Related Research Articles
A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The windstorm is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than 110 miles per hour (180 km/h), are about 250 feet (80 m) across, and travel a few miles before dissipating. The most extreme tornadoes can attain wind speeds of more than 300 miles per hour (480 km/h), are more than two miles (3 km) in diameter, and stay on the ground for dozens of miles.
A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus. They are usually accompanied by strong winds, and often produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may line up in a series or become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, and tornadoes. Some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes a deviation in their course at a right angle to the wind shear direction.
A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. For this reason, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms, supercells are the overall least common and have the potential to be the most severe. Supercells are often isolated from other thunderstorms, and can dominate the local weather up to 32 kilometres (20 mi) away. They tend to last 2–4 hours.
Storm chasing is broadly defined as the pursuit of any severe weather condition, regardless of motive, which can be curiosity, adventure, scientific investigation, or for news or media coverage.
A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud but not reaching the ground or a water surface. A funnel cloud is usually visible as a cone-shaped or needle like protuberance from the main cloud base. Funnel clouds form most frequently in association with supercell thunderstorms, and are the precursor to tornadoes. Funnel clouds are visual phenomena, these are not the vortex of wind itself.
This article describes severe weather terminology used by the Meteorological Service of Canada, a branch within Environment and Climate Change Canada. The article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article. Some terms are specific to certain regions.
The rear flank downdraft or RFD is a region of dry air wrapping around the back of a mesocyclone in a supercell thunderstorm. These areas of descending air are thought to be essential in the production of many supercellular tornadoes. Large hail within the rear flank downdraft often shows up brightly as a hook on weather radar images, producing the characteristic hook echo, which often indicates the presence of a tornado.
Neil Burgher Ward, American meteorologist, was the first scientific storm chaser, and second known storm chaser, developing ideas of thunderstorm and tornado structure and evolution as well as techniques for forecasting and intercept. He also was a pioneering developer of physical models of tornadoes, first at his home, then at the National Severe Storms Laboratory (NSSL). He significantly furthered understanding of atmospheric vortices, particularly the tornado.
Convective storm detection is the meteorological observation, and short-term prediction, of deep moist convection (DMC). DMC describes atmospheric conditions producing single or clusters of large vertical extension clouds ranging from cumulus congestus to cumulonimbus, the latter producing thunderstorms associated with lightning and thunder. Those two types of clouds can produce severe weather at the surface and aloft.
Storm spotting is a form of weather spotting in which observers watch for the approach of severe weather, monitor its development and progression, and actively relay their findings to local authorities.
A satellite tornado is a tornado that revolves around a larger, primary tornado and interacts with the same mesocyclone. Satellite tornadoes occur apart from the primary tornado and are not considered subvortices; the primary tornado and satellite tornadoes are considered to be separate tornadoes. The cause of satellite tornadoes is not known. Such tornadoes are more often anticyclonic than are typical tornadoes and these pairs may be referred to as tornado couplets. Satellite tornadoes most commonly form in association with very large and intense tornadoes.
The Verification of the Origins of Rotation in Tornadoes Experiment or VORTEX are field experiments that study tornadoes. VORTEX1 was the first time scientists completely researched the entire evolution of a tornado with an array of instrumentation, enabling a greater understanding of the processes involved with tornadogenesis. A violent tornado near Union City, Oklahoma was documented in its entirety by chasers of the Tornado Intercept Project (TIP) in 1973 and visual observations led to advancement in understanding of tornado structure and life cycles. VORTEX2 utilized enhanced technology allowing scientists to improve forecasting capabilities to improve advanced warnings to residents. VORTEX2 sought to elucidate how tornadoes form, how long they last and why they last that long, and what causes them to dissipate.
TWISTEX was a tornado research experiment that was founded and led by Tim Samaras of Bennett, Colorado, US. The experiment announced in 2015 that there were some plans for future operations, but no additional information has been announced since.
Howard Bruce Bluestein is a research meteorologist known for his mesoscale meteorology, severe weather, and radar research. He is a major participant in the VORTEX projects. A native of the Boston area, Dr. Bluestein received his Ph.D. in 1976 from MIT. He has been a professor of meteorology at the University of Oklahoma (OU) since 1976.
