Investigators were out on Wednesday looking for specific patterns of damage that would have indicated tornado activity in East Greenwich Township.
Instead, they found evidence of straight-line winds from a macroburst. The NWS said strong macrobursts can cause tornado-force damage.
The Gloucester County macroburst lasted between five and 20 minutes, the NWS said.
Wind gusts exceeded 70 mph in many other parts of the area, with a 75 mph gust reported in Medford, N.J. and a 72 mph gust at the Philadelphia International Airport.
Dramatic cellphone video taken by a volunteer firefighter in Mantua, New Jersey shows the storm moments before it blew the roof off of the firehouse.
"We saw a black sky coming across, shut the doors down and that's when it all hit. We heard a big, loud boom which was our roof coming off the building," said Shawn Layton, Mantua firefighter.
In a matter of seconds, firefighters say a large portion of the roof was blown off by the powerful winds.
The winds scattered everything across a neighbor's backyard including air conditioning and electrical equipment that was on the roof.
Inside, the building was heavily damaged by water that poured in.
"All of our offices, my office, the career training office, our meeting room - everything that we had worked on about a year ago to renovate - is all destroyed," said Chief Brian Hauss, Mantua Fire Department.
Only moments earlier in nearby East Greenwich Township, the storm wreaked havoc through the area.
"It sounded like a freight train was going through our house, really scary, we thought we were gonna lose our roof," said Amy Sena.
"I took off to the basement, it was like a freight train was coming through the house, the whole house was shaking," said Alane Homer.
The line of severe weather toppled trees, shut down roads, cut power and brought mass transit to a standstill.
In Gibbstown, utility poles, power lines and traffic lights were down across Harmony Road.
Many trees snapped and fell. We found two vehicles crushed at one home - one in the front and one in the back.
Storm damage in Gibbstown, NJ. This family lost 2 vehicles. pic.twitter.com/BxI5UzYRbY— Nora Muchanic (@Muchanic6abc) June 24, 2015
"Tree came down across the car, laying on the roof," said Bob Medary of Gibbstown. "It was wild. Never saw the winds that bad in my life."
"It was taking down every tree all around. It sounded like gunshots going off it was so loud, all the trees breaking, snapping," said Bill Cullen.
At the intersection of South School and Troy there were trees down everywhere you looked and fences were knocked down all over.
"It sounded like a freight train," said Jane Barcus. "I was driving home during this, so I missed it by about 10 minutes."
We met two nuns who were inside the convent at St. Michael's Church on Memorial Avenue when winds tore off the roof. A parish employee rushed over to get them out.
"I banged on their door and they came out. I went to get them over to the school because it was lower ground that what they had there," said Jonathan Wishman.
Sister Jerilyn Einstein said she felt "Very lucky. Very Blessed."
The Deptford Mall was also damaged in the storm. A car was flipped over in the parking lot, and damage to a sign and the roof could be seen.
Here's a look at the cars flipped over at the Deptford Mall. pic.twitter.com/qP588Be53q— Chris Sowers (@chris_sowers) June 23, 2015
The Red Cross opened two reception centers in Gloucester County where residents could get food, water, and electricity. They will reopen at 10:30 a.m. Thursday.
The centers are located at the Gloucester County Complex at 1200 N. Delsea, Clayton, NJ 08312 and at the Mt. Royal Firehouse at 5 Mantua Blvd., Mt. Royal, NJ 08061.
The Red Cross said they helped over 200 people at the centers on Wednesday.