Touching down at 6:30 pm, this tornado snapped and uprooted trees which crashed down upon and damaged houses.
Figure 1 depicts the surface observations at 8:00 pm EDT, which shows a low pressure system over Lake Huron with a warm front extending into southern Ontario. Figure 1 is more than one hour after the tornado occurred, which leads us to stipulate that storms developed on the northern-advancing warm front, which ultimately led to this tornado.
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According to Environment and Climate Change Canada (2018), an F0 tornado touched down at 6:30 pm EDT near Williamsford, ON. The path and width of the tornado was not documented by ECCC. The tornado caused no fatalities, no injuries or property damage.
Sources
NWS Weather Prediction Center Surface Analysis Archive. (2017). Surface analysis 00Z Wed Jul 9 1997. 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/