A lull is:
A lull is a term used to desribe the momentary decrease in the speed of the wind. You can contrast this with terms like, peak wind, or gust.
The Perihelion is:
The Perihelion is the point at which the sun is nearest to the earth. The date is January 3. The distance is around 91 million miles. The distance between the sun and earth is not related to earths seasons.
A disturbance is:
The term disturbance is used for many weather features. Most of the time it is used to desribe an item within the atmosphere, which creates unstable weather. A low-pressure system is one example of a disturbance.
A chinook is:
When winds move down the eastern slopes of the Rocky Mountains, they tend to warm. Some of these winds are called Chinook Winds (Snow Eater). The warm temperatures can rise 20-40 degrees within 15 minutes.
A trough is:
High and low pressure systems evolve and move around the globe. Through their evolution process they tend to take on many shapes. A "trough," in weather terms, is an elongated area of a low pressure.
