Knox County under tornado watch tonight. What's the difference ...

As storms move into the area this evening, Knox County and other areas in East Tennessee are under a tornado watch until 2 a.m. April 3, the National Weather Service cautioned.

Strong to severe thunderstorms are possible overnight, bringing damaging wind gusts, large hail and the possibility of tornadoes, the Morristown NWS office warned. The highest risk of severe weather is west of the Interstate 75 corridor.

Other areas of the state were under tornado warnings by 6 p.m.

So what is the difference between a tornado watch and a tornado warning? Here’s how – and why - the National Weather Service differentiates between the two types of alerts.

What does a tornado watch mean?

A tornado watch means residents of the specified area should be prepared because tornadoes are possible in and near the watch area. People should be ready to act quickly if a warning is issued or if they suspect a tornado is approaching, according to the National Weather Service website.

Watches are issued by the Storm Prediction Center for counties where tornadoes might occur, and typically include multiple counties or even states.

What does a tornado warning mean?

A tornado warning means residents should take action immediately and seek shelter, because a tornado has been sighted or indicated by weather radar, threatening imminent danger to life and property.

Warnings are issued by the local forecast office and typically encompass a much smaller area, such as a city or county, that might be impacted by a identified tornado, according to the National Weather Service.

What do severe weather watches and warnings mean?

The National Weather Service defines watches and warnings for thunderstorms or other serious weather events similarly to those listed above for tornadoes,

A watch is announced when the risk of storms or hazardous weather has gone up significantly, though the occurrence, location or timing of it is still uncertain. The intent announcing a watch despite the uncertainty is to provide people with enough lead time to prepare for the weather, the weather service website says.

A warning is issued when a severe weather "is occurring, is imminent, or has a very high probability of occurring" in a particular area, notably for conditions that pose a threat to life or property.