Warm and humid weather week ahead for southern Quebec

Stationary thunderstorms over northwestern Clinton County, New York, along the Quebec border, produced flash flooding on Saturday night into Sunday. Up to 200mm of rain is estimated to have fallen in just a few hours. Above, the Great Chazy River flooded the Blue Haven Campground in Ellenburg Depot, NY, forcing evacuations. (Photo courtesy Tammy Arbour)

The coming week will be very warm and humid in Montreal.

Another round of scattered showers and thunderstorms is possible on Monday and Tuesday, with southern Quebec remaining entrenched in a warm, humid and unstable airmass. Temperatures will be warm to even hot all week, with highs ranging from the upper 20s into the low 30s across the region. Factoring in the humidity, and conditions will feel oppressive at times in the middle to upper 30s. Little relief is expected during the overnight hours, with lows around 20C (68F). 

A flooded home along US Route 11 near Ellenburg, New York on Sunday, July 2.  Ellenburg is 100 kilometres southwest of Montreal. (WCAX)

Over the weekend, strong thunderstorms developed along a warm front Saturday morning, with thousands of lightning strike observed as the storms moved across the Island of Montreal and Laval. A lightning strike in Laval-sur-le-Lac ignited a fire damaging a two storey residence. Heavy rainfall and hail up to 3cm was also reported. The rain was much needed here on Île Perrot, where 34mm fell Saturday (I recorded only 49mm for the entire month of June). At Trudeau Airport, 30.8mm was reported, with 55mm in both Riguad and St. Anicet.

Further south, nearly stationary "back building" thunderstorms dumped between 100-200mm (4-8 inches) of rain across northeastern New York State, specifically Clinton and Franklin Counties. There are radar estimates of even more locally. The torrential rain, falling in just a few hours Saturday night, produced severe flash flooding along the Great Chazy River. A friend was staying at the Blue Haven Campground in Ellenburg, New York, where evacuations were ordered in the wee of hours of Sunday morning. Numerous swift water rescues were carried out. Several homes and businesses are flooded as well, with numerous roads closed and washouts reported. More storms are forecast for the same area Monday.

Extensive flooding from thunderstorms at Blue Haven Campground in Ellenburg Depot, New York. (Tammy Arbour)

Back in Quebec, flash flooding was reported in the Saguenay region after 130mm of rain fell Saturday. In Rivière-Éternité, a state of emergency has been declared after flash flooding in that community forced more than 200 residents to be evacuated. The SQ and firefighters are searching for at  least two individuals missing after their cars were swept away in the flood waters.