Mount Forest, Arthur and Northern Wellington Counties are the areas included in the warning issued on Tuesday. Strong storms are expected to develop Wednesday afternoon and continue into the evening. The weather service said damaging wind gusts will be the main threat, although large hail and a few tornadoes are possible. The special weather statement came one day after Environment Canada issued a heat advisory for parts of Ontario, including Waterloo Region, Guelph and Wellington County. Temperatures in the region soared to 33 degrees Celsius on Tuesday, with humidity reaching 49%. On Wednesday morning, Environment Canada reissued the heat warning for the region. A high of 31C, with humidex values in the upper thirties, is expected throughout the day. An overnight low of 20 degrees Celsius will be followed by slightly cooler temperatures on Thursday, officials said. Thunderstorms are expected to develop over eastern Michigan or Lake Huron Wednesday afternoon and then track east into the evening, Environment Canada said. The threat of severe weather should diminish as storms move east Wednesday afternoon.
