Tuesday, July 21, 2015

More thunderstorms today - then cooler & less humid

It was hot at the New Hampshire Motor Speedway for the NASCAR race on Sunday. Thankfully the heavy thunderstorms shown above remained just north of the venue until after the race ended. (Valley Weather Photo)
Another round of showers and thunderstorms is likely today for Montreal along a cold front slipping into Quebec and Ontario. The storms may have some brief heavy rain but should not be as strong as the severe weather outbreak that occured over the weekend. High temperatures will be warm again today near 28C (83F) before a cooling trend to end the week.

Over the weekend strong thunderstorms developed in the very humid air mass locked in place over the region. Tropical dew points and a strong jet stream allowed some of the storms to be quite strong including several funnel clouds and hail. A tornado warning was even issued from Kemptville, Ontario east towards the Quebec border. The Sunday morning storms brought very heavy rain to southern Quebec including 65mm measured at my home on L'Ile Perrot, half of that in a 20 minute period around 6:20AM. Sainte-Anne-de-Bellevue recorded 58mm, while Trudeau Airport had 35mm.

Major flooding from thunderstorms occurred in Barre, Vermont late Sunday night. The photo above is the clean up Monday morning. (VPR Photo)
The other story over the weekend was the elevated heat and humidity levels making it very uncomfortable. Montreal had a temperature close to 30C (86F) on Sunday with humidex readings near 40C (104F). I was at the NASCAR race in Loudon, New Hampshire where the temperature soared to 32C (90F) with heat index values well over 100F. Several of the drivers had to be treated for heat related issues, and the venue actually ran out of bottled water! Elsewhere the thunderstorms produced major flooding across portions of northern Vermont and New Hampshire. In Barre, Vermont mud and water flowed into several neighborhoods after torrential rain from severe storms. Nearly 80 homes were flooded and some have been left uninhabitable.

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