Figure 1 depicts the surface observations at 8:00 am EDT, which shows a complex storm system off the east coast of the United States. A stationary front is seen extending across Massachusetts, bringing a lot of precipitation across the northeastern U.S. This front became the focus for thunderstorm activity, which ultimately led to this tornado.

The Florence , MA F3 tornado of September 13, 1971 impacted Hampshire County in Massachusetts. According to NOAA (2019), the F3 tornado caused no fatalities or injuries, but caused $25 thousand dollars in property damage. The tornado touched down near Nonotuck Street at 1:15 pm EDT. The tornado travelled for 0.5 miles and had a maximum width of 7 yards.
Sources
NOAA Central Library. (2019). U.S. Daily Weather Maps. Monday September 13, 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/