Several rounds of thunderstorms are expected across southern Manitoba over the next 24hrs (see loop above). The first round will come tonight into tomorrow morning, bringing the main threats of heavy downpours and strong winds. Stronger storms are expected to develop Sunday afternoon into the evening hours across Manitoba and North Dakota. Two scenarios are possible:
More isolated storms develop across southern Manitoba in the afternoon hours as supercells with large hail, damaging winds and tornadoes could be possible;
Storms develop in North Dakota and move across southern Manitoba in the evening to overnight time frame with hail and damaging winds becoming the primary threat.
The scenario that unfolds will ultimately be decided by the morning storms that roll through from the occluding low pressure over Saskatchewan and how long those storms remain across Manitoba. The longer the storms stay in southern Manitoba, the lesser clearing there will be and the longer it will take for the atmosphere to "recover" or become unstable. At this time, scenario 2 is the most likely scenario.
Below is a collection from the PASPC and SPC.
Area(s): Southern Manitoba
Timing: Sunday late afternoon, evening, and overnight
Threats: Wind gusts to 110 km/h, hail 3-5 cm, and heavy rain
Significant moisture and instability will move into southern Manitoba from the United States on Sunday. While there is a slight chance of thunderstorm initiation in the afternoon hours, it is much more probable for large scale development to occur in the evening hours and/or for thunderstorms to track into the area from North Dakota. Large hail, severe wind gusts, and heavy rain are likely with any well-developed thunderstorm. Most activity looks to move east out of the area overnight, but fast moving upper level disturbances will continue to track into Manitoba from the southwest and will maintain a threat of severe weather into Monday morning.
Below is the U.S. Storm Prediction Center Day 2 outlook, which features an ENHANCED risk of severe weather across eastern North Dakota, northwestern Minnesota and Manitoba: