Tuesday's severe storms in Ontario could have produced a gustnado
Wednesday, May 14, 2014, 8:06 AM - For the second day in a row, conditions were favourable for severe storms across southern Ontario Tuesday.
The first tornado watch of the season was issued for the Windsor area on Monday, followed by the first tornado warning for southern Grey County on Tuesday night.
CANADA'S TORNADO ALLEY: Tornadoes in Canada: Everything you need to know
A warm, humid and unstable air mass was in place and as a pre-cold frontal trough swung through the area, storms started to develop.
"As those storms moved in over land across southern Ontario, they came into contact with the lake breeze boundaries that were in place," says Weather Network meteorologist Dayna Vettese. "As the storms interacted with those boundaries, the storms were able to spin briefly."
This video from storm spotter Dave Patrick shows a lot of turbulent motion within the storm.
"We can see dust swirling at the bottom along the ground as well as turbulent and rotation motion in the clouds above," explains Vettese. "Environment Canada will need to investigate to determine whether this was a full-fledged tornado (not likely), a landspout or gustnado (more likely). You will also note that there is no condensation funnel. That means even though the rotation on the ground connects to the cloud above, you can’t actually see the cloud in between because it hasn't condensed."
WHAT IS A GUSTNADO?
"A gustnado is an expression for a short-lived, shallow, and generally weak rotating column of air," Vettese says. "Gustnadoes are usually visualized by a rotating dust or debris cloud. Gustnadoes generally form on the leading edge of a gust front or shelf cloud. Tornadoes, though in the same family as gustnadoes, form under mesocycles in a supercell thunderstorm."
Vettese adds that gustnadoes can form when there is an advancing gust front with turbulent motion.
Gust front almost on the Lake Huron shores. Impressive pic.twitter.com/0xNkI9Ce7G— Mark Robinson (@StormhunterTWN) May 13, 2014
"Gustnadoes are generally weak and don’t do much damage, however, residents are still urged to take precaution when they form.
"They can loft debris in the air such as branches and tumble weed, which can impact you or vehicles," Vettese says.
Despite the severe storm threat for the past couple of days, Vettese says it's a "typical" start to the severe weather season.
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"It’s not rare to see these types of events happen throughout May as we move into summer severe weather season," says Vettese.
Does that mean the severe storm threat will be high this summer?
"We can't really gauge how the summer will turn out from a severe weather standpoint because convection (thunderstorms) are a small scale phenomenon compared to large low pressure systems. These forecasts are not mostly days in advance rather than months," Vettese adds.