Initiation and modulation of severe storms along warm fronts

Warm fronts constitute a major forcing and organization mechanism for severe spring weather, particularly in the Midwest. Besides the role of frontal lifting in aiding convective initiation, such boundaries may help sustain severe storms in environments of low CAPE, provide an environment rich in horizontal and vertical vorticity for storms along the front, and modify storm propagation relative to that expected from the mean cloud-bearing wind (plus storm rotation effects). These boundaries have been associated with tornadic supercells as well as long-lived large hail-producing storms and, unlike some outflow boundaries, may have a lasting role in long-lived severe storms. This study will examine observations of selected warm-frontal severe weather events and examine the impact of these boundaries on severe storms through idealized and real-data numerical modeling experiments.