After flirting with hot and humid the last couple of days, we are now officially into that with Environment Canada issuing Heat Warnings for all of Southern Manitoba. Today and Friday look like they will be the most humid days of the Summer, so far, with it feeling like nearly 40 at times as daytime highs push to 31 to 33 degrees.
"An upper level ridge has been slowly working its way across the northern U.S. Plains and Prairies, and arrives over Southern Manitoba today," explained CMOS Accredited Weathercaster Chris Sumner. "That’s allowing a very warm airmass to push northward, and the combination of southerly winds at the surface, and southwesterly flow aloft, is bringing that moisture. All of that together means hot and humid, and without a doubt feeling like Summer."
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Sumner noted all of this heat and humidity will provide the fuel for potential severe thunderstorm development Thursday afternoon through early Friday morning.
"I’m keeping an eye on the severe thunderstorm potential for late this afternoon into the evening and overnight, primarily for Southwestern Manitoba and the western Red River Valley to start," he said. "A weak disturbance is expected to ride along the top of that atmospheric ridge later today, and that will provide the focus and trigger for those storms. The expectation is those storms will form in southeast Saskatchewan and eastern Montana, and then push westward across Southern Manitoba near the U.S. border as well as northern North Dakota. One thing to note, there are signs in the model runs that there is a slight tornado risk for areas close to the MB/SK border, so that’s something to keep in mind."
Severe risk continues Friday
Friday afternoon and evening may bring more of the same.
"Friday afternoon and evening a cold front will move through the region, ending the brief heat wave we’ll be in, but also providing another possible trigger for severe thunderstorm development, with heavy rain one of the x-factors for that second go around due to slow moving thunderstorm cells," noted Sumner. "Behind the cold front, seasonal temperatures for Saturday, with the forecast models showing cooler than average highs for Sunday."