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VORTEX2 Science Glossary
- Condensation funnel
- A funnel-shaped cloud associated with rotation and consisting of condensed water droplets (as opposed to smoke, dust, debris, etc.).
- Convective initiation
- The birth of a thunderstorm.
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Cumulonimbus
- A dense cloud that grows upward, looks like a cauliflower, anvil, or tower, and usually has lightning, thunder, and rain.
- Cyclonic
- Counterclockwise turning (in the Northern Hemisphere).
- Doppler radar
- A radar that detects the change in frequency of a signal reflected from moving targets to tell how fast the target is moving towards or away from the radar (velocity). The strength of the signal that bounces back to the radar can tell how heave the rain is (reflectivity).
- Downdraft
- A small-scale column or air that rapidly sinks toward the ground, usually accompanied by precipitation as in a shower or thunderstorm.
- Dryline
- A boundary that separates dry air from moist air.
- EF-Scale
- The Enhanced-Fujita Scale was implemented by the National Weather Service in 2007 to rate tornadoes more consistently and accurately. Damage surveyors consider 28 damage indicators including building type, structures, and trees, then assess the degree of damage. The EF scale ranges from EF-0 to EF5.
- Funnel
- A rotating funnel-shaped cloud extending downward from a thunderstorm base.
- Mesocyclone
- A region of rotation inside the storm, typically between 2–6km in diameter.
- Mesonet
- A network of environmental monitoring stations typically measuring air temperature, rainfall, wind, dew point and humidity, and pressure.
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Mobile mesonet
- An environmental monitoring station attached to a vehicle. V2 will position these vehicles in key areas of a storm.
- Mobile radar
- A radar attached to a flatbed truck. V2 will use up to 10 mobile radars to scan a storm from all angles.
- Rain-free base
- A dark, horizontal cloud base with no visible precipitation beneath it. Typically marks the location of the thunderstorm updraft.
- Reflectivity
- The amount of energy reflected back to the radar by raindrops or other objects.
- Shear
- Winds at two different levels above the ground blow at different speeds and/or in different directions.
- Sounding
- A measurement of atmospheric parameters in a column of air.
- Supercell
- A thunderstorm with a persistent rotating updraft.
- Tornado
- A violently rotating column of air attached to a thunderstorm and in contact with the ground.
- Tornado Alley
- A nickname made up by the media for an area of relatively high tornado occurrence. It does not have definite boundaries.
- Tornadogenesis
- The birth of a tornado.
- Tornado Warning
- Tornadoes have been detected on radar or have been visually identified. The local National Weather Service Forecast Office issues severe weather warnings.
- Tornado Watch
- Conditions are favorable for tornadoes in or near the watch area. Severe weather watches are issued by the NOAA Storm Prediction Center.
- TVS (Tornado Vortex Signature)
- A Doppler radar signature in the radial velocity field indicating intense, concentrated rotation, more so than a mesocyclone.
- Updraft
- A small-scale current of rising air.
- Velocity
- A change of position expressed in terms of speed and direction.
- Vortex
- A spiral motion within a limited area.
- Wall cloud
- An isolated cloud lowering attached to the rain-free base of the thunderstorm.
