 Satellite view of a supercell A supercell is a severe thunderstorm with a deep rotating updraft (a mesocyclone) [1]. Supercell thunderstorms are the largest, most severe class of single-cell thunderstorms. It has been argued that there are really only two types of thunderstorms: supercell and ordinary, though some have four classifications: single-cell, multi-cell, squall line, and supercell. Image File history File links Download high resolution version (1152x720, 516 KB)NOAA false-color image of a tornadic supercell approaching Siren, Wisconsin, USA on June 19, 2001. ...
Image File history File links Download high resolution version (1152x720, 516 KB)NOAA false-color image of a tornadic supercell approaching Siren, Wisconsin, USA on June 19, 2001. ...
A severe thunderstorm is a thunderstorm with winds 58 mph or greater, 3/4 inch or larger hail, or tornadoes. ...
An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ...
This article or section may be confusing for some readers, and should be edited to be clearer or more simplified. ...
A squall or squall line is an organized line of thunderstorms. ...
Supercells are usually found isolated from other thunderstorms, although they can sometimes be embedded in a squall line. Because they can last for hours, they are known as quasi-steady-state storms. Supercells have the capability to deviate from the mean wind. If they track to the right (left) of the mean wind, they are said to be right-movers (left-movers). The majority of long-lived supercells are right-movers within the United States.
Supercells can be any size, large or small, low or high topped. They usually produce copious amounts of hail, torrential rainfall, strong winds, and substantial downbursts. Supercells also produce tornadoes within the mesocyclone, although only 30% or less do so. [2] Look up Hail, hail in Wiktionary, the free dictionary. ...
Rain falling For other uses see Rain (disambiguation). ...
Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earths surface. ...
A downburst is a column of sinking air that is capable of producing damaging straight-line winds over 100 mph, similar to, but distinguishable from tornadoes. ...
Union City, Oklahoma tornado (1973) A tornado is a violently rotating column of air which is in contact with both a cumulonimbus (or, in rare cases, cumulus) cloud base and the surface of the earth. ...
Supercells can occur in many parts of the contiguous United States, however, they are most frequent in the Great Plains and desert states. They can also occur anywhere in the world under the right pre-existing weather conditions. The first storm to be identified as such was the Wokingham storm over England, which was studied by Keith Browning and Frank Ludlam in 1962. [3] The Great Plains is the broad expanse of prairie which lies east of the Rocky Mountains in the United States of America and Canada, covering all or parts of the U.S. states of New Mexico, Texas, Oklahoma, Colorado, Kansas, Nebraska, Wyoming, Montana, South Dakota and North Dakota and the...
Desert view in Saudi Arabia. ...
Location within the British Isles Wokingham is a small town in Berkshire (population 30,403 according to the 2001 census) in the south east of England, close to Reading. ...
Royal motto (French): Dieu et mon droit (Translated: God and my right) Englands location (dark green) within the United Kingdom (light green), with the Republic of Ireland (blue) to its west Languages English Capital London Largest city London Area – Total Ranked 1st UK 130,395 km² Population –mid-2004...
Keith Browning is a British meteorologist who worked at Imperial College, the Met Office and University of Reading department of meteorology. ...
1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar). ...
Anatomy of a supercell The current conceptual model of a supercell was described in Severe Thunderstorm Evolution and Mesocyclone Structure as Related to Tornadogenesis by Leslie R. Lemon and Charles A. Doswell III. (See Lemon technique). The Lemon Technique is a method used by weather radar operators to determine the relative strength of thunderstorm cells in a vertically sheared environment. ...
Supercells derive their rotation through tilting of horizontal vorticity (an invisible horizontal vortex) caused by wind shear. Strong updrafts lift the air turning about a horizontal axis and cause this air to turn about a vertical axis. This forms the deep rotating updraft, the mesocyclone. Vorticity is a mathematical concept used in fluid dynamics. ...
Vortex created by the passage of an aircraft wing, revealed by coloured smoke A vortex is a spinning, often turbulent, flow (or any spiral motion) with closed streamlines. ...
Wind shear jake rinow is the god of technologyis a difference in wind speed or direction between two points in the atmosphere. ...
An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ...
