Polar front

In meteorology, the polar front is the weather front boundary between the polar cell and the Ferrel cell around the 60° latitude, near the polar regions, in both hemispheres. At this boundary a sharp gradient in temperature occurs between these two air masses, each at very different temperatures.^[1]

Atmospheric circulation diagram, showing the Hadley cell, the Ferrel cell, the Polar cell, and the various upwelling and subsidence zones between them

The polar front arises as a result of cold polar air meeting warm tropical air. It is a stationary front as the air masses are not moving against each other and stays stable.^[2] Off the coast of eastern North America, especially in winter, there is a sharp temperature gradient between the snow-covered land and the warm offshore currents.

The polar front theory says that mid-latitude extratropical cyclones form on boundaries between warm and cold air.^[3] In winter, the polar front shifts towards the Equator, whereas high pressure systems dominate more in the summer.

See also

• Polar vortex
• Horse latitudes
• Intertropical Convergence Zone