Supercells possible later today in western Manitoba

Today August 25, 2020


Threat level: MEDIUM Confidence: MEDIUM (based on model agreements) Expected hazards: DAMAGING DOWNBURST WINDS // HAIL // A BRIEF TORNADO Locations impacted: in Saskatchewan: Yorkton and surroundings. In Manitoba: Roblin, Russell, Dauphin, Brandon, Neepawa, Carberry, Melita and surrounding areas. Timing: 5pm CDT to 12am CDT Expected watch(s): Severe thunderstorm watches


DISCUSSION: a first round of showers in the early morning hours will impact the forecast area. These showers will stabilize the atmosphere and inhibit further storm development until later in the afternoon, when diurnal heating at the surface will help destabilize the lower-atmosphere and promote convection. For storms to occur later in the day, sunshine will be needed by around noon, or else the atmosphere may not destabilize enough to promote storms. Storms should initiate along the warm front (red in image below) and occluding front (purple in image below). Therefore, storms should initiate near the SK/MB border between Yorkton and Moosomin and rapidly move into Manitoba in the 4-5pm time frame. Storms will be moving southeast and will be fairly isolated in nature, giving the risk for all hazards possible, including tornadoes. The risk is quite conditional and will be re-assessed in the morning.



Environment Canada Forecast



Saskatchewan

  • Area(s): Southeastern and extreme southwestern Saskatchewan

  • Timing: Today and tonight

  • Threats: Wind gusts greater then 90 km/h, hail 3-4 cm, and risk of tornadoes

A trough of low pressure will bring thunderstorms to southeastern Saskatchewan today. Some of these storms may become severe with the primary threat being hail up to golf ball size and a tornado can not be ruled out. Thunderstorms are expected to move into Manitoba during the afternoon and evening. A disturbance from southern Alberta will then move into southwestern Saskatchewan overnight bringing non-severe thunderstorms.


Manitoba

  • Area(s): Southern and central Manitoba

  • Timing: Afternoon through tonight

  • Threats: Wind gusts greater then 90 km/h, hail 3-4 cm, and risk of tornadoes

A trough of low pressure will bring thunderstorms to southern Manitoba today. Some of these storms may become severe with the primary threat being hail up to golf ball size and a tornado can not be ruled out in western Manitoba. Into the evening and overnight hours in southeastern Manitoba the threat will become more of a severe wind and marginally severe hail threat.