A tornado watch has been issued for Long Island and New York City, the National Weather Service said on its website Saturday.
The watch was issued at 8:12 p.m. and is in effect until 5 a.m. It covers Nassau, Suffolk and all of New York City, as well as Rockland and Westchester counties.
Tornado watches are standard in hurricanes, the weather service said.
A upgraded tornado warning was issued for Nassau County from 4 to 4:15 a.m.
"The tornado is associated with the outer bands of the hurricane, and as the hurricane gets near we are getting into the heavier outer bands," said meteorologist Tim Morrin of the National Weather Service in Upton.
If a tornado forms, it will be part of the current weather system and will not change the outlook, Morrin said. "You can't really look at it as a separate phenomenon," he said.
A watch means there is the possibility of a tornado. A warning means a tornado has already formed.
Earlier Saturday, an apparent tornado heavily damaged five homes near Sandbridge, Va., The Associated Press reported.