寒冷前線 / cold front

寒冷前線は、冷たい空気が暖かい空気にぶつかり、その下へもぐり込むことでできる前線だ。冷たい空気は暖かい空気より重いため、暖かい空気を押し上げながら進んでいく。このため、前線付近では積乱雲ができやすく、急な強い雨や雷、突風を伴うことが多い。前線が通過した後は、気温が急激に下がり、北寄りの風に変わるのが特徴だ。

A cold front is a front that forms when a mass of cold air pushes its way under a mass of warm air. Since cold air is denser than warm air, it lifts the warm air as it advances. This often leads to the formation of cumulonimbus clouds along the front, bringing sudden, heavy rain, thunderstorms, and squalls. A notable characteristic after the front passes is a rapid drop in temperature and a shift in the wind direction to northerly.