EF1 tornado in Barnstable County, Massachusetts

The same supercell storm that produced the Barnstable-Yarmouth tornado went on to touch down again near the center of Harwich, MA at 1210 PM EDT (1110 AM EST). The initial touchdown was just east of Harwich Elementary School, just south of Parallel Street. It moved northeast through Harwich Center, passing just south of a golf course, and lifted in East Harwich in the Vicinity of Queen Anne Road. At least 150 hardwood trees were either uprooted or snapped. A few homes also had shingles that were ripped off. Wind gusts were estimated as high as 110 mph, which is on the high end of the Enhanced Fujita EF-1 ranking. Harwich spent $1.2 million on cleanup of roads. That figure is estimated to be one-third of the total costs, when individual homeowner claims are taken into account.

The tornado then lifted. However, severe straight-line wind damage was observed in Chatham. Numerous large trees were uprooted, consistent with 90 mph gusts or greater.

A deep southerly flow of tropical moisture was in place over southeast MA with precipitable water values in excess of 2 inches on the south coast. A frontal wave along the coast provided strong low level convergence and that combined with upper divergence from the right entrance region of a 110 knot upper level jet to produce very severe weather for Cape Cod. Three tornadoes occurred! Prior to these, there had only been three recorded tornadoes since 1950. Outside of the tornado area, damage surveys showed that strong microburst winds caused straight-line damage.