Turns out there was what is known as a mesoscale vortex over the lake this morning. You can see it in the loop below. Note how it drifts southward across the SW corner of the lake.
How about a high res MODIS image? At this time, the center of the hook, which almost forms an eye, was sitting over the far SW corner of the lake.
This lake-effect stuff is sure complicated. I'm not sure if this vortex was lake induced or something in the larger-scale flow that just happened to be passing over the lake.