A thunderstorm that produces a tornado, winds of at least 58 mph (50knots), and/or hail at least 1" in diameter.
A severe thunderstorm warning is issued when either severe weather is reported by storm spotters or is indicated by radar. The criteria for a storm to become severe includes: Winds of 68mph or greater. Hail of 1" in diameter or greater. A severe thunderstorm warning is issued by your local National Weather Service forecast office. [...]
Severe weather refers to any dangerous meteorological phenomena with the potential to cause damage, serious social disruption, or loss of human life.
A low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms).
A thunderstorm characterized by a single updraft core and a single downdraft that descends into the same area as the updraft cutting off the thunderstorm inflow which in turn causes the updraft and the thunderstorm to dissipate. Although they may briefly be severe, single cell thunderstorms are short-lived, usually lasting about 1/2 hour to an [...]
A Skew-T Log-P diagram is one of four thermodynamic diagrams commonly used in weather analysis and forecasting. It allows straight, horizontal isobars, and provides for a large angle between isotherms and dry adiabats making it easier to read. A Skew-T offers an almost instantaneous snapshot of the atmosphere from the surface to about the 100 millibar [...]
See Storm Prediction Center
Speed shear is the increasing or decreasing of wind speed with height.
A line, either continuous or broken, of active thunderstorms.
An atmospheric state with warm air above cold air which inhibits the vertical movement of air.
Any disturbed state of the atmosphere, especially affecting the Earth's surface, and strongly implying destructive and otherwise unpleasant weather. Storms range in scale from tornadoes and thunderstorms to tropical cyclones to synoptic-scale extratropical cyclones.
The Storm Prediction Center (SPC) is a government agency that is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service (NWS), which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the United States Department of Commerce (DoC). Headquartered at the National [...]
Helicity measured relative to a moving thunderstorm.
Similar to base velocity, storm relative velocity takes the movement of the storm into account when calculating the average velocity of everything in the NEXRAD weather radar beam.
A storm shelter is a type of bunker designed to protect the occupants from violent severe weather, particularly tornadoes. A storm shelter may be underground or an above ground reinforced safe room.
A descending motion of air in the atmosphere occurring over a rather broad area.
See Supercell Thunderstorm
A thunderstorm which contains one quasi-steady to rotating updraft which may persist for several hours. The most dangerous convective storm type.
See Surface-based Convection
Convection occurring within a surface-based layer, i.e., a layer in which the lowest portion is based at or very near the earth's surface.