Monday, June 26, 2017

Unsettled weather week ahead for Montreal

Torrential rain and thunderstorms over midwest Ontario on Friday, June 23, produced widespread flash flooding.
(CTV News London)
I hate to be the bearer of bad news for those, like myself, wanting a hot and dry summer, but it is not looking that way for the foreseeable future. This past holiday weekend, while not being a total washout here in Montreal, can best be described as unsettled. If you did not like the weather where you were, you just waited a few minutes and it changed. This made the forecast difficult at best, and the same holds true for the balance of this week. Most of this past weekend was dry here in Montreal, and temperatures were fairly warm. The heavy rain expected from the remains of tropical storm Cindy remained to our south and over Ontario.

Thunderstorms developed rapidly on Saturday, June 24 across eastern Ontario, including Cornwall, shown above. The storms, for the most part, missed the Island of Montreal. (ValleyWeather Photo)
Copious amounts of rain fell over midwestern Ontario Friday, resulting in flash flooding. Over 150mm fell in Mount Forest, with widespread flooding reported. A state of emergency was declared in the Township of Mapletown and Harriston. Closer to home, strong thunderstorms rattled around southern Quebec all weekend long. Hail and gusty winds were reported in the Ottawa Valley and across the Laurentians. Strong storms also passed to the south of Montreal, along the US border. However here in the city, only a few millimetres of rain fell, with very little by way of thunder.

An unseasonably cool air mass over the central Great Lakes will generate a series of weak disturbances this week. They will move across our region rather quickly, each producing clouds and instability. There will be an almost-daily chance of showers and scattered thunderstorms, with temperatures remaining cool for this time of year, either side of 21C (70F) through Thursday. As a result of the cool pool of air aloft, there is also the chance of small hail with any thunderstorms that develop. Overnight lows will be chilly under generally clear skies, around 12C (54F).

Briefly looking ahead to the Canada Day weekend, we can expect another round of warm and humid weather, with the risk of thunderstorms and possibly heavy rain. However, keep in mind, this is similar to what we were expecting this past weekend, and the weather turned out mostly dry in Montreal.

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