Weather information from the National Weather Service:
What are lake shadows?
(August 6, 2016) – A bit of weather fun for a quiet evening on the Great Lakes: Cumulus clouds often form in the afternoon due to instability generated by daytime heating. A lake shadow is where cooler, stable air off the lake moves inland-preventing cloud development. Did you see the lake shadow today? Check out the latest visible satellite imagery here: https://www.goes.noaa.gov/browse2.html.