Meteorologists made that determination after surveying the Newark and Hockessin areas on Tuesday.
The NWS says straight-line winds are thunderstorm winds that have no rotation and therefore are not a tornado.
"One of the things we are looking for is whether trees are blown on top of each other or apart," said Robert Deal, a meteorologist for the NWS. "If they are all blown down in the same direction or away from each other that's more generally straight-line winds."
A path of destruction can be seen from the air, showing snapped trees and damaged homes.
"We're in the White Clay Creek Forest and it's not as simple as saying, 'Oh a couple of trees came down,'" said neighbor Mark Sanford. "This forest came down around this neighborhood and this community."
Two large trees fell onto Sanford's home where he lives with his wife Nancy and 15-year-old dog Ginger in the Lamatan West Neighborhood of Newark, Delaware.
Severe storms bring down trees in Delaware County
"Two huge trees on the back side of the house crisscrossed and came down. Probably 80- to 100-foot trees back there," Sanford said.
Sanford said he was working upstairs in his home office around 6 p.m. Monday when he heard high-pitched winds.
"We ran to the basement and by the time we got to the basement, crashing trees came down around us," Sanford said.
A large portion of the upstairs came crashing down to the first floor.
The entire community is now dealing with extensive property damage.
"Again, the forest is down here," Sanford said. "We're going to need relief, the state, FEMA, something to come in to provide support that insurance is not picking up."
Severe storms bring down trees throughout Delaware Valley region