Weather Front Notes Weather Front: boundary that forms when air masses of different temperature, and moisture meet Warm Front: warm air mass overrides a cold air mass Warm less dense air rises above cold air,& gradually replaces cold air Weather: clouds, light rain or snow in winter can occur Cold Front: cold air mass pushes warm air mass Dense cold air slides under the lighter warm air pushing it upward Weather: dense clouds, thunderstorms, heavy rain or snow can occur Occluded Front: faster moving cold air mass overtakes slower moving warm air mass Weather: cool temperatures and large amounts of rain or snow Stationary Front: when two air masses move close to one another, but neither has enough force to move the other Weather: rain, snow, fog and clouds.