Summer wasted no time arriving in Ontario. Extreme heat scorched a good portion of the province Tuesday, with peak temperatures hitting the low 30s in some areas. This will persist for another day Wednesday before moderating on Thursday. Wednesday also features a storm and flood threat for eastern Ontario and southern Quebec. The potential for severe storms with torrential rainfall exists, potentially bringing local totals of 60-100 mm through Thursday. More on Wednesday's heat and storm threat, and what lies beyond, below.
THIS WEEK: HEAT WARNINGS STICK AROUND FOR ONE MORE DAY, SEVERE STORM, HEAVY RAINFALL POTENTIAL
The province has just experienced the hottest and most humid air so far this year on Tuesday, with temperature records broken at Pearson International Airport and feels-like values that exceeded 40 in many areas.
Wednesday will see much of the same heat moving into eastern ontario and southern Quebec along with a severe thunderstorm risk. The highly humid atmosphere will enhance rainfall totals, posing a risk for localized flooding concerns before conditions cool off Thursday.
A cluster of storms is forecast to develop Wednesday afternoon across parts of eastern Ontario and southern Quebec. With limited instability, most storms are forecast to stay non-severe in nature. However, a few storms may meet severe warning criteria with locally strong wind gusts and torrential rain.
Confidence in storm development across the Greater Toronto Area (GTA) and the Niagara Peninsula is low, but isolated storms are possible late afternoon.
Heading into Thursday, localized flood concerns grow. Forecasters are watching an axis of very heavy rain and slow moving thunderstorms, forecast to develop across far eastern Ontario and southern Quebec.
A stalled system in a high moisture environment shows potential that this narrow band of rain could amount to 30-60 mm, locally up to 100 mm, through Thursday. Flooding is a possibility, and forecasters will be closely watching the Montreal region and surrounding areas.
IT IS HOT IN SOUTHERN ONTARIO, TIPS FOR HEADING OUTSIDE IN THE HEAT
As for what's remaining of the heat, Tuesday and Wednesday overnight won't provide any relief with some areas remaining well above the 20-degree mark as the sun sets. It could be uncomfortable sleeps for many, even with the proper cooling equipment. Cooler air is expected to arrive by Thursday.
Spectacular late summer-like weather for southern Ontario Thursday and Friday with abundant sunshine, low humidity, and comfortable temperatures. Clouds will linger through Thursday for southern Quebec, but will see increasing sunshine Friday.
A stronger cold front will then track across the region Sunday with showers and thunderstorms followed by cooler weather for the start of next week.
Temperatures are expected to be near seasonal, possibly even a few degrees cooler than seasonal for a couple days, during the final few days of June and through the Canada Day long weekend.
WATCH: HOW TO BEAT THE HEAT; TRICKS TO KEEP YOU COOL
Stay tuned to The Weather Network for the latest forecast updates for Ontario.