What do isobars on a synoptic weather map represent?

• A. Areas of equal rainfall
• B. Points of equal atmospheric pressure
• C. Lines of equal temperature
• D. Boundaries between warm and cold fronts

Answer: (B)

Isobars are lines that connect places with the same atmospheric pressure, usually at sea level. They show how pressure changes across a map. The spacing tells you how strong the pressure gradient is: closely packed isobars mean a steep gradient and stronger winds, while widely spaced isobars mean lighter winds. The pattern of isobars reveals high- and low-pressure centers, which helps explain wind direction and speed.

This is not a map of rainfall, which would relate to moisture and convection, and not a map of temperature, which would use isotherms. Boundaries between warm and cold air are fronts, not isobars, though fronts can influence pressure patterns.