This tornado occurred at 7:45 pm, and tore a path through rural properties near the cross-roads community of Rannoch, to the west of St. Marys. It snapped and uprooted trees, flipped a trailer and damaged farm buildings.
Figure 1 depicts a significant ejecting low pressure near Hudson Bay with its associated cold front and warm front at 5:00 pm EDT. Since the tornado occurred at 7:45 pm EDT, storms were likely “pre-frontal” ahead of the cold front, likely initiated by the pre-frontal trough.
According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 7:45 pm EDT near Rannoch, ON. The track and width of the tornado was not documented by ECCC. The tornado caused no injuries, fatalities or property damage.
Sources
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 21Z Tue Jul 18 1990. 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/