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[[File:Illinois-LEWP.jpg|thumb|right|A LEWP in Illinois, associated with a very large derecho]]
A '''line echo wave pattern''' or ('''LEWP''') (pronouncedis a [[weather radar]] formation in which an area of thunderstorms forms a [[Mesoscale meteorology|mesoscale]] [[low-pressure area]] with a rotating "loophead" and, typically, a [[bow echo]] to its south (or spelledequatorward).<ref>{{cite outbook |last = Glickman |first = Todd S. (ed.) is|authorlink=Todd theGlickman radar|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 signatureare 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>
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>
A LEWP can be compared to the [[bow echo]], which usually indicates a powerful convective windstorm. Areas hit by the apices of bows often see the worst weather, with the highest winds and very heavy rain. However, if the sides of the bows reach enough of an orientation parallel to the derecho's movement, [[storm train|a very long-duration]] heavy rain event can result, leading to [[flash flood]]ing. A serial derecho can be in the form of a LEWP or a single, very large [[bow echo]].<ref>{{cite web | url=http://www.srh.noaa.gov/oun/?n=spotterglossary-figure4 | title=Line Echo Wave Pattern (LEWP) | publisher=National Weather Service Weather Forecast Office | work=Norman, OK: Figure 4, LEWP | date=December 2, 2009 | accessdate=July 28, 2012}}</ref>
== See also ==
LEWP events can produce strong, damaging winds and tornadoes.<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>
* [[Convective storm detection]]
* [[Mesoscale convective system]] and [[mesoscale convective complex]]
* [[Mesoscale convective vortex]]
* [[Rear-inflow jet]]
==References==
{{reflist|2}}
[[Category:Radar meteorology]]
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