Hot and stormy July continues

More strong thunderstorms are expected Monday afternoon across extreme eastern Ontario and southern Quebec.

Strong thunderstorms are possible in eastern Ontario and southwest Quebec today from 12 noon through 8pm. A severe thunderstorm watch may be needed later this morning.

Temperatures are on the upswing today following a dry and cooler weekend. A warm front has already lifted north across the St. Lawrence Valley this morning with scattered showers. The humidity will build in quickly, with high temperatures near 28C (83F). The humidex reading will rise into the upper 30's. The air mass will quickly become unstable, with strong thunderstorms likely in Montreal by mid to late afternoon. Some of the storms could produce very strong winds, small hail and heavy downpours. The storms will develop by late morning in Ontario, ahead of a trough and cold front, before moving into Quebec and New York State.

A strong gust front and thunderstorm approach L'Ile Perrot around 6pm Friday night. The storm produced winds in excess of 90km/h, knocking down trees and power lines in several west end suburbs. (Valley Weather Photo)

The setup is very similar to Friday when L'Ile Perrot and the southern portion of Montreal island were hit by a rather strong storm around 6pm. Sweeping from west to east, the storm produced winds up to 90km/h. Numerous tress were brought down, especially along south facing shorelines. Power outages were widespread, adding to the workload of Hydro Quebec, still trying to restore power from Thursdays thunderstorms.

Today's front front clears the region overnight Monday, with a partly cloudy, less humid, and cool day Tuesday. The high temperature will be near 22C (72F). After the one day break, the heat will begin building again Wednesday, reaching into the low 30's (up to 90F) by next weekend. We can also expect an increase once again in the humidity and the likelihood of more thunderstorms.