FAA Aircraft Dispatcher Practice Exam

What happens during the lake effect phenomenon in winter?

1. Rain occurs on the leeward side

2. Fog consistently develops regardless of temperature

3. Snow bands may develop when cold air passes over warmer lake water

4. Temperatures rise significantly

The correct answer is: Snow bands may develop when cold air passes over warmer lake water

During the lake effect phenomenon, cold air moves over warmer lake water, leading to the development of localized weather patterns. Specifically, when the cold air flows over a relatively warm lake, it picks up moisture from the water's surface. As this moisture-laden air rises and cools, it condenses, forming clouds and precipitation. In winter, this process often results in heavy snowfall, particularly on the leeward side of the lake. The conditions are conducive to the formation of organized snow bands, which can lead to significant accumulations in short periods. This phenomenon is most pronounced in areas close to large lakes, where the temperature difference between the cold air and the warmer lake can be substantial enough to trigger this effect. Other phenomena described in the options do not accurately reflect the typical outcomes of the lake effect. Rain on the leeward side relates more to general weather patterns and not specifically to the lake effect in winter. Fog may occur in various weather conditions, but it is not a consistent outcome associated specifically with the lake effect. Finally, temperatures do not rise significantly due to this phenomenon; in fact, cold air moving over the lake typically leads to further cooling conditions.