MANITOBA: Thunderstorm Forecast for Monday, June 19, 2023
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FORECAST DISCUSSION
A complex severe weather situation is in store for much of Southern Manitoba on Monday, extending into Tuesday morning. Throughout Monday, we anticipate the environment for severe weather to gradually build across the region, starting in the afternoon. However, according to current data, storm development is expected to be delayed until the evening, likely initiating in the southwestern part of the province near the Saskatchewan and American border.
That being said, if models are inaccurate and storm development occurs earlier than anticipated, we could be facing a highly volatile situation. Any storm forming in this potent environment would likely rapidly evolve into a supercell, bringing the potential for significantly large hail exceeding the size of golf balls and destructive wind gusts surpassing 115 km/h.
We seriously considered designating a 'significant' risk zone on our map due to the hail threat, but the confidence in early storm development is too low to support such a classification. Therefore, we are maintaining a 'strong' risk level as the highest threat category for this event.
The severe threat will persist into the overnight and early hours of Tuesday as storms traverse the Dauphin, Ashern, and Pegus regions. Although the tornado risk is relatively low in the morning, the possibility of an isolated tornado cannot be ruled out. The primary focus will be on large hail and severe wind gusts.
TORNADO RISK
The tornado risk will largely depend on timing. We have identified an expansive risk zone where the potential for one or two tornadoes is expected later tonight and into the early overnight hours. This risk area stretches from Deep Southwestern Manitoba near the international border through Brandon and up into Dauphin.
Similar to the hail risk, we contemplated upgrading the tornado risk to the 'several' category, but timing presents an issue as many of the storms will form after sunset when there is less energy available. Another concern associated with the timing is the possibility of nighttime tornadoes. This risk will persist throughout the overnight period, although the tornado threat will gradually diminish compared to earlier in the evening.
