Effect of vertical wind shear on numerically simulated multicell storm structure

Abstract

We found small shear values produced slowly moving storms which generally exhibited simple oscillations with time, fitting the classic multicell model. Larger shears resulted in complex oscillations similar to what has been termed "weak evolution', culminating in a nearly unicellular storm in the most extreme case. The transition between the strongly and weakly evolving modes was abrupt in the wind shear spectrum, and the temporal behavior of the precipitation production was quite different between the two regimes. An important result is that none of the model storms suffered a terminal decaying phase, certainly not within a reasonable period of time. This suggests that the storm itself does not sow the seeds of its own demise, at least for the favorable, homogeneous environment conditions considered and the simple, strictly two-dimensional framework adopted for this study. -from Authors