After days of sunshine, parts of southern Ontario are under a severe thunderstorm watch as a fast-moving storm rolls across the Great Lakes.

Environment Canada has issued a severe thunderstorm watch for:

  • Hamilton
  • Dunnville-Caledonia-Haldimand
  • Elgin
  • London-Middlesex
  • Niagara
  • Oxford-Brant
  • Sarnia-Lambton
  • Simcoe-Delhi-Norfolk
  • Windsor-Essex-Chatham-Ken

Severe thunderstorms may be capable of producing torrential downpours with up to 50 mm of rainfall, Environment Canada warns. Lightning is expected to follow the storm clouds, and wind gusts of 90 km/h are possible.

In a statement Monday morning, Environment Canada said that severe thunderstorms can produce tornadoes, and warned residents of the affected areas to stay indoors.

Soaked start to the week

In Toronto, commuters can expect delays as roads will be slick with rain. Showers are expected to end Monday morning, but there is a 60 per cent chance of more rain for the rest of the day. There is a risk of thunderstorms, but no watches or warnings are in effect.