Much of southern Ontario remains under a special weather statement Monday, with warnings of additional rainfall, heavy downpours and continued muggy conditions through the afternoon and evening. CTV News meteorologist Julie Atchison said scattered showers and thunderstorms are expected to continue developing through the late afternoon, with some areas at risk of significant rainfall. “We could see up to 30 millimetres of rain if communities find themselves under one of the heavier thunderstorms,” Atchison said Monday. The unsettled weather is being fuelled by an extremely humid air mass lingering across the region. Temperatures were hovering between 21 C and 26 C Monday afternoon, with warmer conditions reported toward Essex County. Atchison noted that Windsor-Essex is also facing increasing heat concerns, with a heat warning expected to remain a factor in the coming days as temperatures continue to climb. “Heat and humidity are really going to play a role over the next several days,” she said. While forecasters expect a brief lull in storm activity during the evening, the threat of additional showers and thunderstorms is expected to return Tuesday afternoon. Tuesday’s forecast calls for a mix of sun and cloud, along with another chance of showers and thunderstorms as daytime heating combines with the humid air mass. Overnight temperatures are expected to remain unusually warm for late August and early September. London is forecast to drop only to about 21 C overnight, while communities across Midwestern Ontario are expected to see lows ranging from 19 C to 22 C. The heat is forecast to continue through midweek, with daytime highs between 29 C and 31 C over the next several days. Atchison said actual temperatures could vary depending on the amount of cloud cover that develops across the region. “The one constant is that the heat and humidity will stay with us for the next few days,” she said. Looking ahead, conditions are expected to gradually become more seasonable heading into the Labour Day weekend. Thursday is forecast to be mainly cloudy, while Friday will see a mix of sun and cloud. Similar conditions are expected through the holiday weekend, with a mix of sun and cloud forecast for Saturday, Sunday and Labour Day Monday. Daytime highs are expected to settle closer to seasonal norms, ranging between 24 C and 25 C. Although meteorological fall begins Tuesday, Atchison said summer-like warmth is not ready to leave Ontario just yet. “We welcome meteorological fall tomorrow, but the summer air is holding on,” she said.
