Figure 1 shows the surface observations at 7:00 am CDT, which shows s cold front north of Swan River and extending southwest into Saskatchewan. A warm front is also observed extending eastward across central Manitoba. The cold front became the focus for thunderstorms across western Manitoba, which ultimately led to this tornado.

According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 7:00 pm CDT near Whitefish Lake, 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 00Z Sun Jun 19 1988. 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/