Severe thunderstorms possible

A sign of the seasons - last nights full Harvest Moon as seen in southern California.

It is still hard for me to believe that summer is nearing an end, especially with the way the weather has been for the last 48 hours. There is however, evidence on the weather map this morning that changes are coming. Lets start with yesterday's muggy high of 26C in Montreal, well above normal for this time of year. Other cities in the region were equally warm with Ottawa and Toronto at 29C. We can expect much the same today with a mix of sun and clouds, warm and windy with an increasing likelihood of thunderstorms at any time today. Last evening strong storms moved along the Ottawa River and into the central and north end of Montreal, downtown and Laval. About 7mm of rain fell at the airport but much more locally in the city. It remained dry across my area with no rain or thunder.

This morning we are already under a Severe Thunderstorm Watch here in southwest Quebec as storms develop along the St. Lawrence Valley and drift northeast. The watch in posted until 9:30am. Look for more watches and warnings this afternoon as a potent cold front sweeps across the area from Ontario. The main threat will be heavy rain, perhaps 30mm, but small hail and strong winds are possible as well. The front will usher in much colder air, just how cold? Well frost and freeze warnings are in effect across the Dakotas and Minnesota with below freezing temperatures forecast tonight. More frost is likely across northern Ontario and Manitoba by the weekend. So I imagine we will see single digits for lows in southern Quebec and teens for highs as fall begins to influence our weather.