The federal weather agency is predicting periods of low visibility during heavy flurries.

The severe thunderstorm watch that was in place for Barrie, Collingwood and Hillsdale, Ont., has ended.

The federal weather agency says a period of hot weather will begin Tuesday, with daytime high temperatures reaching in excess of 30 C.

The main threats are wind gusts of 100 kilometres per hour that may cause local power outages and torrential downpours.

Near freezing temperatures are expected during the night for much of the week as a cold air mass settles into the area, according to the federal weather agency.

Under the snow squall bands, visibility will be significantly reduced due to heavy and blowing snow that will quickly accumulate, the federal weather agency says.

Total snowfall amounts of 15 to 25 centimetres are expected.

A frontal snow squall will cross the regions Tuesday night, and lake effect snow bands will continue in a few areas into Wednesday morning.

A snow squall warning has been issued for Midland, Coldwater and Orr Lake, while a snow squall watch is in effect for Barrie, Orillia, Collingwood, Hillsdale, Washago and Lagoon City, Environment Canada says.

Environment Canada says snow squalls are forecast to develop off Lake Huron and Georgian Bay Tuesday morning into the night.