Following the severe weather outbreak of June 22-24 that included multiple tornado touchdowns and widespread straight-line wind damage, southern Manitoba appears poised for another severe weather event this weekend.

A surface low over western SD and an associated inverted trough stretching NE into southern Manitoba should be the focus for convective development late Sunday afternoon and evening. Latest forecast soundings indicate that steep lapse rates and weak capping due to cooler temperatures aloft will enable convective development along and ahead of the trough to commence with maximum daytime heating, with some thunderstorms becoming severe.

A mid level jet moving eastward over the northern Rockies will produce 0-6 km shear values in the 40-50 kt range, producing a favorable environment for rotating storms, and the possibility of isolated tornadoes from southwestern Manitoba into the northern Dakotas.

Latest GFS model output (00Z) for Sunday afternoon progs MLCAPE values of between 1500 and 2000 j/kg for the region, suggesting that large hail will likely be the main threat with these storms.