Conditions are favorable for thunderstorms in many US states over the next few days. A large northeasterly swell will form in the jet stream over the Great Plains next week and start a chain reaction, said Joe Lundberg, senior meteorologist and long-range forecaster at AquaWeather.
Disturbances moving along the jet stream at the boundary between cold air and warm air can trigger thunderstorm complexes that can last for days and travel hundreds of miles. The same could happen to our neighbors to the south.
The border area between North and South Dakota and Minnesota may be affected by a mesoscale convective system, with expected manifestations beginning around 6 PM Sunday. According to meteorologists, the system, which will mainly affect the northern prairies and the central and southern Appalachians, has all the characteristics of a terrico, according to current forecasts.
A rare and devastating event
According to NOAA, certain criteria are used to qualify as a derecho:
- If structure-related wind damage extends beyond 650 kilometers;
- If the disturbance is at least 100 kilometers wide;
- If the wind speed is 93 km per hour over most of it.
As meteorologist Nicolas Lessard explained, linear winds and an intense front in one direction are on the system’s menu, which “will topple trees and tear roofs off”.
Also note that a tereco feeds itself: it allows it to travel very long distances without suffocating. In addition, it requires a large amount of moisture, thus creating favorable conditions for its deployment.
“Unlike hurricanes, there are no circulations in this system, but rather a frontal mechanism. However, some individual cells can form, hence the danger of hurricanes. »
A reminder of a stormy May
Terreco is currently moving over the US Midwest due to a weather event observed in Ontario and Quebec during the third week of May 2022. However, in an extremely rare event north of US borders, this powerful storm hit. A good part of the United States, Ontario and Quebec, where the eight victims (including two deaths in Quebec) share many of the characteristics that are emerging in North America these days.