Editing Thunderstorm (section)

===Multicell lines===
{{Main|Squall line}}
{{See also|List of derecho events}}

A squall line is an elongated line of [[thunderstorms#Severe thunderstorms|severe thunderstorms]] that can form along or ahead of a [[cold front]].<ref>{{cite web|url=http://amsglossary.allenpress.com/glossary/search?id=squall-line1|author=Glossary of Meteorology|title=Squall line|date=2009|access-date=14 June 2009|publisher=[[American Meteorological Society]]|url-status=dead|archive-url=https://web.archive.org/web/20081217175139/http://amsglossary.allenpress.com/glossary/search?id=squall-line1|archive-date=17 December 2008}}</ref><ref>{{cite web|url=http://amsglossary.allenpress.com/glossary/search?id=prefrontal-squall-line1|author=Glossary of Meteorology|title=Prefrontal squall line|date=2009|access-date=14 June 2009|publisher=[[American Meteorological Society]]|url-status=dead|archive-url=https://web.archive.org/web/20070817224959/http://amsglossary.allenpress.com/glossary/search?id=prefrontal-squall-line1|archive-date=17 August 2007}}</ref> In the early 20th century, the term was used as a synonym for [[cold front]].<ref name="OU">{{cite web|author=University of Oklahoma|date=2004|url=http://weather.ou.edu/~metr4424/Files/Norwegian_Cyclone_Model.pdf|title=The Norwegian Cyclone Model|access-date=17 May 2007 |archive-url = https://web.archive.org/web/20060901163934/http://weather.ou.edu/~metr4424/Files/Norwegian_Cyclone_Model.pdf |archive-date = 1 September 2006}}</ref> The squall line contains heavy [[precipitation (meteorology)|precipitation]], [[hail]], frequent [[lightning]], strong straight line winds, and possibly [[tornado]]es and [[waterspouts]].<ref>{{cite web|author=Office of the Federal Coordinator for Meteorology |date=2008 |url=http://www.ofcm.gov/slso/pdf/slsochp2.pdf |title=Chapter 2: Definitions |pages=2–1 |publisher=[[NOAA]] |access-date=3 May 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090506002006/http://www.ofcm.gov/slso/pdf/slsochp2.pdf |archive-date=6 May 2009 }}</ref> [[Severe weather]] in the form of strong straight-line winds can be expected in areas where the squall line itself is in the shape of a [[bow echo]], within the portion of the line that bows out the most.<ref>{{cite web|url=http://amsglossary.allenpress.com/glossary/search?p=1&query=bow+echo&submit=Search|author=Glossary of Meteorology|title=Bow echo|date=2009|access-date=14 June 2009|publisher=[[American Meteorological Society]]|url-status=dead|archive-url=https://web.archive.org/web/20110606103620/http://amsglossary.allenpress.com/glossary/search?p=1&query=bow+echo&submit=Search|archive-date=6 June 2011}}</ref> [[Tornado]]es can be found along waves within a [[line echo wave pattern]], or LEWP, where mesoscale [[low pressure area]]s are present.<ref>{{cite book|author=Glossary of Meteorology|date=2009|url=http://amsglossary.allenpress.com/glossary/search?id=line-echo-wave-pattern1|title=Line echo wave pattern|publisher=[[American Meteorological Society]]|isbn=978-1-878220-34-9|access-date=3 May 2009|url-status=dead|archive-url=https://web.archive.org/web/20080924175030/http://amsglossary.allenpress.com/glossary/search?id=line-echo-wave-pattern1|archive-date=24 September 2008}}</ref> Some bow echoes in the summer are called [[derecho]]s, and move quite fast through large sections of territory.<ref name="noaa">{{cite web| url=http://www.spc.noaa.gov/misc/AbtDerechos/derechofacts.htm| title=About Derechos| publisher=[[Storm Prediction Center]], NCEP, NWS, NOAA Web Site| author= Stephen F. Corfidi| author2= Jeffry S. Evans| author3= Robert H. Johns| name-list-style= amp | date=2015| access-date=17 February 2015}}</ref> On the back edge of the rain shield associated with mature squall lines, a [[wake low]] can form, which is a mesoscale low pressure area that forms behind the mesoscale high pressure system normally present under the rain canopy, which are sometimes associated with a [[heat burst]].<ref>{{cite book |author= Glossary of Meteorology |title= Heat burst |publisher= [[American Meteorological Society]] |date= 2009 |url= http://amsglossary.allenpress.com/glossary/search?id=heat-burst1 |isbn= 978-1-878220-34-9 |access-date= 14 June 2009 |url-status= dead |archive-url= https://web.archive.org/web/20110606102146/http://amsglossary.allenpress.com/glossary/search?id=heat-burst1 |archive-date= 6 June 2011 }}</ref> This kind of storm is also known as "Wind of the Stony Lake" ({{Lang-zh|s=石湖风|t=石湖風}}; shi2 hu2 feng1) in southern China.<ref>{{cite web | date = 17 June 2005 | url = http://www.hko.gov.hk/education/edu01met/wxphe/ele_squalle.htm | title = Squall lines and "Shi Hu Feng" – what you want to know about the violent squalls hitting Hong Kong on 9 May 2005 | publisher = Hong Kong Observatory | access-date = 23 August 2006 | archive-date = 25 October 2019 | archive-url = https://web.archive.org/web/20191025222307/http://www.hko.gov.hk/education/edu01met/wxphe/ele_squalle.htm | url-status = dead }}</ref>