Tornadoes develop from thunderstorms, most frequently supercell thunderstorms, though they also occur within squall lines and hurricanes. They are believed to be produced when cool air overrides a layer of warm air, forcing the warm air to rise rapidly.
'Tornado alley' claims average 80 lives every year
The plains of the central United States are no strangers to tornadoes. About a thousand occur every year in 'Tornado Alley', killing on average 80 people and leaving a trail of devastation in their wake at a cost of 300 million dollars.
The afternoon of 2 February 1918 was humid and unsettled in Melbourne, with a slow-moving low pressure trough crossing Victoria. As the trough approached, heavy thunderclouds built up. About 4.
Tornado - A violently rotating narrow column of air in contact with the ground and extending from a thunderstorm base. The tornado is most often found in the southwest quadrant of the storm, near the trailing edge of the cumulonimus cloud.
Tornadoes often form in the hot, humid weather of a late spring or summer afternoon. The thunderstorms that produce tornadoes frequently develop in the warm, moist air near the fronts or transition zones between warm and cold air masses.
Tornado: A violent rotating column of air, in contact with the ground, pendant from a cumulonimbus cloud. A tornado does not require the visible presence of a funnel cloud. It has a typical width of tens to hundreds of meters and a lifespan of minutes to hours.
Tornado- a violent, rotating column of air extending from the ground to a thunderstorm.
Trade Winds- easterly-blowing winds that are found on either side of the equator and blow northeasterly in the Northern Hemisphere and southeasterly in the Southern Hemisphere.
tornado: small mass of air that spins rapidly about an almost vertical axis and forms a funnel cloud that contacts the ground. Comes down from a cumulonimbus cloud and is considered probably the most destructive of all weather systems.
(Twister) A violently rotating storm of small diameter; the most violent weather phenomenon. It is produced in a very severe thunderstorm and appears as a funnel cloud extending from the base of a Cumulonimbus to the ground.
The cyclone of the temperate regions, the tornado and the hurricane are all vortex-like low-pressure areas, but of very different character. The temperate cyclone is fed by the energy available at fronts between air masses, covers a large area, and has moderate winds.
Tornado An intense, rotating column of air that protrudes from a cumulonimbus cloud in the shape of a funnel or a rope and touches the ground. (See Funnel cloud.)
Trade winds The winds that occupy most of the tropics and blow from the subtropical highs to the equatorial low.
TORNADO - A violent rotating column of air, usually forming a pendant from a cumulonimbus cloud with the circulation reaching the ground. It nearly always starts as a funnel cloud and may be accompanied by a loud roaring noise.
Tornado alley Region of maximum tornado frequency in North America; a corridor stretching from central Texas northward into Oklahoma, Kansas and Nebraska, and eastward into central Illinois and Indiana, ...
A warning issued by Environment Canada's Meteorological Service (MSC), when at least one tornado is imminent, as indicated by observations, reports and/or radar scans.
Tornado Warning (Marine) ...
tornado (sometimes called cyclone, twister)—A violently rotating column of air, pendant from a cumulonimbus cloud, and nearly always observable as “funnel-shaped.“ It is the most destructive of all small-scale atmospheric phenomena.
Tornado A twisting, spinning funnel of low pressure air. The most unpredictable weather event, tornadoes are created during powerful thunderstorms. As a column of warm air rises, air rushes in at ground level and begins to spin. If the storm gathers energy, a twisting, spinning funnel develops.
Tornado Alley- The area of the United States in which tornadoes are most frequent. It encompasses the great lowland areas of the Mississippi, the Ohio, and lower Missouri River Valleys.
Tornado Watch - Issued when conditions are favorable for the development of severe thunderstorms and possible tornados in and close to a defined area.
Wall Cloud - An area of clouds that extends beneath a severe thunderstorm. If a wall cloud rotates, it might precede tornado development.
Tornado: Extension of the base of a Cumulonimbus cloud, in the form of funnel, which, circulating fast, goes down to the surface of the Earth, where it produces as strong whirlwind capable of causing great destruction.
Tornado- A violently rotating column of air that reaches from the base of a cloud to the ground.
Tropics- The area of the globe from latitudes 23.5 degrees north to 23.5 degrees south.
Tropical Air- Warm, humid air masses that form in tropical regions.
Tornado - It begins as a funnel cloud with spinning columns of air that drop down from a severe thunderstorm. When they reach the ground they become tornadoes. Tornadoes are between 300 and 2,000 feet wide and travel at speeds of 20 to 45 miles per hour.
TORNADO - A region of rotation extending from the base of a thunderstorm or other convective cloud to the earth's surface. This is a vortex, or wind velocity field, with a speed of at least 40 MPH at the surface. Tornadoes depend on a parent cloud, such as a thunderstorm, in order to develop.
