Heat warning remains in effect for Montreal

A spectacular photo of the intense lightning taken by Quebec Vortex last night on the South Shore in La Prairie.
More on Quebec Vortex at this link. 

Our longest and hottest heatwave of the summer is moving into its 5th day in Montreal with temperatures expected to reach 32C (90F) today. If it does, it will set a record high for the date, the previous being 31.7C (89F) in 1960. Yesterday Trudeau Airport had a poorly timed shower around 4pm, enough to drop the temperature down a degree or two, preventing us from a record high by a few tenths of a degree. The official high was 31C (88F) but most other reporting stations around the island including here on L'Ile Perrot, reached 33C (91F).

The airport is typically cooler as the breeze off Lac St. Louis can knock the temperature down a couple of degrees. It remained very warm and muggy overnight with lows in the middle 20's. Last evening a spectacular thunderstorm with lots of vivid lightning moved from the South Shore across the downtown area around 10pm. The storm dumped only 2mm of rain here on L'Ile Perrot but 5mm at the airport in Dorval and 20mm downtown at the McTavish station.

High pressure off the US east coast will continue to pump warm and humid air north into southern Quebec today. The heat advisory remains in effect as humidex values are forecast to exceed 40C (104F) this afternoon. As with Tuesday, there remains a risk of thunderstorms this afternoon and evening. Tonight will be muggy again with warm overnight lows of 24C (76F) in the city. On Thursday a cold front will approach eastern Ontario and western Quebec with showers and thunderstorms by late in the day. It will be warm again with a forecast high of 30C (86F). Cooler air with lower humidity arrives by the weekend.