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This article describes severe weather terminology used by the Meteorological Service of Canada a department of Environment Canada. The article primarily describes various weather warnings, and their criteria. Related weather scales and general weather terms are also addressed in this article. Some terms may be specific to certain regions. ==Warning categories== Severe weather bulletins are issued as a watch or a warning, depending on the risk or severity of the event. Less severe events that could be a cause for concern will be issued as a special weather statement or Advisory. *Watches are issued when conditions are favourable for the development of severe weather. Watches are typically issued for local-scale events in which the timing and location of occurrence remains uncertain; such as severe thunderstorms or tornadoes. A watch is normally issued several hours in advance. A watch issued for severe summer storms is typically issued up to six hours in advance, whereas watches for winter events at least 12 to 24 hours in advance. Weather watches are issued for regular forecast regions affected. *Warnings are issued when severe weather is either imminent or occurring. Warnings for large scale events such as snowstorms are issued with an ideal lead time of at least six, and up to 24 hours. Severe thunderstorm warnings, by their nature, will be issued less than one hour in advance. Weather warnings are usually issued for regular forecast regions affected. Severe thunderstorm and tornado warnings however, may be issued specifically for smaller warning or "sub-regions" within the regular forecast area where available. Specific warning criteria varies by region, depending on geography, or other conditions in which a specific region may be vulnerable. *Special Weather Statements or Advisories are issued in a freestyle format for weather events that are unusual, cause general inconvenience or public concern and cannot adequately be described in a public weather forecast. They may reflect a warning in effect near the United States border. A Special Weather Statement may also be issued to indicate any potentially hazardous situation in the long term forecast. Updated statements, watches and warnings are re-issued or upgraded if required. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Severe weather terminology (Canada)」の詳細全文を読む スポンサード リンク
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