Editing Thunderstorm (section)

== Life cycle ==
[[File:Thunderstorm formation.jpg|thumb|upright=2.0|Stages of a thunderstorm's life]]
{{See also|Cloud}}

Warm air has a lower [[density]] than cool air, so warmer air rises upwards and cooler air will settle at the bottom<ref>{{cite book|url=https://archive.org/details/civilengineersp00fryegoog |title=Civil engineers' pocket book: a reference-book for engineers, contractors|author=Albert Irvin Frye|page=[https://archive.org/details/civilengineersp00fryegoog/page/n500 462]|publisher=D. Van Nostrand Company|date=1913|access-date=31 August 2009}}</ref> (this effect can be seen with a [[hot air balloon]]).<ref>{{cite book|url= https://books.google.com/books?id=ssO_19TRQ9AC&pg=PA112 |title=Ancient Chinese Inventions
| author =  Yikne Deng
| publisher = Chinese International Press
| isbn=978-7-5085-0837-5
| date=2005
| pages = 112–13|access-date=18 June 2009}}</ref> Clouds form as relatively warmer air, carrying moisture, rises within cooler air. The moist air rises, and, as it does so, it cools and some of the [[water vapor]] in that rising air [[condensation|condenses]].<ref>{{cite web|author=FMI|date=2007|url=http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/FgStr/backgr.htm |title=Fog And Stratus – Meteorological Physical Background|publisher=Zentralanstalt für Meteorologie und Geodynamik|access-date=7 February 2009}}</ref> When the moisture condenses, it releases energy known as [[latent heat]] of condensation, which allows the rising packet of air to cool less than the cooler surrounding air<ref>{{cite book|url=https://archive.org/details/stormworldhurric00moon |url-access=registration |title=Storm world: hurricanes, politics, and the battle over global warming|author=Chris C. Mooney|page=[https://archive.org/details/stormworldhurric00moon/page/20 20]|isbn=978-0-15-101287-9|publisher=Houghton Mifflin Harcourt|date=2007|access-date=31 August 2009}}</ref> continuing the cloud's ascension. If enough [[Convective available potential energy|instability]] is present in the atmosphere, this process will continue long enough for [[cumulonimbus]] clouds to form and produce [[lightning]] and [[thunder]]. Meteorological indices such as [[convective available potential energy]] (CAPE) and the [[lifted index]] can be used to assist in determining potential upward vertical development of clouds.<ref name="CAPE">{{cite journal|author=David O. Blanchard|title=Assessing the Vertical Distribution of Convective Available Potential Energy|journal=[[Weather and Forecasting]]|volume=13|issue=3|pages=870–7|publisher=[[American Meteorological Society]]|date=September 1998|doi= 10.1175/1520-0434(1998)013<0870:ATVDOC>2.0.CO;2|bibcode= 1998WtFor..13..870B|s2cid=124375544 |url=https://zenodo.org/record/1234637|doi-access=free}}</ref> Generally, thunderstorms require three conditions in order to form:
# Moisture
# An unstable airmass
# A lifting force (heat)

All thunderstorms, regardless of type, go through three stages: the '''developing stage''', the '''mature stage''', and the '''dissipation stage'''.<ref>{{cite web |title=Thunderstorm Basics |url=https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/#:~:text=The%20developing%20stage%20of%20a,this%20stage%20but%20occasional%20lightning. |website=NOAA National Severe Storms Laboratory |access-date=14 January 2021 |language=EN-US}}</ref><ref name="Extreme Weather">{{cite book|title=Extreme Weather|author=Michael H. Mogil|date=2007|publisher=Black Dog & Leventhal Publisher|location=New York|isbn=978-1-57912-743-5|pages=[https://archive.org/details/extremeweatherun0000mogi/page/210 210–211]|url=https://archive.org/details/extremeweatherun0000mogi/page/210}}</ref> The average thunderstorm has a {{convert|24|km|mi|abbr=on}} diameter. Depending on the conditions present in the atmosphere, each of these three stages take an average of 30 minutes.<ref name="tsbasics">{{cite web|url=http://www.nssl.noaa.gov/primer/tstorm/tst_basics.html|title=A Severe Weather Primer: Questions and Answers about Thunderstorms|author=National Severe Storms Laboratory|publisher=[[National Oceanic and Atmospheric Administration]]|date=15 October 2006|access-date=1 September 2009|archive-date=25 August 2009|archive-url=https://web.archive.org/web/20090825000832/http://www.nssl.noaa.gov/primer/tstorm/tst_basics.html|url-status=dead}}</ref>

=== Developing stage ===
[[File:Cumulus congestus to cumulonimbus incus.png|thumb|A [[cumulus congestus]]' transformation into a mature [[cumulonimbus incus]]]]

