Severe Thunderstorms Possible in Alberta & Saskatchewan; Damaging Winds, Large Hail, Tornado Threat

We are watching the risk for severe thunderstorms across portions of Alberta and Saskatchewan, including the risk of an isolated tornado or two.

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Alberta:

Thunderstorm Forecast, for Southern Alberta. Issued June 27th, 2019.

In Southern Alberta, we are watching the risk for isolated thunderstorms to develop along the Alberta Foothills and into the Far South, near Lethbridge and Carway. These thunderstorms are expected to move east into a more favorable environment for severe thunderstorms.

We have highlighted a 'strong' risk for severe thunderstorms in orange or marked with a '4'. This includes a large portion of Southeastern Alberta. Areas between Oyen and Standard over to Gleichen and Vulcan including Picture Butte and Wrentham and everything in between is included in this area. This includes Brooks and Medicine Hat. The main threats in this region include an isolated tornado or two, large hail between 3 and 5cm and damaging winds between 90 and 110km/h. Isolated gusts towards 120km/h can't be ruled out as these storms merge and 'bow'. The best risk of a tornado will be along the Saskatchewan border.

We have highlighted a 'moderate' risk for severe thunderstorms in yellow or marked with a '3'. This includes a large portion of Southern Alberta including everything between Carway, High River, Calgary, Olds, Red Deer, Halkirk, and Compeer. This includes Drumheller, Red Deer, Calgary, and Lethbridge. The main threats in this area include large hail between 2 and 4cm and damaging winds between 80 and 110km/h. Isolated flooding may be possible, especially north of Calgary due to multiple storms tracking over the same area.

We have highlighted a 'low' risk for severe thunderstorms in green or marked with a '2'. This includes much of the Foothills extending towards the Saskatchewan border. This includes an area between Waterton Lakes Park and Cochrane extending towards Cline River and Pembina Forks. This area also extends east to include Wainwright, Rochon Sands, Leduc, and Ponoka. This region includes Rocky Mountain House as well. The main threats in this area include large hail between 1 and 3cm and damaging winds between 80 and 100km/h. Isolated flooding may be possible, especially north of Pembina Forks and Leduc due to multiple storms tracking over the same area and an area of system-enhanced rain.

Elsewhere, non-severe thunderstorms are expected in the blue region or the area marked with a '1'.

An isolated severe thunderstorm can be ruled out between Edmonton and Grande Prairie, but, the risk is too low to include on the map. Either way, cold-core funnel clouds appear possible in the Grande Prairie for the third day in a row.

Saskatchewan:

Thunderstorm Forecast, for Southern Saskatchewan. Issued June 27th, 2019.

In Southern Saskatchewan, we are watching the risk for thunderstorms to move into the province from Southern Alberta. Most of these thunderstorms will be part of a line or a bowing segment but a few isolate pre-line and post-line cells may be possible.

We have highlighted a 'strong' risk for severe thunderstorms in orange or marked with a '4'. This includes a large portion of Southwestern Saskatchewan. Areas between Kindersley and Elrose extending south towards Lucky Lake, Chaplin and Courval can expect some severe thunderstorms. This includes Grasslands Park, Swift Current and Cypress Hills Park. The main threats in this region include an isolated tornado or two, large hail between 3 and 5cm and damaging winds between 90 and 110km/h. Isolated gusts towards 120km/h can't be ruled out as these storms are in a bowing segment. If cells remain isolated, especially near the Alberta border, an isolated tornado threat will develop.

We have highlighted a 'moderate' risk for severe thunderstorms in yellow or marked with a '3'. This includes a large portion of Southern Saskatchewan including everything between Plenty and Davidson including Emerald Park and Stoughton. This includes Regina, Moose Hay and Estevan. The main threats in this area include large hail between 2 and 4cm and damaging winds between 80 and 110km/h.

We have highlighted a 'low' risk for severe thunderstorms in green or marked with a '2'. This includes a thin portion of the province which extends from Alberta to Manitoba. This includes an area between Macklin and Unity through Dundurn, Fort Qu'Appelle and Carlyle. This includes Oxbow. The main threats in this area include large hail between 1 and 3cm and damaging winds between 80 and 100km/h.

Elsewhere, non-severe thunderstorms are expected in the blue region or the area marked with a '1'.

Manitoba:

Non-severe thunderstorms are expected across the southwestern portion of the province, therefore, a forecast map has not been made. There is a low risk for isolated severe thunderstorms in the Virden-Melita-Turtle Mountain Park region, but, the risk is too low to include in a forecast map.