Instrument Rating Checkride Practice Test

What does it indicate when isobars are closely spaced on a weather map?

1. Calm weather with light winds

2. Strong pressure gradient with strong winds

3. Stable atmospheric conditions

4. Low visibility and steady precipitation

The correct answer is: Strong pressure gradient with strong winds

When isobars are closely spaced on a weather map, it indicates a strong pressure gradient. This means there is a significant difference in atmospheric pressure over a short distance, which typically results in strong winds. The closer the isobars are to each other, the steeper the pressure gradient becomes. Consequently, this leads to increased wind speeds as the atmosphere attempts to equalize the pressure differences. In contrast, widely spaced isobars would suggest a gentle pressure gradient with lighter winds, while stable atmospheric conditions would not be indicated by closely spaced isobars. Low visibility and steady precipitation can occur in various weather scenarios, but still, they are not directly linked to the spacing of isobars on a weather map. The relationship between isobar spacing and wind speed is fundamental to understanding weather conditions.