Prevailing westerlies

Definition

Prevailing westerlies are the dominant winds that blow from the west to the east in the mid-latitudes of the Earth, typically between 30 and 60 degrees latitude in both hemispheres. These winds play a significant role in the general circulation of the atmosphere, influencing weather patterns, ocean currents, and climate conditions across vast regions.

5 Must Know Facts For Your Next Test

1. Prevailing westerlies are most pronounced in the mid-latitudes and can lead to storm tracks that affect the weather in both North America and Europe.
2. These winds are driven by the Coriolis effect, which results from the Earth's rotation, causing moving air to turn toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere.
3. The interaction of prevailing westerlies with other atmospheric circulation patterns can lead to the development of frontal systems, which are crucial for understanding storm formation.
4. Prevailing westerlies can also impact ocean currents, as they drive surface water movement in oceans like the Atlantic and Pacific, influencing global climate patterns.
5. Seasonal variations in prevailing westerlies can lead to changes in weather conditions, such as increased precipitation or prolonged dry spells, depending on their strength and position.

Review Questions

• How do prevailing westerlies influence weather patterns in mid-latitude regions?
  • Prevailing westerlies play a critical role in shaping weather patterns in mid-latitude regions by driving storm systems and influencing precipitation. As these winds move from west to east, they carry moisture-laden air, which can result in cloud formation and precipitation when it encounters landmasses. The interaction between these winds and local geographic features can create varied weather conditions, such as rainstorms or clear skies.
• Evaluate how prevailing westerlies interact with other atmospheric circulations like trade winds and jet streams.
  • Prevailing westerlies interact with trade winds and jet streams to create complex atmospheric dynamics. For instance, trade winds blow east to west near the equator, while prevailing westerlies move west to east at higher latitudes. This interaction leads to areas of convergence and divergence that can result in storm formation. Additionally, jet streams can amplify or modify prevailing westerly flows, influencing weather events such as cyclones or anticyclones.
• Synthesize information on how changes in prevailing westerlies could impact global climate patterns over time.
  • Changes in prevailing westerlies can significantly impact global climate patterns by altering precipitation distribution and temperature regimes across various regions. For example, a shift in the position or strength of these winds could lead to prolonged droughts or increased rainfall in specific areas. Such changes could have far-reaching consequences for ecosystems, agriculture, and human populations worldwide, illustrating how interconnected our climate system is and highlighting the importance of monitoring these wind patterns as part of climate change studies.

Related terms

Trade Winds: Trade winds are steady winds that flow from east to west in the tropics, between the equator and approximately 30 degrees latitude, playing a key role in tropical weather systems.

Jet Stream: Jet streams are fast-flowing air currents located in the upper levels of the atmosphere, which can significantly influence weather patterns and are often associated with the prevailing westerlies.

Hadley Cell: A Hadley cell is a tropical atmospheric circulation pattern that creates trade winds and influences weather systems, extending from the equator to about 30 degrees latitude.