This loop of Rapid Scan Operations (RSO) NOAA GOES-8 visible channel imagery shows several interesting features over the Wisconsin and Lake Michigan region on 25 May 2001. A gravity wave train (apparently originating as a low-level convective outflow boundary over northern Lake Michigan) propagates southwestward across the lake, eventually reaching the lakeshore counties in central Wisconsin. The fog and stratiform clouds that existed over Lake Michigan was dissipating in the wake of the gravity wave, but as the wave feature intersected the coastal portions of Manitowoc and Sheboygan counties in Wisconsin (outlined in yellow), fog and stratus was driven inland several miles. The air temperature at Manitowoc (identifier KMTW) dropped into the low to middle 40's F, and remained nearly 10 degrees cooler than surrounding locations due to the fog/stratus and onshore flow.
Inland, over southeastern Wisconsin, new convection can be seen to develop as a result of intersecting low-level convective outflow boundaries near the Wisconsin-Illinois border. Several cold air funnels were reported with this convection across southeastern Wisconsin.