A landspout tornado was confirmed in Mercer County. Here's what that means.

PITTSBURGH (KDKA) -- A landspout tornado happened in Mercer County on Tuesday evening, the National Weather Service confirmed. 

The landspout tornado was recorded at 5:30 p.m. about 1 mile north of the community of New Virginia on the east side of Hermitage.

An EF-U or EF-Unknown rating was assigned because the landspout was confirmed by photo approximation, but currently there are no known damage indicators to assign a further rating. 

Landspouts form when there is a preexisting area of spinning air near the ground that is often induced by some type of boundary causing a change in wind speed or direction in the horizontal. This spinning air is tilted and stretched by a current of rising air, usually underneath a towering cumulus cloud.  

The National Weather Service describes landspouts as "narrow, rope-like condensation funnels that form while the thunderstorm cloud is still growing and there is no rating updraft." The spinning motion on landspouts originates near the ground, the NWS says. 

Unlike landspout tornadoes, traditional tornadoes form from rotating thunderstorms called supercells.