Figure 1 shows the surface observations at 1:00 am CDT, which shows a trough with ongoing thunderstorms (marked as ‘R’) in southeastern Manitoba, which ultimately led to this tornado.

According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 1:00 am CDT east of Dominion City, 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 06Z Sat Jul 7 1990. 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/