When a warm air mass meets a cold air mass, it typically leads to the formation of a front, specifically a warm front or a cold front, depending on how the two air masses interact.
In the case of a warm front, the warm air rises over the cold air, often resulting in gradual cloud formation and precipitation that can last for an extended period, usually bringing light to moderate rain.
In the case of a cold front, the cold air pushes under the warm air, which can cause the warm air to rise rapidly, leading to the formation of cumulonimbus clouds and often resulting in more severe weather, such as thunderstorms and heavy rain showers.
Overall, the interaction of these air masses typically leads to changing weather conditions, including precipitation, temperature changes, and shifts in wind.