Threat of Tennis Ball Hail, Damaging Winds, and Tornadoes on Wednesday as Strong Severe Thunderstorms Take Aim at Parts of Alberta & Saskatchewan

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After a bit of a break yesterday, severe weather returns today to parts of Alberta and Saskatchewan. There is a widespread risk of severe thunderstorms across large swaths of both provinces today, however there is a threat of particularly strong severe thunderstorms for parts of Eastern Alberta and Western Saskatchewan.

The environment will be quite unstable throughout the region today, with CAPE values expected to climb as high as 2500J/kg. Combined with plenty of moisture and a considerable amount of shear, conditions will be favourable for thunderstorm development.

Some storms have already begun this morning to the northwest of Lac la Biche, and the bulk of today’s storms are expected to initiate in the Alberta Foothills later this morning and into the early afternoon. The storms will develop along a warm front that’s associated with a low which will move into Northern Alberta from British Columbia. It’s expected that today’s thunderstorms will start off as small individual storms, but they should quickly grow and strengthen as the track eastward across Alberta and reach the Saskatchewan border by the late afternoon.

Hourly Precipitation at 6pm MDT, courtesy of weatherbell.

The strongest storms of the day are expected to occur during the late afternoon and into the evening, impacting parts of Eastern Alberta approaching the Saskatchewan border and extending eastward as far as Saskatoon. The main risks from these storms will be up to tennis ball sized hail and very damaging wind gusts that could be upwards of 120km/h, however, this area will also have the threat of tornadoes.

As we progress later into the evening and overnight, the storms will continue to track east across Saskatchewan, but they are expected to have weakened slightly. The thunderstorms could end up persisting straight through the night and approach the Manitoba border around sunrise tomorrow.

Simulated reflectivity at 6Am CST, courtesy of weatherbell.

There is a bit of uncertainty associated with today’s thunderstorm risk for Southern Alberta. A few weather models are showing little to no thunderstorm activity in this area and this potential lack of development could be due to the presence of smoke from wildfires in British Columbia. Regardless, the environment in this region will still be primed for thunderstorm development, which is why we have opted to forecast a widespread risk for this region.

Environment Canada has already issued Yellow and Orange level Severe Thunderstorm Watches for much of Central and Southern Alberta and these will likely be extended into Saskatchewan in the coming hours. We will be monitoring today’s thunderstorm development very closely and we will possibly go live later on so be sure to stay tuned!