Environment Canada warns there could be flash flooding, flooding in low-lying areas, and water pooling on roads on Tuesday as some storm weather moves through the region.
It's issued a rainfall warning and a severe thunderstorm watch.
Some areas could see up to 75 mm of rain before it tapers off later Tuesday evening.
"Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles," read the agency's severe thunderstorm watch. "Hail is also possible. Intense lightning is likely with any thunderstorm that develops. Remember, severe thunderstorms can produce tornadoes."
The forecast calls for showers to end later Tuesday evening before the sky clears up overnight.