Home > Severe Weather Safety > Thunderstorms
Thunderstorm Definitions and Safety
According to the National Weather Service (NWS), a thunderstorm occurs when an
observer hears thunder, Radar observers use the intensity of the radar echo to distinguish
between rain showers and thunderstorms. Lightning detection networks routinely track
cloud-to-ground flashes, and therefore thunderstorms. Thunderstorms arise when clouds
develop sufficient upward motion and are cold enough to provide the ingredients (ice and supercooled water) to generate and separate electrical charges within the
cloud. The cumulonimbus cloud is the perfect lightning and
thunder factory, earning its nickname, "thunderhead."
Thunderstorms are like nature's heat pumps. At the very top of giant
thunderstorms, air temperatures can sometimes drop to below -100
| Important Definitions You Should Know: | |
| Watch: Conditions are favorable for the development of a severe weather event in or near the watch area. Prepare for the possibility of severe weather. | Warning: A severe weather event is imminent of occurring in the warned area. It is time to take action! Put preparedness plans into action. |
If a warning is issued
for your area you need to move immediately to a substantial building or
shelter. Stay away from windows. If a tornado warning is in
effect move to the lowest floor of your home. Go to an interior room
(such as a closet or bathroom) and cover your head and body.
Back to Thunderstorms and
Associated Weather Phenomena.
References:
By definition, the National Weather Service classifies a thunderstorm as severe
if it contains hail of three-quarter inches or larger, and/or wind gusts of 58
mph or higher, and/or a tornado.
Severe
thunderstorm watches, meaning conditions are suitable for severe thunderstorm
development during the next several hours, are issued for areas several hundred miles on a
side by the NWS Storm Prediction Center in Norman, Oklahoma.
A severe
thunderstorm warning is issued by the local NWS office, usually for a county or
several counties over an hour or so, based on spotter reports or radar indications of
conditions exceeding severe levels. If there is a distinct threat or actual observation of
a tornado, a tornado warning is issued.
Tornadic storms also
produce hail, downbursts, and lightning, and those hazards should be likewise considered.
Are you interested in helping the NWS in
Riverton fulfill its mission of protecting lives and property across western
and central Wyoming? Check out our
spotter training schedule and join the team. Reports from certified
spotters can be of immense help in making warning decisions. These
spotters are also eligible to participate in as an
eSpotter.
Wind
Lightning
Flash Floods
Tornadoes
Hail
Thunderstorms
Martner, Brooks E. Wyoming Climate Atlas, University of Nebraska
Press 1986.
Lyons, Walter A. Ph.D. The Handy Weather Answer Book,Visible
Ink Press, 1997
