Severe weather threat to end the heat and humidity. Cooler weather on the way for early week.

Heat and humidity continue to affect a large portion of southern Manitoba including the city of Winnipeg, as a result a heat warning is in place for a large portion of southern Manitoba. A cold front is expected to slice into this heat and humidity and provide relief, but not before storms. 

A heat warning is in place for the large majority of southern Manitoba and into NW Ontario please take as many precautions as you can to make sure you stay as cool as possible, drink water, stay in the shade and wear light clothing. Areas of western Manitoba to the Ontario border are also in a severe thunderstorm watch. There is a high concern though as we get into the late afternoon towards the evening within the next hour, severe thunderstorm development is likely as a cold front slides into the hot and humid airmass. CAPE values in excess  of 2,000-3,000 J/Kg, LI’s of -5 to -9 will make for explosive thunderstorm development with dewpoints between 17 and 21C sufficient moisture should be there to sustain storms as they continue to form. Shear will be a concern with shear in the order of 40knots, and veering in some areas with wind from the east there is a chance for storms with tornadoes. The trigger will finally be the cold front that will be moving into the soupy environment. 

As a result expect severe thunderstorm development to continue as the front slices into the hot and humid airmass, super cells are likely in initial stages of development there will be a risk of heavy rain, wind gusts up to 120km/h, , hail up to golf ball or baseball sized hail. There is a risk of tornadoes as these storms move east into the Red River Valley, there is a chance Winnipeg may be affected by these supercellular storms as well. I will monitor this as the evening goes on. Once storms organize (depending on how Far East before they line out) expect a squall line with multiple bowing segments to move east into the eastern portions of southern Manitoba. Wind gusts over 100km/h, hail up to golf balls and torrential rains will be possible. Once the cold front moves east into Ontario, cooler calmer conditions will set in with a nice NW Flow. 

Cooler and more seasonal temperatures will take over for the beginning of the week with highs in the low to mid 20’s. Rain and storm chances return late week. Enjoy the cooler weather when it comes! -Mike