Severe Thunderstorm
Severe Thunderstorm Phenomena and Warnings
A severe thunderstorm is a meteorological event characterized by the presence of lightning and its acoustic effect on the Earth’s atmosphere known as thunder. These storms are capable of producing a variety of severe weather events, including large hail, damaging winds, and tornadoes.
Characteristics of Severe Thunderstorms
Severe thunderstorms are defined by the National Weather Service as those that produce one inch (2.54 cm) diameter hail or larger, winds exceeding 58 miles per hour (93 km/h), or tornadoes. One of the most dangerous types of severe thunderstorms is the supercell, which can produce the most intense and destructive tornadoes. Supercells are characterized by a rotating mesocyclone, an area of organized rotation several kilometers up in the atmosphere.
Supercells
Supercells are capable of producing long-lived, rotating updrafts known as mesocyclones. They are typically isolated from other thunderstorms and can dominate the local weather up to 20 miles (32 kilometers) away. Supercells are notorious for producing severe weather, including large hail and tornadoes.
Forecasting and Warnings
The Storm Prediction Center is a key organization responsible for forecasting the risk of severe thunderstorms and tornadoes in the United States. They issue several types of warnings and watches to alert the public about potential severe weather.
Severe Thunderstorm Watch
A severe thunderstorm watch is issued when atmospheric conditions are favorable for the development of severe thunderstorms. This does not mean that severe weather is imminent but indicates that the specific area has an elevated risk for severe weather.
Severe Thunderstorm Warning
A severe thunderstorm warning is issued when a severe thunderstorm has been detected by radar or reported by storm spotters. This warning indicates that severe weather is occurring or is imminent, and immediate action should be taken to protect life and property.
Tornado Watch and Warning
In addition to thunderstorm warnings, there are specific warnings associated with tornado activity. A tornado watch alerts the public to the potential for tornadoes in and around the watch area, while a tornado warning is issued when a tornado has been sighted or indicated by weather radar.
Safety and Preparedness
Preparedness for severe weather is crucial for minimizing risk. The National Weather Service offers guidance on how to prepare for severe weather, including having a weather radio, creating a safety plan, and understanding severe weather terminology.
Dangerous situations, such as those labeled a Particularly Dangerous Situation, require special attention as they highlight the potential for exceptionally severe and life-threatening weather.