Figure 1 depicts the surface observations at 2:00 am EDT, which shows a stationary front off the U.S. northeast coast. This stationary front likely became the focus for thunderstorms in the late-afternoon and evening hours of July 21st, which ultimately led to this tornado.
The Hampden County, MA F0 tornado of July 21, 1963 impacted Hampden County in Massachusetts. According to NOAA (2019), the F0 tornado caused no fatalities or injuries, but caused $2.5 thousand dollars in property damage. The tornado touched down in Hampden County near Kelly Hill at 6:00 pm EDT. The tornado travelled for 0.3 miles and had a maximum width of 67 yards.
NOAA Central Library. (2019). U.S. Daily Weather Maps. Tuesday July 21, 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/