The thunderstorm forecast is issued daily from April 1 to September 30.
Monday, June 21st:
Severe thunderstorms are forecasted for parts of southwestern Ontario this morning, due to an area low-pressure, and large amounts of storm energy. As well as this, there will be a decent amount of helicity (the rotation in the updraft of a storm) in this region, which will add an increased tornado risk. Large hail measuring between 2-5 cm in width, heavy downpours, and wind gusts up to 110 km/h are all likely as well.
Isolated-severe thunderstorms are possible in numerous areas of Ontario, and Quebec today. With an unstable atmosphere due to a low-pressure system, these storms will be in an area with enough instability to create supercells, and potentially even an isolated Tornado. Large hail measuring up to 2-3 cm, isolated heavy downpours, and wind gusts up to 100 km/h are all likely with these thunderstorms.
Non-severe thunderstorms are forecasted for numerous areas of Canada on Monday. Small hail, wind gusts up to 90 km/h, and isolated flooding may occur with these storms.