Special Marine Warnings can describe sudden hazardous winds, hail, lightning and rapidly building waves. On western Lake Erie, safe-harbor decisions need to happen before the storm reaches the route.
Identify more than one reachable harbor, keep the VHF monitoring channel available, and know how long the boat needs to get inside protected water. A phone radar image alone is not a complete warning system.
If thunder is heard or a warning covers the route, seek appropriate shelter early. Do not wait for visual confirmation of the strongest part of a storm.