Widespread heavy to severe thunderstorms likely late this evening – continuing into the overnight hours in Southern Manitoba and Southeastern Saskatchewan.
A stationary front this afternoon in Northern Dakota will separate warm, moist air south of the international border, with warm, drier air in Southern Manitoba. Along this front, there is a risk of isolated severe storms in North Dakota this afternoon – staying stateside.
A deepening system out of Rockies will trigger severe thunderstorms stateside and a second, more significant/widespread risk of thunderstorms this evening/overnight.
Environment Canada (PASPC) Thunderstorm Outlook. Valid 12pm Thursday to 6am Friday. Highlighting the risk for severe thunderstorms. Note: these forecast maps are still experimental and are not currently operational on Environment Canadas website.
A second wave which is forecast to develop late in the day, stateside, is the one we are watching closely. Moist and unstable air creeps across the border into Southeastern Saskatchewan and Southern Manitoba this evening. The northern extent of the second wave is expected to cross the international border into Southeast Saskatchewan and Southern Manitoba sometime around midnight.
There is still some uncertainty regarding evolution and timing of this convective complex. Such complexes also known as MCSs or MCCs – Mesoscale Convective Complex; are notorious for producing intense frequent lightning, flash flooding, and damaging to destructive winds. Large hail is also a possibility, during the initial storm development.
The risk moves out of Southeastern Manitoba into Northwestern Ontario pre-dawn Friday into Friday morning.
We will be monitoring the situation attentively into this evening and overnight.