When severe weather strikes, the FOX Weather team provides coverage of these storms as they unfold. Here is a guide of some of the words you may hear our meteorologists say while talking about severe weather.
They grow from the ground when the sun heats up the surface of one spot more than another, causing air to rise quickly. Different wind speeds at different altitudes may cause the rising column of air to spin. The rotating column then picks up dirt and debris along the surface.
Even though they may not be classified as a tornado, dust devils can still do damage.
A forming tornado is called a funnel cloud before it hits the ground. Once the funnel touches down, it is called a tornado. Not all funnel clouds become tornadoes.
When a hook echo is seen on the radar, it is an indication that a tornado is likely associated with a thunderstorm. This is one of the signatures that helps provide meteorologists with "radar confirmation" of a tornado.
Landspouts occur when winds at the surface collide. They will begin to make their own vortex, and then a developing thunderstorm passes overhead.
Updrafts from the passing thunderstorm will pull this rotating vortex skyward, giving it a tornado-like appearance.
A tornado with two or more condensation funnels at the same time is a multi-vortex tornado. They also often rotate around a common center or parent circulation or each other. These tornadoes can be especially damaging, according to the NWS.
Particularly Dangerous Situation
The NWS will issue a Particularly Dangerous Situation (PDS) Watch or Warning to highlight a significant threat of severe weather.
"PDS Tornado Watches are issued when the forecaster has high confidence that multiple strong (EF2-EF3 on the Enhanced Fujita Scale) or violent tornadoes (EF4-EF5 on the Enhanced Fujita Scale) will occur in the watch area," FOX Weather meteorologist Greg Diamond said. "There is no specific criteria to issuing one. It is at the discretion of the forecasters at the Storm Prediction Center."
A tornado is a violently rotating column of air that drops from a cloud and touches the ground. It forms within a supercell thunderstorm due to the up and downdrafts creating wind shear (wind that changes directions or speed with height) and starts the column spinning.
Tornadoes can occur year-round, but the most likely time for outbreaks is in the spring, with a second tornado season in the fall.
Tornadoes can occur anywhere in the world.
Twisters are more common across the U.S., from the Plains to the Appalachians. An area between the Great Plains and the Midwest was nicknamed "tornado alley" by two Air Force weather officers stationed in Oklahoma in 1948.
Cold dry air from the Rockies mixes with warm dry air from Mexico and warm moist air from the Gulf of Mexico. The combination can sometimes create severe thunderstorms and tornadoes.
The NWS rarely issues a Tornado Emergency when there is a, "severe threat to human life and catastrophic damage are imminent or ongoing," from a confirmed tornado.
"The way we need to think of it is an enhanced tornado warning, the National Weather Service calling extra special attention to this cell, and its potentially dangerous tornado on the ground, said Brigit Mahoney on FOX Weather.
A tornado outbreak is generally a cluster of tornadoes occurring in the same period of time. NOAA calls it 10 or more tornadoes from a single, organized weather system. Here is how a tornado outbreak happens.
Watches and warnings
The NWS issues advisories, watches and warnings. A watch means that conditions are right, for example, for tornado formation. If a tornado is imminent or on the ground a Tornado Warning is issued.
You can set up notification alerts on your FOX Weather app. to be alerted no matter where you are.
A waterspout is a rotating column of wind over the water. It can be tornadic and drop from the cloud. If a tornadic waterspout makes landfall, it is called a tornado.
A fair-weather waterspout forms at the water and stretches up to a cloud similar to the way a dust devil forms on land.