Figure 1 shows the surface observations at 7:00 pm CDT, which shows a cold front exiting Manitoba and an ongoing thunderstorm behind the front near Virden. This thunderstorm was responsible for this tornado in the evening hours of July 6th.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 6:30 pm CDT near Oak Lake Beach, MB. The track and width of the tornado was not documented by ECCC. The tornado caused no fatalities, injuries or property damage.
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 00Z Sun Jul 7 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/