Significant heat and severe weather on the way Today.

Significant high temperatures and humidex readings will be continuing to effect a large portion of southern Manitoba through the day Saturday and into early Sunday. A cold front sliding into the airmass could make for volatile weather that will flush out the heat and humidity. 

03Z HRRR showing the High humidex readings for much of southern Manitoba and the eastern Prairies. (Dew point and Temperature combined, to create feel like temperatures).

Southern Manitoba is in for a interesting day Saturday heat and humidity will continue to build into the region ahead of a cold front that will be entering areas of the Red River Valley in the evening. Heat warnings are in effect for a large portion of southern Manitoba as the hot and humid airmass is in place. Temperatures in the mid 30’s with dewpoints in the mid 20’s are making humidex readings feel close to the mid 40’s. People are advised to stay inside and keep as cool as possible, if you are to go outside please stay as hydrated and seek shade as much as possible!! The vulnerable including the elderly, children and homeless people are advised to take extra precautions to avoid heat stroke. A cold front will be going through this hot and humid air mass this evening and with it significant severe weather is possible. Looking at the severe weather indicies the moisture we have dewpoints in the low to mid 20’s, Humidex readings in the low 40’s. CAPE of 3,000 to 6,000 J/Kg, Lifted index’s of -9 to -12, and shear on the order of 10 to 40 Knots. The trigger this evening will be the cold front moving east across the Red River Valley into Southeastern Manitoba. There is a weak cap in place this evening in southeastern portions of Manitoba and as the cold front moves east the cap is expected to weaken. Severe thunderstorm development may occur east of the city of Winnipeg this evening if the front moves east fast enough, also depending on the cap. Considering most models will have the cap eroding around 21z (4pm-7pm) in the Red River Valley and east supercell storms may have a window to form within that timeframe. However most models show storms not developing until the front gets to the southeastern portion of Manitoba into NW Ontario by 8pm. Regardless once storms form they will pose a significant risk of becoming supercellular with gusts over 120km/h, Heavy rainfall over 50mm an hour, hail up to the size of golf balls or larger, and potential tornadoes. I’ll continue to update this as needed, in the comments below, on Twitter and Manitoba Weather Centre.

Cooler conditions will arrive for the day tomorrow with temperatures in the mid to high 20’s and humidex readings in the mid 30’s should be with us until mid week, chances at showers and thunderstorms return mid week into late week for us. Stay cool and stay sky aware!