A ‘gustnado’ swirled in South Jersey Friday, and a confirmed tornado was stronger than earlier believed, weather service says
Winds up to 105 mph were reported in the gustnado, and up to 95 mph in the tornado.
A “gustnado” — a tornado-like whirlwind more common to the Plains than South Jersey — swirled in Gloucester County on Friday with winds up to 105 mph, the National Weather Service said Monday.
In addition, upon further analysis, a tornado that resulted from a severe storm outbreak and had been verified earlier turned out to be more potent than the preliminary analysis indicated, the agency said.
The gustnado, which traveled about 100 yards in Franklinville, Gloucester County, and snapped the trunks of several hardwood trees, occurred not far from the confirmed tornado, said Zack Cooper, a meteorologist at the National Weather Service office in Mount Holly.
The winds circulated “cyclonically,” he said. However, it was clear that the winds were not tied to any cloud base, and thus were not technically tornadic.
The weather service said that video supplied by a local homeowner showed “trees and branches falling after a rapid wind shift.”
That actual tornado turned out be more vigorous and enduring than had been believed. The preliminary survey results stated that its peak winds were 65 to 75 mph and that damages were confined to the Collings Lakes area of Atlantic County.
Upon further review, investigators determined that peak winds were 90 to 95 mph, and that the twister evidently originated in Williamstown, Gloucester County.
It rated an EF-1 on the Enhanced Fujita scale, the updated version of the damage scale developed by the late Theodore Fujita.
The weather service said it traveled 8.6 miles, with a maximum path of 300 yards. It also took down some trees and snapped a utility pole.
“It probably lifted at points,” Cooper said.
No injuries were reported as a result of the gustnado or the tornado.
Gustnados may occur frequently, said the weather service’s Patrick O’Hara, but given their scale, verifying them is rare.
The survey results were delayed because “we just wanted to make sure the information we got out was accurate,” Cooper said.
The question of whether winds spin or howl in a straight line is more than an exercise in satisfying curiosity, said Sarah Johnson, the warning coordination meteorologist at the Mount Holly office.
Tornado warnings usually are based on radar evidence, and it is important to match that with ground truth.
The weather service maintains a tornado database that is used by researchers and by insurers investigating claims.
Verifications also are important for in-house scorekeeping, matching forecasts against “what actually happened,” she said.
“We have to reach certain goals.”