There are several levels of advisory involving tornadoes, but only two are actual warnings. Here they are in order of increasing severity:
- Convective outlook mentioning a risk of tornadoes. (can be issued several days in advance
- Severe weather outlook mentioning tornadoes. (tornadoes may be possible)
- Tornado Watch. (Conditions are favorable for the formation of tornadoes)
- PDS Tornado Watch. (Particularly Dangerous Situation, strong tornadoes are likely)
- tornado warning. (A tornado has been spotted or one may form soon)
- Tornado Emergency. (A large, strong tornado is threatening a populated area)
Note that a PDS tornado watch is a variant of tornado watch, and a tornado emergency is a variant of tornado warning.
