Residents near the Alberta-Saskatchewan border are being urged to keep an eye on the skies this week, as conditions continue to build for severe thunderstorms capable of producing large hail, damaging wind gusts, and even a tornado or two.
A cold front and warm-sector trough are pushing southward through the Prairie provinces, drawing moisture into southern Saskatchewan and Manitoba. The result? A recipe for strong storms, particularly in areas from Medicine Hat east through Maple Creek, Hannah, and Oyen.
Forecasters expect thunderstorms to develop late in the afternoon.
We’re seeing a mix of ingredients that support rotating thunderstorms, or supercells. These are the types of storms that can produce hail the size of loonies or larger, and occasionally a tornado.
A layer of warm air higher in the atmosphere, known as a "cap," should hold storms back until late afternoon, but once it breaks, storm development could be fast and fierce.
Wind shear, a key ingredient in severe weather, is also present. In simple terms, that’s when winds change speed and direction with height, helping storms to spin. Combined with high moisture levels and atmospheric instability, it raises the risk of organized storms.
The highest risk areas include southwest Saskatchewan, including communities like Leader and Maple Creek, as well as southeast and Central Alberta. While large hail will be the main concern, meteorologists note the presence of a "dry line" could trigger a tornado, particularly as storms fire along the foothills and move eastward.
Further north, areas around Lloydminster and northeast of Edmonton may see isolated funnel clouds or even brief landspout tornadoes, especially along a surface trough and deformation zone stretching into the Peace Country.
Forecasters say while the storms could be intense, they should be relatively fast-moving, limiting widespread flooding. Still, pockets of heavy rain are possible.
Scattered showers and thunderstorms may persist into the overnight hours in Saskatchewan, with a slight risk of isolated severe cells continuing into early Wednesday morning.
Environment Canada advises residents to monitor weather alerts and have a plan in place in case severe weather approaches. Storm watches and warnings may be issued throughout the day.