- Western Disturbance
Western Disturbance is the term used in
India ,Pakistan ,Afghanistan andNepal to describe anextratropical storm that brings sudden winter rain and snow to the northwestern parts of theIndian subcontinent . This is a non-monsoon al precipitation pattern driven by theWesterlies . The moisture in these storms usually originates over theMediterranean Sea and theAtlantic Ocean . Extratropical storms are a global, rather than a localized, phenomena with moisture usually carried in the upper atmosphere (unlike tropical storms where it is carried in the lower atmosphere). In the case of the subcontinent, moisture is sometimes shed as rain when the storm system encounters theHimalayas .Western Disturbances are important to the development of the
Rabi crop in the northern subcontinent, which includes the locally important staplewheat .References
* PBS Savage Planet feature on extratropical storms, http://www.pbs.org/wnet/savageplanet/02storms/01extratropical/indexmid.html
* Western disturbance news report, http://timesofindia.indiatimes.com/articleshow/1600979.cms
* USA Today article on extratropical storms, http://www.usatoday.com/weather/wstorm.htm
* "Westerlies to hit northwest back to back," http://www.blonnet.com/2007/03/08/stories/2007030801481200.htm
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