We are watching the risk for severe thunderstorms across Southwestern Ontario this evening. Thunderstorms are expected to develop across Michigan and move east before slowly weakening upon entering Ontario.
Areas in yellow and marked with a '3' can expect a moderate risk for severe thunderstorms. This includes Essex County and Chatham-Kent. Across Chatham-Kent, severe thunderstorms are possible as they weaken from Essex County. The main threat is lingering storms producing hail near 2cm and some briefly gusty winds towards 90km/h. Lightning will be present as well.
Across Essex County, severe thunderstorms are possible after crossing from Michigan. Severe thunderstorms producing large hail up to 2-2.5cm may be possible, closest towards Michigan, before weakening as they move into Ontario and Essex County. Heavy rain is expected. Frequent lightning is expected. Gusty winds up to 90km/h are possible.
There is an isolated, non-zero tornado threat across the moderate region, with the best risk along the Lake Erie shores from Pelee to Amherstburg, extending across the Detroit River to Windsor.
Areas in green and marked with a '2' can expect a low risk for severe thunderstorms. This extends from Goderich through to Stratford and Brantford extending to Dunnville, and everything south to Lake Erie. Strong to isolated severe storms will develop and move across this region. Heavy rain and gusty winds between 70 and 90km/h are possible. Hail is one of the main concerns as hail between 0.5 and 1.5cm is possible, with the best risk towards the south near Lambton County extending towards Elgin Count. The threat for severe thunderstorms in this region is very low, expect mainly strong thunderstorms, although non-'severe'.
Elsewhere, areas to the north extending from Owen Sound through to Toronto, including everything south, have a low risk of seeing thunderstorms, non-severe in nature. The best risk to see thunderstorms will extend from Lake Huron near Amberley through to Kitchener, Hamilton and the Niagara region.
It is questionable if severe storms will survive far into Ontario after reaching the Detroit River and St. Clair River. Either way, we will be watching and posting about any severe threats which do develop.