What is a jet stream?

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Multiple Choice

What is a jet stream?

Jet streams are narrow bands of strong winds high in the atmosphere that steer weather systems. They form where there’s a big horizontal temperature difference between air masses, usually near the boundary between polar and mid-latitude air, close to the tropopause. These winds typically flow from west to east around mid- to high latitudes, at altitudes roughly 9–12 km (30,000–39,000 ft), with speeds often reaching well over 100 mph. Their position and strength matter for forecasting because the jet helps govern the movement of low-pressure systems and fronts. When a jet stream is strong or has a jet streak (a particularly intense core of winds), it increases divergence aloft, which can deepen surface lows and intensify storms. The other options don’t fit because calm winds near the equator, local mountain wind reversals, and clouds describe phenomena that aren’t jet streams.

Jet streams are narrow bands of strong winds high in the atmosphere that steer weather systems. They form where there’s a big horizontal temperature difference between air masses, usually near the boundary between polar and mid-latitude air, close to the tropopause. These winds typically flow from west to east around mid- to high latitudes, at altitudes roughly 9–12 km (30,000–39,000 ft), with speeds often reaching well over 100 mph.

Their position and strength matter for forecasting because the jet helps govern the movement of low-pressure systems and fronts. When a jet stream is strong or has a jet streak (a particularly intense core of winds), it increases divergence aloft, which can deepen surface lows and intensify storms. The other options don’t fit because calm winds near the equator, local mountain wind reversals, and clouds describe phenomena that aren’t jet streams.

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