Use a NOAA Weather Radio with a tone-alert feature to keep you informed of watches and warnings issued in your area. The tone-alert feature will automatically alert you when a watch or warning is issued.
If planning a trip or extended period of time outdoors, listen to the latest forecasts and take necessary action if threatening weather is possible. Knowing what weather could happen helps you be prepared to respond if necessary. Having a raincoat, umbrella, and disaster supplies kit available will make it easier to deal with severe weather if it occurs.
Watch for tornado danger signs. Tornadoes may happen so quickly warnings can't be issued long in advance. Pay attention to weather clues around you that may warn of imminent danger.
Dark, often greenish sky. Sometimes one or more of the clouds turns greenish (a phenomenon caused by hail) indicating a tornado may develop.
Wall cloud, an isolated lowering of the base of a thunderstorm. The wall cloud is particularly suspect if it is rotating.
Large hail. Tornadoes are spawned from powerful thunderstorms and the most powerful thunderstorms produce large hail. Tornadoes frequently emerge from near the hail-producing portion of the storm.
Cloud of debris. An approaching cloud of debris can mark the location of a tornado even if a funnel is not visible.
Funnel cloud. A visible rotating extension of the cloud base is a sign that a tornado may develop.
Roaring noise. The high winds of a tornado can cause a roar that is often compared with the sound of a freight train.
Tornadoes may occur near the trailing edge of a thunderstorm and be quite visible. It is not uncommon to see clear, sunlit skies behind a tornado. They may also be embedded in rain and not visible at all.
If you live in a single-family home in a tornado-prone area, find out how to reinforce an interior room on the lowest level of your home (such as the basement, storm cellar, bathroom or closet) to use as a shelter. Plans for reinforcing an interior room to provide better tornado protection in your home are available from your local emergency management office or from FEMA.