Answer:high pressure system and cold fronts
Explanation:
High pressure develops in areas where air cools and sinks. This usually causes fair weather with cool temperatures and few clouds.
Cold fronts occur when warm air is pushed up into the atmosphere by colder air at the ground. These fronts tend to move faster than the other types of fronts and are associated with the most violent types of weather such as severe and super cell thunderstorms, although any type of front can produce these same storms. After a cold front passes it is common to have clear skies and a dramatic change in wind direction on top of the cooler air associated with the front itself.
