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The Mid-October 2007 tornado outbreak was a widespread tornado outbreak that took place across much of the eastern half of North America starting on October 18, 2007 and continuing into the early hours of October 19. The outbreak was also responsible for five deaths; three in Michigan and two in Missouri, plus many injuries (including some from non-tornadic events). At least 64 tornadoes were confirmed including 16 on October 17 across six states including Texas, Oklahoma, Arkansas, Louisiana, Mississippi and Missouri with wind damage reported in Oklahoma, Kansas, Illinois, Iowa, Arkansas and Mississippi. On October 18, at least 48 tornadoes were confirmed across eight states including Florida, Alabama, Mississippi, Tennessee, Kentucky, Illinois, Indiana and Michigan, plus widespread straight line wind damage. Until 2010, this event held the record for largest tornado outbreak ever recorded in the month of October according to NOAA. ==Meteorological synopsis== A deep low pressure system (with a pressure of 977 mbar at its peak) moved across the Pacific Coast on October 15 and then crossed the Rockies during the following day and touched out some moist air from the Gulf of Mexico, major source for storm development and intensification. Not part of the main outbreak, 3 tornadoes were reported, during the overnight hours of October 16 towards October 17, across Randall County, Texas south of Amarillo on October 16 with 1 of them confirmed as a high EF1. That tornado caused damage to trees, fences, power poles, steel pipes, trailers and barns.〔(【引用サイトリンク】SPC Storm Reports for 10/16/07 )〕〔(【引用サイトリンク】Public Information Statement )〕 The next day a dry line, which separates the drier air from the more moist and humid air, formed ahead of the cold front across the Texas and Oklahoma Panhandles and tracked eastward. The high humidity levels with dew points in the 70s°F (low 20s°C), temperatures that in many areas were near 80 °F (27 °C), strong wind shear and the presence of the dry line helped developed the instability to produced severe thunderstorms across the Midwest and Southern Plains on October 17.〔 〕 A moderate risk for severe weather was issued by the Storm Prediction Center two days prior to the event. The storm then moved across the most of the Midwest on October 18, where a moderate risk was in effect also for two days for most of Illinois, Indiana and parts of Kentucky, although the moderate risk was revised further to the south and east to include western Ohio, western Tennessee, southeastern Missouri, northeastern Arkansas and a larger portion of Kentucky while Michigan and Wisconsin were no longer under a moderate risk. A slight risk of severe weather was forecast for a large area from beyond the Canadian border to the Florida Panhandle and Mobile Bay.〔 Dew points above 70 °F (21 °C) were reported well into the Ohio Valley, and dew points above 60 °F (16 °C) were reported as far north as northern Ontario.〔 The outbreak was expected to continue into October 19 east of the Appalachians, however, extensive cloud cover prevented any significant severe storms from developing although several wind reports were reported in Pennsylvania, New Jersey and Massachusetts. The storm then moved out into the Atlantic Ocean on October 20. 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「Mid-October 2007 tornado outbreak」の詳細全文を読む スポンサード リンク
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