Figure 1 depicts the surface observations at 8:00 am EDT, which shows a cold front moving through the northeast United States. This front became the focus for thunderstorms throughout the day, which ultimately led to this tornado.

The South Monson, MA F1 tornado of July 17, 1971 impacted Franklin County in Massachusetts. According to NOAA (2019), the F1 tornado caused no fatalities or injuries, but caused $2.5 thousand dollars in property damage. The tornado touched down near Wales Road at 5:50 am EDT. The tornado travelled for 0.5 miles and had a maximum width of 60 yards.
Sources
NOAA Central Library. (2019). U.S. Daily Weather Maps. Saturday July 17, 1971 [PDF]. Retrieved from https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps
NOAA National Centers for Environmental Information (2019). Storm Events Database. Retrieved from: https://www.ncdc.noaa.gov/stormevents/