Dry thunderstorm

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A cloud-to-ground lightning strike during a dry thunderstorm near Wagga Wagga, Australia Cloud to ground lightning strikes south-west of Wagga Wagga.jpg
A cloud-to-ground lightning strike during a dry thunderstorm near Wagga Wagga, Australia

A dry thunderstorm is a thunderstorm that produces thunder and lightning, but where all or most of its precipitation evaporates before reaching the ground. [1] Dry lightning refers to lightning strikes occurring in this situation. Both are so common in the American West that they are sometimes used interchangeably. [2]

Contents

Dry thunderstorms occur essentially in dry conditions, and their lightning is a major cause of wildfires. [3] [4] [5] Because of that, the United States National Weather Service, and other agencies around the world, issue forecasts for its likelihood over large areas. [4] [6]

Where dry thunderstorms occur

Dry thunderstorms generally occur in deserts or places where the lower layers of the atmosphere usually contain little water vapor. Any precipitation that falls from elevated thunderstorms can be entirely evaporated as it falls through the lower dry layers. They are common during the summer months across much of western North America and other arid areas. The shaft of precipitation that can be seen falling from a cloud without reaching the ground is called "virga". [7]

A thunderstorm does not have to be completely dry to be considered dry; in many areas 0.1 inches (2.5 mm) is the threshold between a "wet" and "dry" thunderstorm. [1]

Hazards

Dry thunderstorms are notable for two reasons: they are the most common natural origin of wildland fires, and they can produce strong gusty surface winds that can fan flames.[ citation needed ]

Dust storms

Strong winds often develop around dry thunderstorms as the evaporating precipitation causes excessive cooling of the air beneath the storm, which increases its density and thereby its weight relative to the surrounding air. This cool air then descends rapidly and fans out upon impacting the ground, an event often described as a dry microburst. As the gusty winds expand outward from the storm, dry soil and sand are often picked up by the strong winds, creating dust and sand storms known as haboobs. [8]

Fires

A lightning-sparked wildfire in Nevada. 2011-08-04 20 00 00 Susie Fire in the Adobe Range west of Elko Nevada.jpg
A lightning-sparked wildfire in Nevada.

In areas where trees or other vegetation are present, there is little to no rain that can prevent the lightning from causing them to catch fire. Storm winds also fan the fire and firestorm, causing it to spread more quickly. [9]

Pyrocumulonimbus are cumuliform clouds that can form over a large fire and that are particularly dry. [10] When the higher levels of the atmosphere are cooler, and the surface is thus warmed to extreme temperatures due to a wildfire, volcano, or other event, convection will occur, and produce clouds and lightning. They are similar to any cumulus cloud but ingest extra particulates from the fire. This increases the voltage difference between the base and the top of the cloud, helping to produce lightning.[ citation needed ]

Climate change

Climate change is expected to alter patterns of lightning-ignited wildfires. A key factor in the ignition of these wildfires is the type of lightning, with long-continuing-current (LCC) lightning being particularly significant. The risk of lightning-ignited wildfires is influenced not only by the occurrence of LCC lightning but also by the availability of dry fuel, which is influenced by how much rain has fallen before. Scientists predict, some places will see more LCC lightning and less rain, making it easier for wildfires to start. Areas like Southeastern Asia, South America, Africa, and Australia, along with parts of North America and Europe, could be at higher risk for these lightning-caused wildfires. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Cumulonimbus cloud</span> Genus of dense, towering vertical clouds

Cumulonimbus is a dense, towering, vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. Above the lower portions of the cumulonimbus the water vapor becomes ice crystals, such as snow and graupel, the interaction of which can lead to hail and to lightning formation, respectively.

<span class="mw-page-title-main">Thunderstorm</span> Storm characterized by lightning and thunder

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 storm is any disturbed state of the natural environment or the atmosphere of an astronomical body. It may be marked by significant disruptions to normal conditions such as strong wind, tornadoes, hail, thunder and lightning, heavy precipitation, heavy freezing rain, strong winds, wind transporting some substance through the atmosphere such as in a dust storm, among other forms of severe weather.

<span class="mw-page-title-main">Squall line</span> Line of thunderstorms along or ahead of a cold front

A squall line, or more accurately a quasi-linear convective system (QLCS), is a line of thunderstorms, often forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front. Linear thunderstorm structures often contain heavy precipitation, hail, frequent lightning, strong straight-line winds, and occasionally tornadoes or waterspouts. Particularly strong straight-line winds can occur where the linear structure forms into the shape of a bow echo. Tornadoes can occur along waves within a line echo wave pattern (LEWP), where mesoscale low-pressure areas are present. Some bow echoes can grow to become derechos as they move swiftly across a large area. On the back edge of the rainband associated with mature squall lines, a wake low can be present, on very rare occasions associated with a heat burst.

