Figure 1 depicts the surface observations at 4:00 pm CDT, which shows two low pressure systems and their associated fronts. The complex interaction between the low pressure over Grand Forks and the advancing cold front across southern Manitoba led to the development of thunderstorms, which ultimately led to this tornado.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 3:10 pm CDT near Manitou, MB. The path of the tornado was not documented by ECCC, but its maximum width was 50 metres. The tornado caused no fatalities, injuries or documented property damage.
Sources
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 21Z Sun Aug 8 2004. 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/