Figure 1 shows the surface observations at 10:00 pm CDT, which shows a trough of low pressure moving across southeastern Manitoba. This trough was responsible for triggering thunderstorms in the evening hours of May 30th, which ultimately led to this tornado.

According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 11:00 pm CDT near Darlingford, MB. The track and width of the tornado was not documented by ECCC. The tornado caused no fatalities, injuries or property damage.
Sources
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 03Z Fri May 31 1991. Retrieved from: https://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive.php
Environment and Climate Change Canada Data. (2018). Canadian National Tornado Database: Verified Events (1980-2009) – Public. Retrieved from: http://donnees.ec.gc.ca/data/weather/products/canadian-national-tornado-database-verified-events-1980-2009-public/