Figure 1 depicts the surface observations at 12:00 pm MDT.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 12:46 am MDT near Whitecourt, AB. The path and width of the tornado was not documented by ECCC.
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 18Z Tue May 28 1991. 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/