The Structure and Motion of Severe Hailstorms. Part II: Multi-Cell Storms

Abstract

Two case studies are presented of multi-cell storms in Alberta which displayed separate modes of propagation. Discrete propagation occurred on the right flank of both storms as in multi-cell storms previously documented by Browning and Ludlam in England and Chisholm in Alberta. The storms which were synthesized by Browning and Ludlam and by Chisholm deviated to the right due only to discrete propagation. The individual cells of the first storm (Alhambra storm) propagated continuously to the right in addition to the discrete propagation, which caused the Alhambra storm to deviate ?55° to the right of the mean environmental winds. On the other hand, the individual cells in the second storm (Rimbey storm) were observed to propagate continuously to the left of the mean environmental winds. The continuous propagation of the cells to the left was offset by the discrete propagation to the right. Schematic models of the Wokingham, Alhambra and Rimbey storms are presented.