Supercell

Supercells can occur anywhere in the world under the right pre-existing weather conditions, but they are most common in the Great Plains of the United States in an area known as Tornado Alley.

A high number of supercells are seen in many parts of Europe as well as in the Tornado Corridor (es) of Argentina, Uruguay and southern Brazil and Paraguay.

Moisture streams in from the side of the precipitation-free base and merges into a line of warm uplift region where the tower of the thundercloud is tipped by high-altitude shear winds.

The cap puts an inverted (warm-above-cold) layer above a normal (cold-above-warm) boundary layer, and by preventing warm surface air from rising, allows one or both of the following: As the cooler but drier air circulates into the warm, moisture laden inflow, the cloud base will frequently form a wall, and the cloud base often experiences a lowering, which, in extreme cases, are where tornadoes are formed.

In North America, supercells usually show up on Doppler weather radar as starting at a point or hook shape on the southwestern side, fanning out to the northeast.

The rear flank downdraft, or RFD, carries precipitation counterclockwise around the north and northwest side of the updraft base, producing a "hook echo" that indicates the presence of a mesocyclone.

An anvil forms when the storm's updraft collides with the upper levels of the lowest layer of the atmosphere, or the tropopause, and has nowhere else to go due to the laws of fluid dynamics- specifically pressure, humidity, and density, in simple terms, the packet of air has lost its buoyancy and cannot rise higher.

RFDs are caused by mid-level steering winds of a supercell colliding with the updraft tower and moving around it in all directions; specifically, the flow that is redirected downward is referred to as the RFD.

Due to the lack of a heavy precipitation core, LP supercells often exhibit relatively weak radar reflectivity without clear evidence of a hook echo, when in fact they are producing a tornado at the time.

During spring and early summer, areas in which LP supercells are readily spotted include southwestern Oklahoma and northwestern Texas, among other parts of the western Great Plains.

Whereas classic, HP, and LP refer to different precipitation regimes and mesoscale frontal structures, another variation was identified in the early 1990s by Jon Davies.

Some reports suggest that the deluge on 26 July 2005 in Mumbai, India was caused by a supercell when there was a cloud formation 15 kilometres (9.3 mi) high over the city.

[20][failed verification] Supercells occur commonly from March to May in Bangladesh, West Bengal, and the bordering northeastern Indian states including Tripura.

The classic type Supercell formed over the Blue Mountains, mid-morning hitting the lower CBD and eastern suburbs by mid-afternoon with the hail similar in size to a cricket ball.

The ice was so heavy that a newly built shopping center's roof collapsed, birds were killed in the hail produced from the supercell, and people were stranded.

The following day many homes in Canberra were subjected to flash flooding, caused either by the city's infrastructure's inability to cope with storm water or through mud slides from cleared land.

In just 18 minutes, 19 mm (0.75 in) of rain fell, causing havoc as streets were flooded and trains, planes, and cars were brought to a standstill.

[citation needed] The region, which covers portions of Argentina, Uruguay, Paraguay, and Brazil during the spring and summer, often experiences strong thunderstorms which may include tornadoes.

One of the first known South American supercell thunderstorms to include tornadoes occurred on September 16, 1816, and destroyed the town of Rojas (240 kilometres (150 mi) west of the city of Buenos Aires).

On 21 April 1970, the town of Fray Marcos in the Department of Florida, Uruguay experienced an F4 tornado that killed 11, the strongest in the history of the nation.

The December 26, 2003, Tornado F3 happened in Cordoba, with winds exceeding 300 km/h, which hit Córdoba Capital, just 6 km from the city center, in the area known as CPC Route 20, especially neighborhoods of San Roque and Villa Fabric, killing 5 people and injuring hundreds.

[citation needed] In November 2009, four tornadoes, rated F1 and F2 reached the town of Posadas (capital of the province of Misiones, Argentina), generating serious damage in the city.

On February 21, 2014, in Berazategui (province of Buenos Aires), a tornado of intensity F1 caused material damage including a car was, with two occupants inside, which was elevated a few feet off the ground and flipped over asphalt, both the driver and his passenger were slightly injured.

In many towns of La Pampa, San Luis, Buenos Aires and Cordoba, intense hail stones fell up to 6 cm in diameter.

The most affected province was Córdoba, storms and supercells type "bow echos" also developed in Santa Fe and San Luis.

It spawned an F4 tornado in the Val de Sambre area, about 90 kilometers east of Lille, which impacted nearby cities such as Maubeuge and Hautmont.

It was described by Belgian meteorologist Frank Deboosere as "one of the worst storms in recent years" and caused much damage in Belgium – mainly in the provinces of East Flanders (around Ghent), Flemish Brabant (around Brussels) and Antwerp.

On July 28, 2013, an exceptionally long-lived supercell tracked along an almost 400 km long path across parts of Baden-Württemberg and Bavaria in southern Germany, before falling apart in Czechia.

On 6 May 2009, a well-defined hook echo was noticed on local South African radars, along with satellite imagery this supported the presence of a strong supercell storm.

The first, classified as an EF2 hit Meqheleng, the informal settlement outside Ficksburg, Free State which devastated shacks and homes, uprooted trees, and killed one small child.

A low precipitation supercell in rural Northeast Colorado .
Schematic of a supercell's components
Wind shear (red) sets air spinning (green).
The updraft (blue) 'bends' the spinning air upwards.
The updraft starts rotating with the spinning column of air.
Structure of a supercell. Northwestward view in the Northern Hemisphere
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
Radar reflectivity map
Schematics of an LP supercell
A low precipitation supercell near Greeley, Colorado
Schematics of an HP supercell
Satellite view of a supercell
Photo of the 1947 Sydney Hailstorm showing the hail hitting the water at Rose bay
Supercell In Kansas
Supercell In Kansas