Welcome to a new season

The setting sun on L'Ile Perrot casts an eerie glow on departing thunderstorms to my east. (ValleyWeather)

September 1 marked the start of meteorological fall, but we still have a few decent summer days left, some years more, some years less. The last holiday weekend of the summer was good in Montreal with a warm and muggy Saturday followed by a near perfect Sunday, sunshine and ideal temperatures of 26C. Labor Day Monday not so good as a series of fronts brought us several rounds of thunderstorms with the late afternoon storms being the most active. A well defined line of storms paraded east across Ontario and New York State into Vermont and southern Quebec around the supper hour. There was lots of lightning with the cells but not much severe weather. The one exception was very heavy rainfall. About 12mm fell in just a few minutes here on L'Ile Perrot while the airport recorded 20mm. Much more fell across the Townships with over 60mm (2 inches) at Sherbrooke. Flooding was reported in the Magog area.

The morning storms skirted us here on L'Ile Perot but did manage to topple some trees on the Island of Montreal as well as produce flooding in Laval. Those storms were along a warm front that was followed by partial sunshine and muggy weather setting up the evening thunderstorms.

Morning thunderstorms toppled this tree in NDG. (The Gazette)

Another front will cross the region today with showers and much cooler weather. Temperatures will struggle to make it to 20C. A cold front late Wednesday will bring in some of the coolest air so far this season with temperatures in the single digits for lows and highs of around 16C by
Thursday.