This article or section may be confusing for some readers, and should be edited to be clearer or more simplified. ...
A cap or capping inversion is usually required to form a downdraft of sufficient strength. The cap puts an inverted (warm-above-cold) layer above a normal (cold-above-warm) boundary layer, and by preventing warm surface air from sinking too far, allows one or both of the following: A capping inversion is an elevated inversion layer that caps a convective boundary layer. ...
In physics and fluid mechanics, the boundary layer is that layer of fluid in the immediate vicinity of a bounding surface. ...
- Air below the cap warms and/or becomes more moist
- Air above the cap cools
This creates a warmer, moister layer below a cooler layer, which is increasingly unstable (because warm air is less dense and tends to rise). When the cap weakens or moves, explosive development follows.
In North America, supercells usually show up on Doppler radar as starting at a point or hook shape on the southwestern side, fanning out to the northeast. The heaviest precipitation is usually on the southwest side, ending abruptly short of the rain-free updraft base or main updraft (not visible to radar). The RFD, or rear flank downdraft carries precipitation counterclockwise around the north and northwest side of the updraft base, producing a "hook echo" that indicates the presence of a mesocyclone.
Features of a supercell
 Features of a supercell. Note: This is a typical northwestward view in North America
 Diagram of supercell from above. RFD: rear flank downdraft, FFD: front flank downdraft, V: V-notch, U: Main Updraft, I: Updraft/Downdraft Interface, H: hook echo This "dome" feature appears above the anvil of the storm. It is a result of the powerful updraft. Image File history File links Download high resolution version (1832x1134, 231 KB)Features of a supercell File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Image File history File links Download high resolution version (1832x1134, 231 KB)Features of a supercell File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
World map showing North America A satellite composite image of North America. ...
Image File history File links Supercella. ...
Image File history File links Supercella. ...
An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ...
This area, typically on the southern side of the storm in North America, is relatively precipitation free. This is located beneath the main updraft, and is the main area of inflow. While no precipitation may be visible to an observer, large hail and rain may be falling from this area. It is more accurately called the main updraft area. An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ...
The wall cloud forms near the downdraft/updraft interface. This "interface" is the area between the precipitation area and the precipitation-free base. Wall clouds form when rain-cooled air from the downdraft is pulled into the updraft. This wet, cold air quickly saturates as it is lifted by the updraft, forming a cloud that seems to "descend" from the precipitation-free base. Wall clouds are common and are not exclusive to supercells: Only a few actually produce a tornado. Wall clouds that persist for more than ten minutes, wall clouds that seem to move violently up or down, and violent movements of cloud fragments (scud or fractus) near the wall cloud are indications that a tornado could form. A wall cloud with tail cloud A wall cloud is a cloud formation. ...
Mammatus (Mamma, Mammatocumulus) are bulbous or pillow-like cloud formations extending from beneath the anvil of a thunderstorm. These clouds form as cold air in the anvil region of a storm sinks into warmer air beneath it. Mammatus are most apparent when they are lit from one side or below and are therefore at their most impressive near sunset or shortly after sunrise when the sun is low in the sky. Mammatus are not exclusive to supercells and can be associated with developed thunderstorms and cumulonimbus. Mammatus clouds in Tulsa, Oklahoma, 1973 Cumulonimbus with mammatus formed after Hurricane Catarina in Santa Catarina, Brazil, 2004 Another view of the post-Catarina mammatus formation Mammatus (also known as mamma or mammatocumulus) is a meteorological term applied to a cellular pattern of pouches hanging underneath the base of a...
This is the area of heaviest precipitation. Between the precipitation-free base and the precipitation area, a "vaulted" or "cathedral" feature can be observed. In high precipitation supercells an area of heavy precipitation may occur beneath the main updraft area. An Updraft or Downdraft is refers to the vertical movement of air as a weather related phenomenom. ...
A line of smaller cumulonimbi or cumulus that form in the warm rising air pulled in by the main updraft. Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other bad weather. ...
Radar features of a supercell The "hook echo" is the area of confluence between the main updraft and the rear flank downdraft (RFD). This indicates the position of the mesocyclone. Image File history File links Download high resolution version (700x670, 137 KB)A map of radar reflectivity of a tornadic supercell. ...
