snippet from Milw
Initially, dry Arctic air lingering at the surface will prevent
snowfall from reaching the ground. However, by mid-morning
Wednesday, expect boundary layer to saturate and steady snowfall
to begin. Rates in the initial band will likely be in the
0.25-0.50 inch per hour range as it will primarily be driven by
WAA in the 700-500 mb layer. That being said, high ratio
snowfall is possible as the WAA actually nudges more of the
column into the dendritic growth zone. The highest rates develop
during the afternoon as low pressure begins to lift northward,
WAA in the mid-levels is enhanced, and convergence off Lake
Michigan begins to shift inland with a higher fetch. Rates up to
1 inch per hour are possible during this time frame, especially
in the Milwaukee to Kenosha corridor