A multi-day threat for thunderstorms will continue on Wednesday in southern Ontario. The active, recent stretch of thunderstorm activity could continue on Wednesday, with a severe chance across a good swath of the lower Great Lakes region in southern Ontario. Risk of severe storms on Wednesday in southern Ontario, but there's a catchA potent setup is expected to come to fruition for southern Ontario on Wednesday. Upper-level smoke forecast Ontario Wednesday afternoonIn eastern Ontario, there will be an additional risk of severe storms across the provincial border with Quebec. Eastern Ontario precipitation timing Wednesday eveningBy Friday, a provincewide cooldown is expected to bring temperatures down to slightly below seasonal values.