Image File history File links Download high resolution version (700x670, 137 KB)A map of radar reflectivity of a tornadic supercell. ...
- Bounded weak echo region (or BWER)
This is a region of low radar reflectivity bounded above by an area of higher radar reflectivity. This is evidence of a strong updraft. An "notch" of weak reflectivity on the inflow side of the cell. This is not a V-Notch. A "V" shaped notch on the leading edge of the cell, opening away from the main downdraft. This is an indication of divergent flow around a powerful updraft.
See also: Radar This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll[1]. Radar is a system that uses radio waves to detect, determine the distance of, and map, objects such...
Supercell variations Supercell thunderstorms are sometimes classified by meteorologists and storm spotters into three categories. However, not all supercells fit neatly into any one category, and many resemble all three at different times during the lifespan of the storm. The standard definition given above is referred to as the Classic supercell. All types of supercells can produce severe weather. Meteorology is the scientific study of the atmosphere that focuses on weather processes and forecasting. ...
SKYWARN is a program of the United Statess National Weather Service (NWS). ...
Low Precipitation
LP supercells contain a small precipitation (rain/hail) core separate from the updraft. This type of supercell may be easily identifiable with "sculpted" cloud striations in the updraft base or even a "corkscrewed" or "barber pole" appearance on the updraft, and sometimes an almost "anorexic" look compared to classic supercells. This is because they often form along dry lines, thus leaving them with little available moisture despite high upper level wind shear. They usually dissipate rapidly rather than turning into classic or HP supercells, although it is still not unusual for them to do the latter, especially if they happen to collide with a much moister airmass along the way. Although these storms usually produce weak tornadoes, they have been known to produce strong ones. These storms can produce large hail even with little or no visible precipitation core, making them hazardous to storm chasers and people and animals caught outside. Due to the lack of a heavy precipitation core, LP supercells can sometimes show weak radar reflectivity without clear evidence of a hook echo, when in fact they are producing a tornado at the time. This is where observations by storm spotter and storm chasers may be of vital importance. Funnel clouds, or more rarely, weak tornadoes will sometimes form midway between the base and the top of the storm, descending from the main Cb (cumulonimbus) cloud. Lightning is rare compared to other supercell types, but it is not unknown and is more likely to occur as intracloud lightning rather than cloud-to-ground lightning. In the United States, these storms almost exclusively form from the Rocky Mountains to the Mississippi River in the spring and summer months. They can occur as far north as Montana, North Dakota and even in the provinces of Alberta and Saskatchewan in Canada. In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ...
NSSL vehicles on Project Vortex. ...
A classic hook echo. ...
SKYWARN is a program of the United Statess National Weather Service (NWS). ...
NSSL vehicles on Project Vortex. ...
A funnel cloud. ...
Union City, Oklahoma tornado (1973) A tornado is a violently rotating column of air which is in contact with both a cumulonimbus (or, in rare cases, cumulus) cloud base and the surface of the earth. ...
Cumulonimbus (Cb) is a type of cloud that is tall, dense, and involved in thunderstorms and other bad weather. ...
White Goat Wilderness Area, Alberta, Canada View of the Rocky Mountains as depicted on the Colorado state quarter The Rocky Mountains, often called the Rockies, are a broad mountain range in western North America. ...
The Mississippi River, derived from the old Ojibwe word misi-ziibi meaning great river (gichi-ziibi big river at its headwaters), is the second-longest river in the United States; the longest is the Missouri River, which flows into the Mississippi. ...
Official language(s) English Capital Helena Largest city Billings Area Ranked 4th - Total 147,165 sq mi (381,156 km²) - Width 255 miles (410 km) - Length 630 miles (1,015 km) - % water 1 - Latitude 44°26 N to 49° N - Longitude 104°2 W to 116°2 W Population Ranked...
Official language(s) English Capital Bismarck Largest city Fargo Area Ranked 19th - Total 70,762 sq mi (183,272 km²) - Width 210 miles (340 km) - Length 340 miles (545 km) - % water 2. ...
Motto: Fortis et liber (Latin: Strong and free) Official languages English Flower Wild rose Capital Edmonton Largest city Calgary Lieutenant-Governor Norman Kwong Premier Ralph Klein (PC) Parliamentary representation - House seat - Senate seats 28 6 Area Total - Land - Water (% of total) Ranked 6th 661,848 km² 642,317 km² 19...
