Southern Manitoba will experience one last blast of warm and humid air before a cooler more stable weather pattern takes hold. Let’s get down to the details. A trough of low pressure will enter southern Manitoba tonight bringing with it another severe weather threat for the province of Manitoba tomorrow. As I say this I am not a professional but a experienced weather specialist. This system will be supplying moisture from the gulf of Mexico allowing for dewpoints to climb into the high teens or low 20s tomorrow afternoon and temperatures from 24 to 27C making it feel closer to the mid 30s. With CAPE values potentially reaching 2,000 to 4,000 JKg tomorrow and lifted indices between -5 to -10 there will be the potential for moderate to explosive development and it should be enough to maintain storms when and if they do develop. A little more complicated but I'll try and explain it, looking at shear for storm maintenance and organization, it definitely isn't lacking. Supercell composite parameter is anywhere between 4-10 meaning, the highest in the red river valley, EHI of 2 to 7, Storm Relative Helicity of 200 to 400 around 10pm, and 20 to >60knots of Bulk Shear.. The trigger will be a cold front entering southern Manitoba with a trough in the jet stream as the front slices into the upper level ridge.
Based on model consensus I think that during the morning timeframe to afternoon there will be an area of storms trailing the warm front , that may end up missing the red river valley completely. They will pose a risk for heavy rainfall and small to moderate size hail. They should clear the North by the late afternoon. The areas further south in the warm sector may heat up substantially to allow for what looks like there may end up being a area of supercell development in the southwest portion of Manitoba into the red river valley , once these storms grow they may decide to travel in there own direction if there is not much in the way of organization but if they do choose to organize into a squall
line the potential would exist for wind gusts in excess of 90 to 100km/h, hail to the size of toonies or golfballs. There would also be a concern for tornadoes IF there is enough clearing in the afternoon, based on EHI readings supercells could support weak to strong tornadoes. Once storms organize into a line I believe there will be a risk for flooding if storms train over the same area for a long time, and
if those areas have been hit by multiple storms before the main batch in the evening. I’m concerned about the areas in the inter lake especially. Please keep an eye out for watches and warnings as the day progresses. We at Manitoba weather centre will keep you informed of any alerts. Once storms move through a cooler more stable airmass will take place for the weekend with temperatures closer to the normal of 14-17C, and overnight lows in the mid to high single digits.