Storm Riders is a reality television series following two meteorologists as they travel across the Great Plains of the United States in search of thunderstorms. Storm Riders was seen on The Weather Channel.
During the early evening of Friday, May 31, 2013, a very large and powerful tornado occurred over rural areas of Central Oklahoma. This rain-wrapped, multiple-vortex tornado was the widest tornado ever recorded and was part of a larger weather system that produced dozens of tornadoes over the preceding days. The tornado initially touched down at 6:03 p.m. Central Daylight Time (2303 UTC) about 8.3 miles (13.4 km) west-southwest of El Reno, rapidly growing in size and becoming more violent as it tracked through central portions of Canadian County. Remaining over mostly open terrain, the tornado did not impact many structures; however, measurements from mobile weather radars revealed extreme winds up to 302 mph (486 km/h) within the vortex; these are the highest observed wind speeds on Earth, ahead of the 1999 Bridge Creek–Moore tornado with slightly higher wind speeds. As it crossed U.S. Highway 81, it had grown to a record-breaking width of 2.6 miles (4.2 km). Turning northeastward, the tornado soon weakened. Upon crossing Interstate 40, the tornado dissipated around 6:43 p.m. CDT (2343 UTC), after tracking for 16.2 miles (26.1 km), it avoided affecting the more densely populated areas near and within the Oklahoma City metropolitan area.
Erik Nels Rasmussen is an American meteorologist and leading expert on mesoscale meteorology, severe convective storms, forecasting of storms, and tornadogenesis. He was the field coordinator of the first of the VORTEX projects in 1994-1995 and a lead principal investigator for VORTEX2 from 2009-2010 and VORTEX-SE from 2016-2017, as well as involved in other smaller VORTEX offshoots and many field projects.
Leslie R. Lemon was an American meteorologist bridging research and forecasting with expertise in weather radar, particular regarding severe convective storms. Lemon is, along with Charles A. Doswell III, a seminal contributor to the modern conception of the supercell which was first identified by Keith Browning, and he developed the Lemon technique to estimate updraft strength and thunderstorm organization also as a continuation of Browning's work.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
The tornado outbreak of November 30 – December 2, 2018 was a late-season tornado outbreak that occurred across portions of the West South Central states and Midwestern United States. As a potent shortwave trough moved across the southern portions of the country, it was met with ample moisture return and destabilization, resulting in widespread severe thunderstorms that produced damaging winds, hail, and tornadoes. The event began late on November 30 in Oklahoma, spreading east and resulting in one fatality in Aurora, Missouri. Several tornadic supercells moved across portions of Illinois on December 1, and resulted in 29 confirmed tornadoes. This outbreak was the largest December tornado event on record in Illinois history, surpassing the December 1957 tornado outbreak sequence. The most significant tornado of the event was an EF3 that impacted Taylorville, Illinois, damaging or destroying hundreds of structures and injuring 22 people.
References
- 1 2 3 4 "Jon Davies: Bios, Videos, and Photos". TWC Personalities. The Weather Channel. 2009-02-02. Retrieved 2013-06-02.
- ↑ Davies, Jonathan M. (Oct 1993). "Small Tornadic Supercells in the Central Plains". 17th Conf. Severe Local Storms. St. Louis, MO: American Meteorological Society. pp. 305–9. Archived from the original on 2013-06-17.
- ↑ Davies, Jonathan M. (2006). "Tornadoes with Cold Core 500-mb Lows". Weather Forecast. 21 (6): 1051–62. Bibcode:2006WtFor..21.1051D. doi: 10.1175/WAF967.1 .
- ↑ Pietrycha, Albert E.; J.M. Davies; M. Ratzer; P. Merzlock (October 2004). "Tornadoes in a Deceptively Small CAPE Environment: The 4/20/04 Outbreak in Illinois and Indiana". 22nd Conf. Severe Local Storms. Hyannis, MA: American Meteorological Society.