[B767Driver]

If those were SAT readings, my guess is that some warm air off the lake was affecting local temps below 10,000 in the MKE area. It does seem to occasionally create a local inversion from time to time.

From my inflight experience, it does not take much altitude for precip types to change forms. Mainly just temperature. Right at the freezing level, inflight anyway...it can be a mixture type of precip that gets pretty messy.