FAA Aircraft Dispatcher Practice Exam

What can be observed across a dry line?

1. Consistent temperature across the area

2. No change in weather patterns

3. Sharp changes in dew point temperature

4. Constant heavy rainfall

The correct answer is: Sharp changes in dew point temperature

A dry line is a boundary that separates moist air from dry air and is often associated with significant changes in weather conditions. When crossing a dry line, one can observe sharp changes in dew point temperature due to the differing moisture content of the air masses on either side. The air mass on one side of the dry line is typically characterized by higher humidity and a higher dew point, while the air mass on the other side is drier, with a much lower dew point. This stark contrast is what leads to the sharp changes in dew point temperature that can be monitored across the dry line. These shifts can often indicate the potential for severe weather as moist air lifts over the drier air, leading to the development of thunderstorms. The other options do not accurately describe the characteristics of a dry line. For example, you would not find consistent temperatures or no change in weather patterns due to the dynamic nature of these air masses. Similarly, constant heavy rainfall is not a typical feature across a dry line, which is more concerned with boundaries of moisture rather than precipitation.