Figure 1 shows the surface observations at 7:00 am CDT, which shows southern Manitoba being generally in an area of fair weather (high pressure). This leads us to believe that a lake-breeze boundary may have set up northeast of Lake Manitoba, which could have led to thunderstorm development in the Interlakes region.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 6:55 pm CDT near Fairford, MB. The track and width of this tornado was not documented by ECCC. The tornado caused no injuries, fatalities or property damage.
NOAA Central Library. (2020). U.S. Daily Weather Maps. Saturday July 26, 1980 [PDF]. Retrieved from https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps
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/