Weather front

A weather front is a boundary separating two air masses whose characteristics differ, such as density, wind, temperature and humidity. Disturbed and unstable weather typically develops along these boundaries: cold fronts can bring thunderstorms and heavy precipitation, while warm fronts are usually preceded by gradual rainfall and fog. Even a front that produces little precipitation is generally marked by a noticeable shift in wind direction as it passes. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/