A watch: conditions could become severe
A National Weather Service severe thunderstorm watch covers an area where severe storms are possible. It often spans a wide region. Keep checking updates, review your shelter plan and be ready for a warning.
A warning: take action
A warning is issued when severe weather has been observed or indicated by radar. It covers a more specific threatened area. Follow the warning instructions and move into a substantial building.
Read the location and expiry time
Check whether you are inside the affected area, when the alert expires and what hazards it names. Warnings can change as storms move. This website links to official services; it does not issue or reproduce a live warning feed.
Travelling outside the United States
Names and colour systems vary between countries. Do not assume that a colour or an English translation has the same meaning everywhere. Read the explanation from the authority responsible for that country.
Sources & further reading
View the references for this guide
Editorial review: 25 September 2026. Map measurements are updated separately by the provider.