Jet stream patterns play a decisive role in shaping the weather on the Canadian Prairies, especially when it comes to prolonged wet periods. Here’s how:
1. Jet Stream as a Weather Conveyor Belt
- The jet stream is a fast-moving ribbon of air high in the atmosphere that acts like a conveyor belt, steering weather systems such as areas of low pressure, storms, and rain across vast regions.[1][2]
- When the jet stream is positioned over the Prairies, it can guide repeated storm systems into the region, resulting in ongoing rounds of precipitation.[2][1]
2. Waviness, Blocking, and Persistent Patterns
- The jet stream often develops large meanders called Rossby waves, which can slow down or stall its movement. When this happens, weather systems (like rainstorms or low-pressure areas) can linger over a region much longer than usual.[1][2]
- These stalled or "blocking" patterns are a main driver behind weeks-long wet spells, as they prevent new air masses from moving in, allowing rain and thunderstorms to repeatedly impact the same areas.[3][2]
3. Intensification of Storms and Rainfall
- When the jet stream flows over an area of low pressure, it acts to intensify these systems by drawing air out of the top, which deepens the low and can result in stronger storms with heavier rainfall.[2][1]
- The interaction between the jet stream and atmospheric moisture contributes to the development of organized thunderstorm clusters and widespread rain.
4. Climate Change and Jet Stream Dynamics
- Arctic amplification and climate change are causing the jet stream to become weaker, slower, and more prone to meandering. This leads to a higher frequency of blocking events and persistent weather extremes—prolonged wet, dry, hot, or cold spells.[4][5][1]
- Weaker jet streams are less effective at pushing systems eastward, which means rain-bearing weather can sit over the Prairies for days or weeks.[5][2]
5. Regional Impacts
- The exact impact depends on the shape and position of the jet stream. A southward dip (trough) tends to bring cooler, wetter conditions, while a northward bulge (ridge) favors dry, warm weather.[6][1]
- For the Prairies, a stalled trough can repeatedly funnel moist air and storms into the region, causing extended wet periods.
In summary:
Prolonged wet weather in the Canadian Prairies is often a direct result of a slow, meandering, or blocked jet stream pattern. This pattern prevents quick movement of weather systems, allowing storms to repeatedly affect the region and prolonging periods of rain and active thunderstorms. In recent years, climate change has made these patterns more frequent, contributing to wetter extremes and longer-lasting events.[5][1][2]
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- https://www.maximum-inc.com/learning-center/what-is-the-jet-stream-how-it-does-it-impact-our-weather/
- https://www.metoffice.gov.uk/blog/2025/what-is-the-jet-stream-and-how-does-it-affect-our-weather
- https://arctic-council.org/news/shifting-winds-how-a-wavier-polar-jet-stream-causes-extreme-weather-events/
- https://www.cbc.ca/news/science/changing-jet-stream-extreme-weather-linked-humans-1.4043390
- https://www.newscientist.com/article/mg26535264-100-is-a-broken-jet-stream-causing-extreme-weather-that-lasts-longer/
- https://www.cordulus.com/glossary/jet-stream
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