In this image you can clearly see the connection that the Lake Ontario band has back across southern portion of the province of Ontario, then across northern lake Huron, and finally all the way back to the southern end of Lake Superior.  The rest of the cellular cloud cover across the great lakes is a result of the diurnal warming that occurs under a mid-march sun, producing lots of cumulus-type clouds.  That diurnal activity has resulted in a rapid disorganization of the weaker  snowband off Lake Erie, which was just too weak to overcome the competition for moisture produced by widespread diurnal cloud development.