Landspout

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A landspout tornado forms from a developing thunderstorm near Cheyenne Wells, Colorado. Landspouts are exceptionally common in Eastern Colorado.[1][2]
A landspout near North Platte, Nebraska on May 22, 2004. Note the characteristic smooth, tubular shape, similar to that of a fair-weather waterspout.
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Landspout is a term created by atmospheric scientist Howard B. Bluestein in 1985 for a kind of tornado not associated with a mesocyclone.[3] The Glossary of Meteorology defines a landspout as

"Colloquial expression describing tornadoes occurring with a parent cloud in its growth stage and with its vorticity originating in the boundary layer.
The parent cloud does not contain a preexisting mid-level mesocyclone. The landspout was so named because it looks like "a weak Florida Keys waterspout over land."[4]
Landspouts are typically (though not always) weaker than supercell tornadoes.

Characteristics[]

Landspouts are a type of tornado that forms during the growth stage of a cumulus congestus or cumulonimbus cloud stretching boundary layer vorticity upward and into the cloud's updraft. These generally are smaller and weaker than supercell tornadoes and do not form from a mesocyclone or pre-existing rotation in the cloud. Because of this, landspouts are rarely detected by Doppler weather radar.[5]

Landspouts share a strong resemblance and development process to that of waterspouts, usually taking the form of a translucent and highly laminar helical tube. "They are typically narrow, rope-like condensation funnels that form while the thunderstorm cloud is still growing and there is no rotating updraft", according to the National Weather Service.[2] Landspouts are considered tornadoes since a rapidly rotating column of air is in contact with both the surface and a cumuliform cloud. Not all landspouts are visible, and many are first sighted as debris swirling at the surface before eventually filling in with condensation and dust.

Life cycle[]

Forming in relation to and under updrafts, a landspout generally lasts for less than 15 minutes; however, they can persist substantially longer, and produce heavy damage. They progress through recognizable stages of formation, maturation and dissipation, and tend to decay when a downdraft or significant precipitation occur nearby. They may form in lines or groups of multiple landspouts.[6]

Damage[]

Landspouts are commonly weak; however, on rare occasions, a landspout can be as strong as an EF3 tornado.

See also[]

References[]

  1. ^ Judson Jones (21 May 2020). "Why Landspout Tornadoes are Common in Colorado". The Denver Post.
  2. ^ a b Judson Jones (8 June 2021). "The No. 1 US county for producing tornadoes just spawned another landspout". CNN.
  3. ^ Bluestein, Howard B. (1985). "The formation of a "landspout" in a "broken-line" squall line in Oklahoma". Preprints, 14th Conf. On Severe Local Storms, Indianapolis, American Meteorological Society. 14: 267–270. doi:10.1175/1520-0434(1999)014<0558:AHOSSI>2.0.CO;2. Retrieved 27 March 2007.
  4. ^ American Meteorological Society (2000). "Glossary of Meteorology, Second Edition". ametsoc.org. Archived from the original on 6 April 2007. Retrieved 27 March 2007.
  5. ^ Wakimoto; Wilson (1989). "Non-supercell Tornadoes". Monthly Weather Review. 117 (6): 1113–1140. Bibcode:1989MWRv..117.1113W. doi:10.1175/1520-0493(1989)117<1113:NST>2.0.CO;2.
  6. ^ Forbes; Wakimoto (1983). "A Concentrated Outbreak of Tornadoes, Downbursts and Microbursts, and Implications Regarding Vortex Classification". Monthly Weather Review. 111 (1): 220–235. Bibcode:1983MWRv..111..220F. doi:10.1175/1520-0493(1983)111<0220:ACOOTD>2.0.CO;2.

External links[]

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