Figure 1 depicts the surface observations at 8:00 am EDT, which shows a cold front moving across the Great Lakes. This front moved east-southeast throughout the day and triggered thunderstorms across Massachusetts, which ultimately led to this long-track F1 tornado.
The Lowell , MA F1 tornado of July 1, 1971 impacted Middlesex County in Massachusetts. According to NOAA (2019), the F1 tornado caused no fatalities, but injured one person and caused $25 thousand dollars in property damage. The tornado touched down near Four Corners at 3:45 pm EDT. The tornado travelled for 25.2 miles and had a maximum width of 33 yards.
NOAA Central Library. (2019). U.S. Daily Weather Maps. Saturday July 1, 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/