Figure 1 depicts the surface observations at 2:00 am EDT, which shows a warm front across the northeast United States and a cold front slicing through the Great Lakes. This cold front became the focus for intense thunderstorms through the afternoon hours of June 19th, which ultimately led to this tornado.
The Ponakin Mill, MA F1 tornado of June 19, 1957 impacted Worcester 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 Worcester County over Lancaster State Forest at 4:00 pm EDT. The tornado travelled for 1.8 miles and had a maximum width of 33 yards.
NOAA Central Library. (2019). U.S. Daily Weather Maps. Wednesday June 19, 1957 [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/