A tornado watch was in effect for five North Jersey counties -- including Bergen and Passaic -- until 10 p.m. Friday.
A watch merely means that conditions exist for a potential tornado. It is not considered a warning.
However, the National Weather Service advises that citizens remain alert to the possibility of a warning during a watch.
"Watches are issued by the Storm Prediction Center for counties where tornadoes may occur," the service says. "The watch area is typically large, covering numerous counties or even states."
Warnings typically involve a much smaller area -- and are much more serious.
In those instances, "a tornado has been sighted or indicated by weather radar," the weather service says. "There is imminent danger to life and property.
"Move to an interior room on the lowest floor of a sturdy building. Avoid windows. If in a mobile home, a vehicle, or outdoors, move to the closest substantial shelter and protect yourself from flying debris."
Portions of South Jersey, including Cape May County, were under a tornado warning on Friday. The northern watch area included Essex, Hudson and Union counties.
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