Northern Ontario: Thunderstorm Outlook for Friday, July 23, 2021

Forecast Discussion

There is the potential for significant severe storms through parts of Northwestern Ontario during the afternoon and evening on Friday. The environment is favourable for some quite powerful storms to develop near the Manitoba border northeast of the Kenora area. We’re currently targeting the Red Lake, Dryden and Sioux Lookout corridor for the strongest severe potential but this may shift around a bit depending on how early in the day that we see storm development.

Some models have storms development further east closer to the Armstrong area, but right now we are going with the more western risk zone. These storms include the risk for some very large hail (perhaps golf ball size or even larger), destructive wind gusts over 110km/h and heavy rainfall. There is also the potential for several tornadoes and maybe even an isolated significant tornado somewhere in Northwestern Ontario as outlined in the tornado risk zone on our map.

The storms will continue to track eastward throughout the evening hour bringing the threat of severe weather as far east as Thunder Bay and Geraldton although the main threat will shift towards damaging wind risk. The tornado threat will be mainly during the afternoon and early evening hours, but still can’t rule out an isolated tornado even outside the main risk zone. We should see the severe risk come to an end by midnight although strong non-severe storms will continue into the overnight hours.