Overnight thunderstorms rattle the Montreal region

The first thunderstorms of the season rumbled across southern Quebec overnight, waking up many in the Montreal region. More isolated storms are possible tonight and Friday, especially south of Montreal. 

Heavy rain warning for Montreal

As written Wednesday afternoon on this very blog, we had some bone-rattling thunderstorms overnight. One particular lightning strike at 3:25am seemed to wake up the entire West Island as well as off-island communities. Social media lit up immediately with theories as to what the loud sound was. It certainly rattled the windows on Ile Perrot, shook the entire house and set off car alarms, but it was not an earthquake or aliens. It was simply a rare March nocturnal thunderstorm.

A warm front lifting across southern Quebec was the culprit. The cold dense air at the surface was being overridden by very warm air higher in the atmosphere. The thunderstorms were not that intense in nature, with very little wind and only 5mm of rainfall on Ile Perrot. What the storms did have was some pretty intense lightning and thunder. The thunder was capped by the warm air aloft and reverberated back to the surface making the rumble seem much louder and longer than usual. With the cold air at the surface and warm air above it, the warm air will act like a ceiling, or insulator to things like sound waves. The sound from the thunder will hit the bottom of the warm layer and bounce back to the ground. This was not your typical warm, humid summer afternoon storm. So if anybody asks you what that was, you definitely have the answer.

We will have a very warm and windy day in Montreal, with winds increasing to 50km/h out of the southwest. We can expect a record high of 21C (70F). A strong spring storm arrives on Friday, with heavy rain and gusty winds. Rainfall warnings are in effect for Montreal and southern Quebec, with up to 40mm possible. North of Montreal freezing rain and even wet snow is forecast. Temperatures will cool off considerably from Thursday, with highs struggling to reach 10C (50F) in Montreal, and dropping to the freezing point into Saturday. The weekend will be even colder, with flurries possible.

You have to love March in Montreal, never boring.