Motto: Multis E Gentibus Vires (Latin: From many peoples, strength) Official languages English Flower Western Red Lily Capital Regina Largest city Saskatoon Lieutenant-Governor Gordon Barnhart Premier Lorne Calvert (NDP) Parliamentary representation - House seat - Senate seats 14 6 Area Total - Land - Water (% of total) Ranked 7th 651,036 km² 591...
 High precipitation supercell High Precipitation Image File history File links HPsupercell. ...
Image File history File links HPsupercell. ...
The HP supercell has a much heavier precipitation core that actually can wrap all the way around the mesocyclone. These are especially dangerous storms, since the mesocyclone is wrapped with rain and can hide the tornado from view. These storms also cause flooding due to heavy rain, damaging downbursts and weak tornadoes, although they are also known to produce strong to violent tornadoes. They have a lower potential for damaging hail than Classic and LP supercells, although damaging hail is possible. It has been observed by some spotters that they tend to produce more cloud-to-ground and intracloud lightning than the other types. Also, unlike the LP and Classic types, severe events usually occur at the front (southeast) of the storm. The HP supercell is the most common type of supercell in the United States east of the Mississippi River and in the southern parts of the provinces of Ontario and Quebec in Canada. A downburst is a column of sinking air that is capable of producing damaging straight-line winds over 100 mph, similar to, but distinguishable from tornadoes. ...
The Mississippi River, derived from the old Ojibwe word misi-ziibi meaning great river (gichi-ziibi big river at its headwaters), is the second-longest river in the United States; the longest is the Missouri River, which flows into the Mississippi. ...
Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages English (French has some legal status but is not fully co-official) Flower White trillium Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation - House seat - Senate seats...
Motto: Je me souviens (French: I remember) Official languages French Flower White garden lily Capital Quebec City Largest city Montreal Lieutenant-Governor Lise Thibault Premier Jean Charest (PLQ) Parliamentary representation - House seat - Senate seats 75 24 Area Total - Land - Water (% of total) Ranked 2nd 1,542,056 km² 1,183...
Severe weather Supercells can produce: - Large hail
- Damaging winds
- Deadly Tornadoes
- Flooding
- Deadly Cloud-to-Ground Lightning
Severe events associated with a supercell almost always occur in the area of the updraft/downdraft interface. In North America, this is most often the rear flank (southwest side) of the precipitation area in LP and classic supercells, but sometimes the leading edge (southeast side) of HP supercells.
While tornadoes are perhaps the most dramatic of these severe events, all are dangerous. High winds caused by powerful outflow can reach 130 km/h (80 mph) and downbursts can cause tornado-like damage. Flooding is the leading cause of death associated with severe weather.[4] A downburst is a column of sinking air that is capable of producing damaging straight-line winds over 100 mph, similar to, but distinguishable from tornadoes. ...
Note that none of these severe events are exclusive to supercells, although these events are highly predictable once a supercell has formed.
Some reports also suggest that the 26/7/2005 deluge in Mumbai(Bombay), India was caused by a super cell when there was a cloud formation 15 km. high over the city. On this day 94.4cm.(37.16in.) of rain fell over the city, of which 70cm.(27.56in.) fell in just 4 hours.
References - Structure and Dynamics of Supercell Thunderstorms - NWS
- University of Illinois World Weather Project
- Weather Glossary for Storm Spotters - NWS
- Lemon, Leslie R. (1998): On the Mesocyclone "Dry Intrusion" and Tornadogenesis[5]
- Lemon, Leslie R., Charles A. Doswell III (1979): "Severe Thunderstorm Evolution and Mesocyclone Structure as Related to Tornadogenesis". Monthly Weather Review Vol. 107, No. 9, pp. 1184-1197.[6]
- Browning, K.A. and Ludlam, F.H. (1962): "Airflow In Convective Storms", Quarterly Journal of the Royal Meteorological Society 88, 117-135.[7] (PDF)
Image File history File links Commons-logo. ...
Wikimedia Commons logo by Reid Beels The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ...
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