(CNN) -- An EF1-scale tornado briefly touched down Thursday in Bridgeport, Connecticut, knocking out windows and ripping signs and awnings off buildings, the National Weather Service confirmed Friday.
With winds at an estimated 100 mph, the twister took only about five minutes to cause the damage in downtown Bridgeport, eyewitnesses said.
The areas affected included several streets near Interstate 95, the National Weather Service said.
"In seconds it just turned black, and you can't see across the street. There was foggy, crazy hard rain," said eyewitness Beth Bowman, who was in a downtown bookstore when the twister barreled through.
After five minutes of darkness, the weather cleared and the sun came out, Bowman said. The damage from the brief but powerful storm included uprooted trees and overturned U.S. postal boxes, she said.
The Bridgeport Police Department said the storm caused significant damage.
CNN Radio's Matt Cherry and CNN's Kristen Hamill contributed to this report.