Figure 1 shows the surface observations at 7:00 pm CDT, which shows a low pressure across Saskatchewan with a warm front extending eastward across Manitoba and a cold front extending south. A line of thunderstorms is also observed on the Saskatchewan/Manitoba border. This squall line was responsible for two tornadoes across southern Manitoba on this day.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 10:00 pm CDT west of Grandview, 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 Wed Jun 17 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/