News

Chris Scott

Forecast Operations Manager
The Weather Network

"Funnel Clouds"
April Tetreault - Tilbury, ON June 23

Why the wild weather?

Lightning, hail, funnel clouds and tornadoes... a typical June in Ontario and Quebec? Like most things in weather, the answer isn’t yes or no, but lies somewhere in between. Thunderstorms and severe weather are expected this time of the year, but you’d be right in thinking that most of us have seen more than our fair share. However, it’s not simply the number of thunderstorm days that has been unusual. Many days, such as Father’s Day, have featured multiple rounds of storms, with some places seeing up to 5 separate storms in the same day! Colder than usual air 3 to 5 km above the ground has meant free ice for summer drinks and trouble for cars and gardens with hail hitting areas from Wasaga Beach to Hamilton. A hail storm made north Toronto look more like Edmonton or Calgary with drifts of hail. Funnel clouds have been common, with the tornado hot spot in areas north of London including Lucan and Bryanston. Montreal and the South Shore were hit earlier in the month with a storm than overturned trucks on the Champlain Bridge. So what’s going on?

The explanation

Meteorologists always blame everything on the jet stream... it deflects criticism from us after all, so let’s do that again. Yes, the jet stream is to blame. Think of the jet stream as a highway that weather systems follow around the globe, from Japan to Canada to England to Russia and back again. The tricky thing is this highway, along with its curves and bends, is constantly moving (predicting the change in the jet stream flow is what large-scale weather forecasting is all about). This constant ebb and flow of the jet stream, or storm track, gives us our variation in weather patterns over the course of a few days. June features the perfect recipe for thunderstorms: maximum solar energy, humid buoyant air, and a jet stream that carries trouble-making disturbances along its track. The added kick this June has been just the right combination of humid buoyant air where we live, coupled with cooler air a few kilometers up - bringing a jet stream disturbance into the scene is like releasing a cork that is being held under water - thunderstorms result when this warm buoyant air explodes upward. You can literally watch these clouds grow as the air (updraft) rises vertically at highway speeds up to a height greater than 10 km. We’ve seen more days than usual this June with that perfect setup of thunderstorm ingredients.

The forecast

Once again, a strong jet stream triggers more severe weather this weekend in advance of a cold front. Check your local forecast for details, but don’t forget to watch The Weather Network on TV to get the big picture and explanation - predicting individual storms is like trying to figure out which popcorn kernel on an evenly heated tray will pop first. It’s an impossible task, but generally we have a good idea of the regions where storms are likely. After storms have formed, radar, lightning data, and your eyes and ears are the best tools to help you steer clear of severe weather.