Chaser convention – Originally it referred to serendipitous meeting of chasers in the field akin to "chaser convergence", but now it mostly refers to the National Storm Chasers ConventionArchived 2013-06-22 at the Wayback Machine held annually in the Denver, Colorado area.
Condensation funnel – The area of a funnel cloud or tornado where cloud has condensed. This is not the same thing as a tornado, which is a vortex of wind.
Cyclone An area of cyclonic low pressure, from the scale of an extratropical or tropical cyclone to mesolow to a mesocyclone to a tornadocyclone or even to a tornado. – (slang) Historically, used in the US to a tornado.
DAPPL database – Short for Damage Area Per Path Length, this is one of three US tornado databases and was maintained by Ted Fujita at the University of Chicago including tornadoes from 1916 to 1992.
Diffluence – A pattern of wind flow in which air moves outward (in a "fan-out" pattern) away from a central axis that is oriented parallel to the general direction of the flow. It is the opposite of confluence.[1]
Mini-supercell – A distinct kind of supercell that is smaller than a typical supercell. See low topped supercell.
Mini-tornado – A fallacious term often used in European news media to refer to tornadoes occurring there; even large, strong, and/or long track tornadoes produced by supercells. This is apparently due to the erroneous perception that "real" tornadoes do not occur in Europe (or elsewhere where the term is applied).
Path length (Pl) – The distance a tornado traveled from formation to decay.
Path width (Pw) – The diameter of the tornado vortex winds (not the condensation funnel) capable of causing damage.
Pearson scale (orFujita-Pearson scale) – A tornado rating scale developed by Allen Pearson differentiating path length (P) and path width (P) to accompany NOAA Fujita scale (F) ratings (F-P-P scale).
Power flash – A sudden bright light caused when an overhead power line is severed or especially when a transformer explodes. These can be caused by intense winds (or debris) from tornadoes or downbursts, but the most prominent example occurred in New York City during Hurricane Sandy when its storm surge flooded a Con Ed power plant.
Severe local storm (SLS) – A thunderstorm presenting severe characteristics in a localized area.
Severe Local Storms Unit (SELS) – A team of National Weather Service experts tasked with forecasting convective weather. It was eventually included as a unit within the NSSFC.
Severe thunderstorm (svr) – A hazardous thunderstorm capable of causing injury or damage. The U.S. National Weather Service defines a severe thunderstorm as one producing 58 mph (93 km/h) or greater winds, 1 in (2.5 cm) or larger hail, or producing a funnel cloud or tornado.
Shallow convection – Occurs when convective instability exists, but no convection occurs
Shear – Wind shear – Winds aloft, often measured in knots.
Shear funnel – Brief, often weak funnel generated by shear in a thunderstorm.
Shelf cloud – Generally associated with strong thunderstorms, found along the leading edge. Horizontal and dark in appearance.
Shortwave trough – Embedded kink within seen in overall troughing patterns.
Significant tornado – A substantial tornado, one that is rated F2-F5 or EF2-EF5. Grazulis also includes (E)F0-(E)F1 tornadoes that cause a fatality in his definition for The Tornado Project database.
Significant tornado parameter (STP) – Model parameter calculated using Shear values, Instability values, and vorticity values.
Spin-up – A small, ephemeral vortex. These can refer to tornadoes spawned by quasi-linear convective systems or tropical cyclones, which occasionally become strong and fairly long track. A spin-up may sometimes refer to a landspout or gustnado (the latter of which is rarely an actual tornado).
Storm spotting – The observation of severe weather by individuals trained in weather and reporting. Spotters can be stationary or mobile.
Storm Data (SD) – A National Climatic Data Center (NCDC) publication beginning in 1959 detailing quality controlled tornado and other severe weather summaries as the official NOAA record of such events.
Storm Prediction Center (SPC) – The NWS national guidance center that issues tornado, severe thunderstorm (straight-line wind and hail), and wildfire forecasts.
Storm scale
Storm Track (magazine) (ST) – A science and hobby magazine on storm chasing published from 1977 to 2002.
Stovepipe tornado – (slang) Storm chaser slang for a large cylindrically shaped tornado resembling a stovepipe.
Tornado Alley – A colloquial term referring to regions where tornadoes are perceived as striking more frequently than other areas. It may also be referred to as a tornado belt, especially when describing smaller areas.
Tornado climatology – The study of geographical and temporal distribution of tornadoes and causes thereof.
Tornado couplet – A primary cyclonic tornado and secondary anticyclonic tornado pair.
Tornado emergency – Enhanced wording used by the U.S. National Weather Service in a tornado warningorsevere weather statement when a large, intense tornado is expected to impact a highly populated area (traverse a large city or dense suburbs).
Tornado family – A series of tornadoes spawned by successive (low-level) mesocyclones of the same supercell thunderstorm in a process known as cyclic tornadogenesis. Multiple such supercells occurring on the same day in a common region results in a corridor outbreak of tornadoes.
The Tornado Project (TP) – A concerted research effort from the 1970s-1990s by Thomas P. Grazulis that compiled tornado information for risk assessment. TP published exhaustive accounts, tabulations, and analysis of all known significant tornadoes in the US from 1680 to 1995, which comprises one of three tornado databases.
Tornado pulse
Tornado rating – A subjective integer value assigned to a tornado differentiating its intensity (or path length or width), typically as a proxy inferred by damage analysis.
Tornado watch (TOAorWT) – A forecast that atmospheric conditions within a designated area are favorable for significant tornado activity over the next 1–6 hours (colloquially referred to as red box).
Tornado warning (TOR) – A tornado is occurring or is imminent as one is sighted or is suggested by radar.
Tornadocyclone – The parent circulation of a tornado. This may refer to a low-level mesocyclone.
Tornadogenesis – The process leading to tornado formation.
Tornadolysis – The process leading to tornado decay and death.
Weatherwise – A photographically adorned general interest weather magazine that frequently publishes articles on tornadoes and other severe weather.
Wedge tornado – (slang) Storm chaser slang for a very large tornado. Typically a wedge tornado is defined as one that is wider at ground level than it is tall (from ground to cloud base).
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