That's a warm front. It creates low clouds and light precipitation.
Pressure differences between warm and cold air masses cause fronts or high/low pressure systems. A warm front is when a warm, moist air mass slides up and over a cold air mass, and a cold front is the opposite.
Cold air is denser than warm air, so it sinks below warm air due to gravity. As the cold air mass descends, it displaces the warm air mass, causing it to rise. This process creates a stable atmosphere where cold air remains near the surface and warm air stays aloft.
Warm air rises over cold air when a warm and cold front connect.
When warm air pushes into cold air the result is a warm front.
Warm air is lighter then cold air. So the cold air sinks and the warm air raise.
warm air goes over cold air.
Warm air moves over cold air and replaces it.
occlusion, where the cold air mass is forced aloft as the warm air rises over it, creating a mix of warm and cold air.
This is a warm front.
In a warm front, warm air replaces cold air as the warm air mass gradually advances over the cold air mass. This can lead to prolonged periods of steady precipitation, such as rain or drizzle, as the warm air is forced to rise over the cooler air. Cloudiness and milder temperatures are characteristic of warm fronts.
When warm air is lifted up over cold air, it is called "overrunning" or "warm air advection." This process leads to the warm air rising, cooling, and condensing to form clouds and precipitation as it interacts with the cold air at the surface.
When a cold front overtakes a warm front, it is known as an occluded front. This occurs when the cold air behind the cold front catches up with the warm air ahead of the warm front, forcing the warm air upward.