Temperate Cyclones

Published on 31 Jan 2025

Temperate cyclones are large-scale, low-pressure weather systems that form in middle latitudes due to the interaction of cold and warm air masses. Their movement, guided by westerly winds, brings diverse weather conditions, influencing regional climates and weather patterns in temperate zones.

Features of Temperate Cyclones

• Location: Extra-Tropical Cyclones are storm systems emerging in the mid and high latitudes, away from the tropics.

• Spread and height: They spread over 800-1200 km in diameter over 8-11 km height. 

• Energy source: They derive their energy from temperature differences between cold and warm air masses. 

• Frontal origin: The formation and intensification of temperate cyclones involve the presence of fronts—boundaries between different air masses. The collision of these air masses leads to the development of low-pressure systems.

• Movement: Temperate cyclones typically move from west to east due to the prevailing westerly winds in the middle latitudes.

• Influence of jet stream: Jet stream plays a major role in temperate cyclonogeneis and deciding the path of temperate cyclones. 

• Weather associated: The approach of a temperate cyclone is marked by fall in temperature, wind shifts and a halo around the sun and the moon, and a thin veil of cirrus clouds.

Conditions required for formation of temperate cyclones

The formation of temperate cyclones requires specific atmospheric conditions in the middle latitudes (between 30 and 60 degrees latitude) and can be explained using polar front theory. Key conditions include:

• Contrasting air masses: The collision of contrasting air masses, specifically cold polar air and warm tropical air, is crucial. This temperature difference initiates the cyclogenesis process.

• Fronts: The lifting of warm air over cold air along a front leads to the development and intensification of the cyclone.

• Coriolis effect: The Coriolis effect causes the cyclone's rotation. In the Northern Hemisphere, cyclones rotate counterclockwise, while in the Southern Hemisphere, they rotate clockwise.

• Jet streams: The presence of strong westerly winds in the upper atmosphere, known as jet streams, helps in steering and maintaining the structure of temperate cyclones.

• Upper-Level Divergence: Upper-level divergence of air helps in the vertical development of the cyclone, aiding its intensification

Tags:
Geography

Keywords:
Temperate Cyclones cold air masses warm air mass fronts Conditions required for formation of temperate cyclones

Syllabus:
General Studies Paper 1

Topics:
Physical Geography