. . . A LAKE ENHANCED SNOW EVENT
. . . The majority of the heavy snowfall during the southeasterly segment may be characterized as a "lake enhanced", or more properly, a "combination" lake effect snow event (Dockus, 1985). Typically in such events, marginal or even conditional instability in the overwater environment and low capping inversions limit the development and/or intensity of significant lake effect snows. However, by superimposing a larger scale lifting mechanism (such as a mid-tropospheric shortwave trough) on the convective boundary layer, capping inversions can be lifted or erased, and parcels are lifted to saturation earlier in their overwater trajectories. In an unstable or conditionally unstable overwater environment, this often leads to bursts of relatively deep and intense lake effect convection embedded within weaker and broader synoptically forced precipitation. In this particular case, delta-T values between the water surface and 850-mb were at least 13C over Lake Huron, meeting accepted criteria for lake effect snow development (Rothrock, 1969). Clearly, large-scale lift associated with the approach of the short-wave trough enhanced the lake effect convection embedded within the larger-scale precipitation field and organized the low level flow into a persistent and confluent southeasterly pattern pointed toward eastern Upper Michigan.
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