Changes in temperature caused by the expansion (cooling) or compression (warming) of a body of air as it rises or descends in the atmosphere, with no exchange of heat with the surrounding air.
The transport of an atmospheric property such as temperature or moisture by wind.
The flat, spreading top of a cumulonimbus cloud, often shaped like an anvil. Thunderstorm anvils may spread hundreds of miles downwind from the thunderstorm itself, and sometimes may spread upwind.
The whole mass of air that surrounds and is bound to the Earth.
See Backing Winds
A counterclockwise shift in wind direction with time or height.
Base Reflectivity is the default NEXRAD weather radar image. Taken from the lowest (½° elevation) slice, it is the primary image.
The average velocity of everything in the volume of NEXRAD weather radar beam.
(slang) A region of storm-scale rotation, in a thunderstorm, which is wrapped in heavy precipitation. This area often coincides with a radar hook echo and/or mesocyclone, especially one associated with an HP storm. The term reflects the danger involved in observing such an area visually, which must be done at close range in low visibility.
A layer of relatively warm air aloft, usually several thousand feet above the ground, which suppresses or delays the development of thunderstorms. Air parcels rising into this layer become cooler than the surrounding air, which inhibits their ability to rise further and produce thunderstorms. Sometimes called the lid.
Convective Available Potential Energy. CAPE is directly related to the maximum potential vertical speed within an updraft; higher values indicate greater potential for severe weather.
A local region of clearing skies or reduced cloud cover, indicating an intrusion of drier air on a severe thunderstorm; often seen as a bright area with higher cloud bases on the west or southwest side of a wall cloud. A clear slot is believed to be a visual indication of a rear flank downdraft (RFD).
The generally prevailing weather conditions of a region over a period of years. Some elements of climate include average high temperatures for a particular day or normal precipitation for a month or season.
The Climate Prediction Center (CPC) is one of the National Centers for Environmental Prediction, which are a part of NOAA's National Weather Service. It is located in College Park, Maryland. CPC issues climate forecasts valid weeks and months in advance.
The scientific study of climates; the science that deals with climates and/or climate conditions and their phenomena
A zone separating two air masses, of which the cooler, denser mass is advancing and replacing the warmer.
The composite reflectivity is the maximum dBZ reflectivity from any of the reflectivity angles of the NEXRAD weather radar
The transport of heat and moisture by the movement of a fluid; In meteorology, the term is used specifically to describe vertical transport of heat and moisture in the atmosphere, especially by updrafts and downdrafts in an unstable atmosphere. Cumulonimbus, towering cumulus clouds and alto-cumulus castellanus clouds are all visible forms of convection. Convection is [...]
A forecast containing the area(s) of expected thunderstorm occurrence and expected severity over the contiguous United States, issued several times daily by the SPC. The terms marginal, slight risk, enhanced risk, moderate risk, and high risk are used to describe severe thunderstorm potential. Local versions sometimes are prepared by local NWS offices.
Tending to move toward one point or to approach each other. Convergence in a horizontal wind field indicates that more air is entering a given area than is leaving at that level. Convergence at low levels may result in upward forcing; at higher levels convergence may result in downward forcing. When other factors such as [...]