What guides the tracks of large storms in the mid-latitudes?

• A. The jet stream
• B. Sea-surface temperature alone
• C. The Earth's inner core
• D. The ozone layer

Answer: (A)

Tracks of large storms in the mid-latitudes are guided by the jet stream, a fast-moving ribbon of upper-level winds that flows from west to east. This powerful stream acts like a steering current for weather systems, especially extratropical cyclones that form between cold polar air and warmer mid-latitude air. The jet stream’s position and its wavy ridges and troughs determine where storms travel; when it bends south, storms shift southward, and when it bulges north, they follow. Sea-surface temperature can influence how strong a storm becomes, but it doesn’t set its path. The Earth’s inner core and the ozone layer don’t steer mid-latitude storm tracks.