 The descriptor "extratropical" signifies that this type of cyclone generally occurs outside the tropics and in the middle latitudes of Earth between 30° and 60° latitude.They are termed "mid-latitude cyclones" if they form within those latitudes, or post-tropical cyclones if a tropical cyclone has intruded into the mid latitudes.Weather forecasters and the general public often describe them simply as "depressions" or "lows".