Polar front

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Image:AtmosphCirc2.svg diagram, showing the Hadley cell, the Ferrel cell, the Polar cell, and the various upwelling and subsidence zones between them]]

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.{{Cite web |date=2022-02-07 |title=Polar Front: What Is It & The Definition |url=https://www.tomorrow.io/weather/blog/polar-front/ |access-date=2022-05-22 |website=Tomorrow.io Weather Blog |language=en}}

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.{{Cite web |title=What is a Polar Front? |url=https://www.kids-fun-science.com/polar-front.html |access-date=2022-05-22 |website=www.kids-fun-science.com}} 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.{{Cite web |date=2016-01-06 |title=Temperate Cyclones (Mid Latitude Cyclone or Extra tropical cyclones or Frontal Cyclones) |url=https://www.pmfias.com/temperate-cyclones-extra-tropical-cyclones-mid-latitude-cyclones-frontal-cyclones-geography-upsc-ias/ |access-date=2022-05-22 |website=PMF IAS |language=en-US}} In winter, the polar front shifts towards the Equator, whereas high pressure systems dominate more in the summer.