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Meteorology  Tornadic activity  Tornado alley

Tornado Vortex Signatures in Doppler radial velocity patterns
The most important phenomena associated with severe convection are tornadoes. When a tornado is present, it is usually small enough that it fits within one or two beam widths.

Tornado climatology
Oldest known photograph of a tornado, 1884.
The United States experiences by far the most tornadoes of any country, and has also suffered the most intense ones.

'Tornado alley' claims average 80 lives every year
The plains of the central United States are no strangers to tornadoes.

The tornado picture below is said to be the oldest known photo of a twister. It was taken 22 miles southwest of Howard, South Dakota on August 28, 1884. The photographer is unknown.

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.

Tornado: A violently rotating column of air, a vortex, formed in a thunderstorm which is in contact with both the parent cloud and the ground with a diameter between tens and hundreds of metres.

Tornado Family - A series of tornadoes produced by a single supercell, resulting in damage path segments along the same general line.

Tornado Watch- A Tornado Watch outlines an area where large hail and damaging wind threats, as well as the possibility of multiple tornadoes are possible.

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.

A funnel-shaped whirlwind which extends to the ground from storm clouds
Tropics ...

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.

TORNADO A violently rotating column of air in contact with and extending between a convective cloud and the surface of the earth. It is the most destructive of all storm-scale atmospheric phenomena.

Tornado Vortex Signature
An image of a tornado on the Doppler radar screen that shows up as a small region of rapidly changing wind speeds inside a mesocyclone.

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.

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.) ...

Tornado video classics : the ultimate tornado experience. [videorecording] Edited version.
[St. Johnsbury, VT] : Environmental Films, 1994.
1 videocassette [ ca. 90 min] (Caution : some disturbing images) ...

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, ...

Tornado Warning
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.

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.

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 A rapidly whirling funnel-shaped cloud that reaches down from a storm cloud to touch earth's surface, usually leaving a destructive path
Add Cards ...

Tornado Warning - Issued to warn the public, emergency management and other cooperating agencies when a tornado is forecast to occur or is occurring. The warning will include where the storm was occurring and its direction of movement.

TVS- Tornado Vortex Signature
TWEAK- To change slightly. Often in reference to slightly changing MOS output or any other form of model guidance.
UA- Upper Air ...

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 violent rotating column of air, extending from the base of a cumulonimbus cloud to the ground, producing damaging winds up to 300 mph.

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.

Lines of thunderstorms,
Embedded thunderstorms, and/or
Hail greater than or equal to 3/4" in diameter.

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.

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.

A Tornado Watch is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma.

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.

A tornado-like rotating column of fire and smoke created by intense heat from a forest fire or volcanic eruption.

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.

Like a Tornado Warning, the Severe Thunderstorm Warning is issued by your National Weather Service Forecast Office (NWFO).

Gustfront tornado. A small tornado, usually weak and short-lived, that occurs along the gust front of a thunderstorm. Often it is visible only as a debris cloud or dust whirl near the ground. Gustnadoes are not associated with storm-scale rotation (i.

[Slang], a tornado that does not arise from organized storm-scale rotation and therefore is not associated with a wall cloud (visually) or a mesocyclone (on radar).

A tornado-like rotating column of fire and smoke created by intense heat from a forest fire or volcanic eruption.

Watch Cancellation (SEL): This product will be issued to let the public know when either a Tornado Watch or Severe Thunderstorm Watch has been canceled early. It is issued by the Storm Prediction Center (SPC) in Norman, Oklahoma.

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.

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.

Tornadoes may develop from wall clouds attached to the rain-free base, or from the rain-free base itself - especially when the rain-free base is on the south or southwest side of the main precipitation area.

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.

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.

Cyclone - In general use the term cyclone is applied to any storm, especially violent, small scale circulations such as tornados, waterspouts, and dust devils.

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, ...

[Thunderstorms & Tornadoes] [Hurricanes] [Blizzards & Winter Weather] [Clouds] ...

Severe Thunderstorm-Any one of the three conditions must be met. 1) Tornadoes 2) Hailstones larger than 3/4" 3) Wind gusts greater than 58 miles per hours.

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.

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, ...

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.

Fujita Intensity Scale (F-scale) - A scale developed by T. Theodore Fujita for classifring the severity of a tornado, based on the correlation of wind speed with the degree of destruction.

Mesocyclone - A storm-scale region of rotation, typically around 2-6 miles in diameter. The circulation of a mesocyclone covers an area much larger than the tornado that may develop within it.

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, ...

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 ...

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.

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, ...

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.

See also: See also: Storm, Weather, Thunder, Cloud, Thunderstorm

Meteorology  Tornadic activity  Tornado alley

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