Figure 1 shows the surface observations at 4:00 pm CDT, which shows a low pressure system over northern Manitoba with a trough of low pressure extending south across southern Manitoba. This trough became the focus for thunderstorms in the evening hours of July 20th, which ultimately led to this tornado.

According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 6:20 pm CDT near St. Norbert, 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 21Z Sat Jul 20 1996. 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/