Daily Archives: October 28, 2024

Storm systems that form in middle or high latitudes, in regions of large temperature contrast are called extratropical cyclones. This contrasts with tropical cyclones, such as hurricanes, which form in regions or relatively uniform temperatures.

Extratropical cyclones are surface low-pressure systems where the air at the surface flows counterclockwise in the northern hemisphere and clockwise in the southern hemisphere. The winds around these centers of low-pressure spiral inward at the surface, forcing rising motions.  The rising air can result in clouds and precipitation. The process of extratropical cyclone development and intensification is referred to as cyclogenesis. In North America there are favorable regions for cyclogenesis, including the eastern slopes of mountain ranges, the Atlantic Ocean off the Carolina Coast, and the Gulf of Mexico. The jet stream also influences cyclogenesis. Continue reading →