While warnings about heavy rain for the London area have ended, the region is bracing for more heat as Toronto starts to dry out.

Environment Canada had  issued a Special Weather Statement for London-Middlesex, Elgin, Oxford-Brant, Norfolk, Chatham-Kent and Windsor-Essex.

Showers and thunderstorms were expected to bring heavy rain into early Wednesday afternoon, with local rainfall accumulations of 20 to 40 mm.

A heat warning is also in place for Chatham-Kent and Windsor-Essex, where temperatures hit 35-40C with the humidex on Wednesday.

And it's expected to get worse on Thursday, with temperatures in the low 30s, then even more challenging on Friday and Saturday.

By the end of the week, Environment Canada says temperatures could easily reach the mid-thirties with humidex values in the mid-forties.

If the mercury climbs as forecast, the temperatures could represent the highest temperatures so far this year for the area.

Rain swamps Toronto roads

Meanwhile drivers in the Toronto area were being warned to be cautious after the heavy rain led to flash flooding.

Some ramps to Highway 401 were underwater on Wednesday morning, and drivers in some areas were abandoning vehicles or had to be rescued after being unable to continue.

OPP Sgt. Kerry Schmidt warns drivers to aware it's hard to tell if there are potholes or barriers under the water.

With files from The Canadian Press