Figure 1 shows the surface observations at 4:00 pm CDT, which shows a low pressure system in Saskatchewan with an occluded front extending east across Manitoba and a cold front extending south across Montana. A prefrontal trough is observed moving southeastward across southwestern Manitoba as well. This prefrontal trough triggered thunderstorms, which moved through Brandon and ultimately spawned this brief F0 tornado.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 4:00 pm CDT in Brandon, 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 21Z Mon Aug 10 1987. 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/