What characterizes the formation of a stationary front?

The formation of a stationary front is characterized by the meeting of cold and warm air masses where neither air mass is strong enough to displace the other. A stationary front typically occurs when opposing air masses converge, but the forces are balanced, causing the front to remain in place. This lack of movement can lead to prolonged periods of precipitation and cloudiness along the boundary.

In this scenario, the warm air is generally lighter and tends to rise over the denser, cooler air. Since neither air mass is advancing, weather conditions can stagnate, resulting in extended periods of similar weather without significant changes.

Other options either mischaracterize the behavior of the air masses or describe different phenomena. For instance, the idea of air masses moving in unison does not apply to a stationary front, as such fronts represent an equilibrium, not movement. Similarly, airflow past each other suggests a more dynamic interaction, which is not the case here since the fronts are stationary. Lastly, while air can be forced upward in other types of fronts (like warm or cold fronts), it does not happen consistently with stationary fronts, where the air masses remain in place.