What do the numbers on isobars indicate?
Official USCG Answer & Rule Citation
Correct Answer: Option B — barometric pressure
Isobars are lines of constant barometric pressure plotted on weather charts. The values associated with these lines represent the pressure at mean sea level, typically measured in millibars or hectopascals. Closely spaced isobars indicate a steep pressure gradient, which correlates to higher wind speeds and more intense weather systems.
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