary. For moderate-to-strong shear, the circulation remains upright-to-downshear tilted for longer periods of time, with vigorous, short-lived cells confined to a relatively narrow band along the system's leading edge. At later times, however, these systems may also weaken as the circulation tilts upshear. -from Authors