Figure 1 depicts the surface observations at 8:00 am EDT, which shows a cold front moving across the northeast United States. This front became the focus for thunderstorms and ultimately this tornado in the overnight hours of July 11th.
The Townsend , MA F1 tornado of July 11 , 1970 impacted Middlesex County in Massachusetts. According to NOAA (2019), the F1 tornado caused no fatalities or injuries, but caused $25 thousand dollars in property damage. The tornado touched down near Townsend at 3:15 am EDT. The tornado travelled for 0.1 mile and had a maximum width of 50 yards.
Sources
NOAA Central Library. (2019). U.S. Daily Weather Maps. Saturday July 11 8, 1970 [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/