Tornado watch or tornado warning
A watch means be ready. A warning means act now.
Tornado watch
The Storm Prediction Center in Norman, Oklahoma issues a tornado watch when the atmosphere over a region can produce tornadoes in the next several hours. Watches are big: often a few dozen counties across parts of two or three states, typically for four to eight hours. Nothing may be happening yet when it is issued. A watch labelled "particularly dangerous situation" means forecasters expect several strong tornadoes.
During a watch: know where you will shelter and how long it takes to get there, keep your phone charged, keep shoes by the door, and check the map now and then. If you are driving or outdoors, plan where you would go.
Tornado warning
Your local Weather Service office issues a tornado warning when a tornado is happening or about to happen. Warnings are small shapes drawn along a single storm's path, usually covering 30 to 45 minutes. If you are inside the shape, go to shelter. More on what a warning means and how much time you get.
Side by side
| Watch | Warning | |
|---|---|---|
| Means | Tornadoes possible | Tornado happening or imminent |
| Issued by | Storm Prediction Center | Your local Weather Service office |
| Covers | A large region, many counties | A shape along one storm's path |
| Lasts | Usually 4 to 8 hours | Usually 30 to 45 minutes |
| Do | Plan, stay alert | Go to shelter now |
Severe thunderstorm watches and warnings work the same way, for hail and damaging wind instead of tornadoes.