Line echo wave pattern: Difference between revisions

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[[File:Line echo wave pattern.gif|thumb|left|Radar schematic of a LEWP. This shape is a single wave along the pattern, for real LEWPs this shape is [[tessellate]]d repeatedly in a linear fashion]]

[[File:Illinois-LEWP.jpg|thumb|right|A LEWP in Illinois/Indiana and Arkansas, associated with a [[April 19–24, 2011 tornado outbreak sequence|very large derecho]]]]

A '''line echo wave pattern''' ('''LEWP''') is a [[weather radar]] formation in which a single line of thunderstorms presenting multiple [[bow echo]]es forms south (or equatorward) of a [[Mesoscale meteorology|mesoscale]] [[low-pressure area]] with a rotating "head".<ref>{{cite book |last = Glickman |first = Todd S. (ed.) |authorlink=Todd Glickman |title = Glossary of Meteorology |publisher = American Meteorological Society |edition = 2nd |year = 2000 |___location = |pages = |url = http://glossary.ametsoc.org/wiki/Line_echo_wave_pattern |doi = |isbn = 978-1-878220-34-9 }}</ref> LEWP often are associated with a multiple-bow serial [[derecho]]<ref>{{cite web | url=http://www.crh.noaa.gov/iwx/?n=severestorms_2011apr19 Severe Storms of April 19th-20th | title=Severe Thunderstorms and Tornadoes of April 19-20, 2011 | publisher=National Weather Service Weather Forecast Office, Northern Indiana | date=April 24, 2011 | accessdate=July 28, 2012 | author=Obergfell; Lashley; Chamberlain}}</ref> and often produce tornadoes, some of which can be strong.<ref>{{cite web | url=http://www.wrh.noaa.gov/mtr/stormSummary/TorWx_3_18-23_2011/torwx_3_18-23.php | title=Waterspouts and Tornadoes March 2011 | publisher=National Weather Service Forecast Office (part of NOAA) | date=2011 | accessdate=July 28, 2012}}</ref> The existanceexistence of a LEWP on radar means that a serial [[derecho]] has developed or is likely to develop soon, much as a [[hook echo]] indicates the same for a [[tornado]].

A LEWP, according to the NWAS, is defined as "a [[squall line]] that has developed into a wave-like pattern due to acceleration at one end of the line and deceleration along the portion immediately adjacent."<ref>{{cite web | url=http://www.nwas.org/committees/avnwinterwx/doppler_weather_radar_overview.htm | title=Doppler Weather Radar Overview | publisher=NWAS | work=Echo Identification using NEXRAD: Line Echo Wave Pattern | accessdate=July 28, 2012}}</ref>