UPDATE | Fog advisory ended for St. Catharines, Grimsby & Northern Niagara

Near zero visibility in fog is expected or occurring.

Dense fog will continue this morning for areas close to the shore of Lake Ontario. The fog will gradually improve late this morning.

Visibility may be significantly and suddenly reduced to near zero. If travelling, be prepared for areas of near-zero visibility. If visibility is reduced while driving, turn on your lights and maintain a safe following distance.