Tornado Emergency: Significant damage and a high likelihood of numerous fatalities is expected with a large tornado. Immediately seek shelter!
Tornado Warning: A tornado or funnel cloud has been spotted, or there is radar indications of a tornado. Immediately seek shelter!
Tornado Watch: Conditions are right for a tornado to form. Monitor weather information, and review your tornado safety plan.
Severe T-storm Warning: A thunderstorm is producing large hail, damaging winds or both. Stay indoors and away from windows.
Severe T-storm Watch: Conditions are right for severe thunderstorms to form. Monitor weather information.
Advisories: A certain type of weather is likely to occur and impact travel. Monitor weather information.
(Sources: Wikipedia, FOX Carolina Weather)