Yeah but the end of the sentence mentions the SGZ, so I think they mean the entire lower atmosphere as a whole, which i agree with. The boundary layer per say supports some lake enhanced precipitation. If you had a legit lake enhanced setup you would be upping ratios considerably over 10:1 because you would be getting dendrites from the convection mixing in with the crappier flakes from the synoptic storm.
They mention the lake enhancement at the end of the storm, which would do exactly as you said its probably going to.