During a warm front passage, which phenomenon might you expect first if experiencing a weather change?

During a warm front passage, the initial phenomenon often observed is the presence of hazy skies. This occurs because as a warm front approaches, the warm, moist air overrides the cooler air near the surface. Prior to the actual arrival of the front, this rising warm air leads to the formation of cirrus or high-altitude clouds, which may give the sky a hazy appearance. This haziness results from the increased moisture content in the atmosphere and the formation of clouds that often precede the front's leading edge.

Following the initial observation of hazy skies, other weather changes occur, such as increased cloudiness, followed later by light to moderate precipitation as the warm air rises and cools. It's common for pilots and meteorologists to observe this sequence of events, where the initial signs of a warm front are not as dramatic as what follows, such as heavy precipitation or gusty winds. Therefore, recognizing hazy skies as a precursor to the significant weather changes that follow is essential in understanding warm front behavior.