Advisory: An advisory is issued when a hazardous weather is occurring, imminent or likely. Advisories are for less dangerous conditions than warnings that cause significant inconvenience.
Watch: A watch means weather conditions are favorable for dangerous weather to occur. A watch means the potential or conditions exist for a dangerous weather event.
Warning: A weather warning means that a dangerous weather event is imminent. Immediate action must be taken to protect life and property. People need to take action as soon as possible.
- Severe Thunderstorm Watch: Conditions are favorable for the development of severe thunderstorms in and close to the watch area. A severe thunderstorm contains large damaging hail of 1 inch in diameter or larger, and/or damaging winds greater than 58 mph or greater. Isolated tornadoes are also possible but not expected to be the dominant severe weather event.
- Severe Thunderstorm Warning: A severe thunderstorm is indicated by Doppler weather radar or sighted by spotters. A severe thunderstorm contains large damaging hail of 1 inch in diameter or larger, and/or damaging winds of 58 mph or greater. These warnings are currently issued on a polygonal basis.
- Tornado Watch: Conditions are favorable for the development of severe thunderstorms and tornadoes in and close to the watch area.
Particularly dangerous situation Tornado Watch: Conditions are favorable for the development of severe thunderstorms and destructive tornadoes in and close to the watch area. These watches are occasionally issued, and usually mean that a major tornado outbreak is possible, where the potential for multiple violent (EF-4 and EF-5) tornadoes exists. These watches are usually issued for a larger area by the Storm Prediction Center in Norman, Oklahoma than a regular Tornado Watch, and are usually valid for a longer period of time than a regular Tornado Watch. This type of watch is usually only reserved for forecast "high-end" severe weather events.
- Tornado Warning: Strong rotation in a thunderstorm is indicated by Doppler weather radar or a tornado is sighted by spotters. These warnings are currently issued on a polygonal basis.
Particularly dangerous situation Tornado Warning: A Large tornado has been confirmed to be producing damage and is moving into and through the warned area. It is usually issued as the initial tornado warning or as a complete re-issuance of the previous tornado warning. These may also include wording for a Tornado Emergency.
Tornado Emergency: Sent as a "severe weather statement" or a complete re-issuance of the tornado warning, this is an unofficial, high end tornado warning issued when a violent tornado is expected to impact a heavily populated area. Such warnings have been issued for the 1999 F5 Moore, Oklahoma tornado, the 2007 EF5 Greensburg, Kansas tornado, and the 2011 EF4 Tuscaloosa, Alabama tornado.