Severe thunderstorm watch
A severe thunderstorm watch (SAME code: SVA) is a statement issued by weather forecasting agencies to advise the public that atmospheric conditions in a given region may lead to the development of severe thunderstorms within (or near) the region over a period of several hours. The criteria for issuing a watch varies by country, and may also include torrential rainfall and tornadoes.
Source: Wikipedia — Severe thunderstorm watch (CC BY-SA 4.0)