<span class="mw-page-title-main">Haboob</span> Type of intense dust storm

A haboob is a type of intense dust storm carried by the wind of a weather front. Haboobs occur regularly in dry land area regions throughout the world.

<span class="mw-page-title-main">Outflow boundary</span> Mesoscale boundary separating outflow from the surrounding air

An outflow boundary, also known as a gust front, is a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump. Outflow boundaries can persist for 24 hours or more after the thunderstorms that generated them dissipate, and can travel hundreds of kilometers from their area of origin. New thunderstorms often develop along outflow boundaries, especially near the point of intersection with another boundary. Outflow boundaries can be seen either as fine lines on weather radar imagery or else as arcs of low clouds on weather satellite imagery. From the ground, outflow boundaries can be co-located with the appearance of roll clouds and shelf clouds.

This is a list of meteorology topics. The terms relate to meteorology, the interdisciplinary scientific study of the atmosphere that focuses on weather processes and forecasting.

In meteorology, a heat burst is a rare atmospheric phenomenon characterized by a sudden, localized increase in air temperature near the Earth's surface. Heat bursts typically occur during night-time and are associated with decaying thunderstorms. They are also characterized by extremely dry air and are sometimes associated with very strong, even damaging, winds.

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<span class="mw-page-title-main">Cumulus congestus cloud</span> Form of cumulus clouds

Cumulus congestus or towering cumulus clouds are a species of cumulus that can be based in the low- to middle-height ranges. They achieve considerable vertical development in areas of deep, moist convection. They are an intermediate stage between cumulus mediocris and cumulonimbus, sometimes producing rainshowers, snow, or ice pellets. Precipitation that evaporates before reaching the surface is virga.

<span class="mw-page-title-main">Fire whirl</span> Whirlwind induced by and often composed of fire

A fire whirl or fire devil is a whirlwind induced by a fire and often composed of flame or ash. These start with a whirl of wind, often made visible by smoke, and may occur when intense rising heat and turbulent wind conditions combine to form whirling eddies of air. These eddies can contract to a tornado-like vortex that sucks in debris and combustible gases.

<span class="mw-page-title-main">Cumulonimbus flammagenitus</span> Thunderstorm cloud that forms above a heat source

The cumulonimbus flammagenitus cloud (CbFg), also known as the pyrocumulonimbus cloud, is a type of cumulonimbus cloud that forms above a source of heat, such as a wildfire, nuclear explosion, or volcanic eruption, and may sometimes even extinguish the fire that formed it. It is the most extreme manifestation of a flammagenitus cloud. According to the American Meteorological Society’s Glossary of Meteorology, a flammagenitus is "a cumulus cloud formed by a rising thermal from a fire, or enhanced by buoyant plume emissions from an industrial combustion process."

<span class="mw-page-title-main">Air-mass thunderstorm</span> Thunderstorm that is generally weak and usually not severe

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References

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  3. Hessilt, Thomas D.; Abatzoglou, J. T.; Chen, Y.; Randerson, J. T.; Scholten, R. C.; van der Werf, Guido; Veraverbeke, S. (April 19, 2022). "Future increases in lightning ignition efficiency and wildfire occurrence expected from drier fuels in boreal forest ecosystems of western North America". Environmental Research Letters. 17 (5): 054008. Bibcode:2022ERL....17e4008H. doi: 10.1088/1748-9326/ac6311 . S2CID   247869214.
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  7. Ferguson, Sue A.; Steven, J. McKay; Miriam, L. Rorig; Werth, Paul (May 2007). "Model-Generated Predictions of Dry Thunderstorm Potential". Journal of Applied Meteorology and Climatology. 46 (5): 605–614. Bibcode:2007JApMC..46..605R. doi: 10.1175/JAM2482.1 .
  8. Idso, S. B.; Ingram, R. S.; Pritchard, J. M. (1972). "An American Haboob". Bulletin of the American Meteorological Society. 53 (10): 930–935. Bibcode:1972BAMS...53..930I. doi: 10.1175/1520-0477(1972)053<0930:AAH>2.0.CO;2 .
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  10. "Pyrocumulonimbus". AMS Glossary. Retrieved December 31, 2019.
  11. Pérez-Invernón, Francisco J.; Gordillo-Vázquez, Francisco J.; Huntrieser, Heidi; Jöckel, Patrick (2023-02-10). "Variation of lightning-ignited wildfire patterns under climate change". Nature Communications. 14 (1): 739. Bibcode:2023NatCo..14..739P. doi:10.1038/s41467-023-36500-5. ISSN   2041-1723. PMC   9918523 . PMID   36765048.