Figure 4.17

Rossby waves. Rossby waves are curves in the geostrophic winds. The polar and subtropical jet streams follow the curves in the Rossby waves. A trough occurs where Rossby waves bend equatorward, and a ridge forms where Rossby waves bend poleward. Rossby wave ridges often cause above-average temperatures on the ground and generally bring fair weather. Rossby wave troughs bring below-average temperatures and potentially stormy weather.