A Tornado Watch is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma. Prior to the issuance of a Tornado Watch, SPC will usually contact the affected local National Weather Forecast Office (NWFO) and they will discuss what their current thinking is on the weather situation.
A tornado is a violently rotating column of air in a small range with huge power and extreme damage capability. The diameter of a tornado can range from tens of meters to several hundred meters. In average it is about 250 meters. When seen from afar, it looks like a dark grey funnel or a trunk.
A tornado-like rotating column of fire and smoke created by intense heat from a forest fire or volcanic eruption.
Another name for the initial wind surge observed at the surface as the result of downdrafts forming the leading edge or gust front of a thunderstorm.
All tornadoes, and most other severe local windstorms, are assigned a single number from this scale according to the most intense damage caused by the storm.
Lines of thunderstorms
Large areas of thunderstorms
Severe or extreme turbulence
Duststorms and sandstorms lowering visibilities to less that three (3) miles.
Volcanic Ash ...
Weather Forecast Office(Abbrev. WFO) - this type of National Weather Service office is responsible for issuing advisories, warnings, statements, and short term forecasts for its county warning areaWeatherfaxSee RADIOFACSIMILEWedge TornadoSlang for a large tornado with a condensation ...
Fujita tornado scale Based upon damage patterns, classifies twisters into six categories of wind speed (F0 thru F5), ranging from 40 to 318 mph estimated wind speed, plus a hypothetical F6 with winds from 318 mph to Mach 1. Developed in 1971 by T. Theodore Fujita of the University of Chicago.
Cold-air-funnelA funnel cloud or (rarely) a small, relatively weak tornado that can develop from a small shower or thunderstorm when the air aloft is unusually cold (hence the name). They are much less violent than other types of tornadoes.
When observed from a distance, they are sometimes mistaken for tornadoes. SEA BREEZE A diurnal coastal breeze that blows onshore, from the sea to the land. It is caused by the temperature difference when the surface of the land is warmer than the adjacent body of water.
Note particularly the development of the cloud/s giving rise to the thunderstorm/tornado/waterspout/etc. What we are looking for is the rapidity of build of the cloud; its vertical extent in a noted time. Is it building directly upwards, or sheared to one side?
These may produce some heavy rain, hail, or even a weak tornado, but they are usually short-lived (30 minutes or less). The second type is known as a multicell cluster composed of a group of convective clouds that move together as a single unit.
Wedge (or Wedge Tornado)
[Slang], a large tornado with a condensation funnel that is at least as wide (horizontally) at the ground as it is tall (vertically) from the ground to cloud base. The term "wedge" often is used somewhat loosely to describe any large tornado.
Enhanced wording - An option used by in some tornado and severe thunderstorm watches when the potential for strong to violent tornadoes, or unusually widespread damaging straight-line winds, is considered high.
Listed weather types include tornado, waterspout, funnel cloud, thunderstorm and severe storm, liquid precipitation (drizzle, rain, rain showers), freezing precipitation (freezing drizzle, freezing rain), and frozen precipitation (snow, snow pellets, snow grains, hail, ice pellets, ice crystals).
Doppler radar: weather radar system that employs the apparent shift in frequency of radio waves to perceive air motion and consequently predict tornadoes and precipitation sooner than previous radars, as well as measure the speed and direction of rain and ice.
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counterclockwise (in the Northern Hemisphere) as would be seen from above. Nearly all mesocyclones and strong or violent tornadoes exhibit cyclonic rotation, but some smaller vortices such as gustnadoes occasionally rotate anticyclonically (clockwise). Compare with anticyclonic rotation.
Suction vortices Small, rapidly rotating whirls perhaps 10 meters in diameter that are found within large tornadoes.
Sulfur dioxide (SO2) A colorless gas that forms primarily in the burning of sulfur-containing fossil fuels.
Post-storm Report: A report issued by a local National Weather Service office summarizing the impact of a tropical cyclone on its forecast area. These reports include information on observed winds, pressures, storm surges, rainfall, tornadoes, damage and casualties.
A small whirling storm over water which can either be spawned from the base of a thunderstorm, or formed in a cold outbreak of Arctic air. They are similar, but generally no as severe as tornadoes.
Wave Direction ...
Cyclone A severe tropical storm (i.e., winds >64 knots) in the Indian Ocean and Bay of Bengal. See also Hurricane and Typhoon. The term is also applied to closed circulations in the mid latitudes and also popularly to small scale circulations such as tornadoes.
as commonly used in weather observing practice, an observable occurrence of particular physical significance within the atmosphere; from the viewpoint of weather observations, the atmospheric phenomena include all hydrometeors (precipitation types and fogs), blowing snow, thunderstorms, tornadoes, ...
There is also a special type of Precipitation mode sometimes called "Severe Weather" mode. This mode operates like normal precip mode, but utilizes VCP11 and produces an image about every 5 minutes. This mode is only used for research or for extreme weather events like hurricanes or tornadoes.