Extratropical cyclones, sometimes called mid-latitude cyclones or wave cyclones, are low pressure zones, which along with the anticyclones of high pressure zones, drive the weather over much of the Earth. Extratropical cyclones are capable of producing anything from cloudiness and mild showers to heavy gales and thunderstorms. These types of cyclones are defined as large scale (synoptic) low pressure weather systems that occur in the middle latitudes of the Earth. In contrast with tropical cyclones, they produce rapid changes in temperature and dew point along broad lines about the center of the cyclone called fronts.