The first stage of a thunderstorm is the cumulus stage or developing stage. During this stage, masses of moisture are lifted upwards into the atmosphere. The trigger for this lift can be [[insolation|solar illumination]], where the heating of the ground produces [[thermals]], or where two winds converge forcing air upwards, or where winds blow over terrain of increasing elevation. The moisture carried upward cools into liquid drops of water due to lower temperatures at high altitude, which appear as ''[[Cumulus cloud|cumulus]]'' clouds. As the water vapor condenses into liquid, [[latent heat]] is released, which warms the air, causing it to become less dense than the surrounding, drier air. The air tends to rise in an ''[[updraft]]'' through the process of [[Atmospheric convection|convection]] (hence the term [[Precipitation (meteorology)|convective precipitation]]). This process creates a [[low pressure area|low-pressure zone]] within and beneath the forming thunderstorm. In a typical thunderstorm, approximately 500 million kilograms of water vapor are lifted into the [[Earth's atmosphere]].<ref name="condensationenergy">{{cite web|url=http://physics.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html |title=Rough Values of Various Processes |author=Gianfranco Vidali |date=2009 |access-date=31 August 2009 |publisher=[[Syracuse University]] |url-status=dead |archive-url=https://web.archive.org/web/20100315113421/http://physics.syr.edu/courses/modules/ENERGY/ENERGY_POLICY/tables.html |archive-date=15 March 2010 }}</ref>{{failed verification|date=April 2024|reason=The source is a list of power values, none of which pertain to thunderstorm moisture or energy.}}

=== Mature stage ===
[[File:Anvil shaped cumulus panorama edit crop.jpg|thumb|upright=1.2|Anvil-shaped thundercloud in the mature stage]]

In the mature stage of a thunderstorm, the warmed air continues to rise until it reaches an area of warmer air and can rise no farther. Often this 'cap' is the [[tropopause]]. The air is instead forced to spread out, giving the storm a characteristic [[anvil]] shape. The resulting cloud is called ''[[cumulonimbus incus]]''. The water droplets [[coalescence (meteorology)|coalesce]] into larger and heavier droplets and freeze to become ice particles. As these fall, they melt to become rain. If the updraft is strong enough, the droplets are held aloft long enough to become so large that they do not melt completely but fall as [[hail]]. While updrafts are still present, the falling rain drags the surrounding air with it, creating ''[[downdrafts]]'' as well. The simultaneous presence of both an updraft and a downdraft marks the mature stage of the storm and produces cumulonimbus clouds. During this stage, considerable internal [[turbulence]] can occur, which manifests as strong winds, severe lightning, and even [[tornado]]es.<ref>{{cite web|url=http://www.pilotsweb.com/wx/w_sense.htm|title=Structural Icing in VMC|author=Pilot's Web The Aviator's Journal|date=13 June 2009|access-date=2 September 2009|archive-date=19 August 2011|archive-url=https://web.archive.org/web/20110819055501/http://pilotsweb.com/wx/w_sense.htm|url-status=dead}}</ref>

Typically, if there is little [[wind shear]], the storm will rapidly enter the dissipating stage and 'rain itself out',<ref name="Extreme Weather" /> but, if there is sufficient change in wind speed or direction, the downdraft will be separated from the updraft, and the storm may become a [[supercell]], where the mature stage can sustain itself for several hours.<ref name="motion"/>
{{clear}}

=== Dissipating stage ===
[[File:Single-cell Thunderstorm in a No-shear Environment..jpg|thumb|upright=1.2|left|A thunderstorm in an environment with no winds to shear the storm or blow the anvil in any one direction]]
[[File:Flanking line on dissipating cumulonimbus incus cloud.jpg|thumb|[[Flanking line (meteorology)|Flanking line]] in front of a dissipating [[cumulonimbus incus]] cloud]]

In the dissipation stage, the thunderstorm is dominated by the downdraft. If atmospheric conditions do not support super cellular development, this stage occurs rather quickly, approximately 20–30 minutes into the life of the thunderstorm. The downdraft will push down out of the thunderstorm, hit the ground and spread out. This phenomenon is known as a [[downburst]]. The cool air carried to the ground by the downdraft cuts off the inflow of the thunderstorm, the updraft disappears and the thunderstorm will dissipate. Thunderstorms in an atmosphere with virtually no vertical wind shear weaken as soon as they send out an outflow boundary in all directions, which then quickly cuts off its [[inflow (meteorology)|inflow]] of relatively warm, moist air, and kills the thunderstorm's further growth.<ref>{{cite web|author=The Weather World 2010 Project|publisher=University of Illinois|url=http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/svr/comp/wind/home.rxml|title=Vertical Wind Shear|access-date=21 October 2006|date=3 September 2009}}</ref> The downdraft hitting the ground creates an [[outflow boundary]]. This can cause downbursts, a potential hazardous condition for aircraft to fly through, as a substantial change in wind speed and direction occurs, resulting in a decrease of airspeed and the subsequent reduction in lift for the aircraft. The stronger the [[outflow boundary]] is, the stronger the resultant vertical wind shear becomes.<ref>{{cite book|author=T. T. Fujita|date=1985|title=The Downburst, microburst and macroburst: SMRP Research Paper 210|author-link=Ted Fujita}}</ref>