Figure 1 depicts the surface observations at 2:00 am EDT, which shows a stationary front in the northeast United States. This front likely became the focus for thunderstorms throughout the early afternoon hours of July 18th, which ultimately led to this tornado.
The Middlesex County, MA F1 tornado of July 18, 1963 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 in Middlesex County near Flat Rock Hill Quarry at 3:20 pm EDT. The tornado travelled for 1 mile and had a maximum width of 50 yards.
NOAA Central Library. (2019). U.S. Daily Weather Maps. Tuesday July 18, 1963 [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/