blocking anticyclone

A blocking anticyclone, or blocking high, is a high-pressure weather system that interrupts the normal west-to-east circulation of winds in the mid-latitudes. These systems are typically larger than cyclones and can persist for a week or more, significantly altering weather patterns by blocking or diverting the eastward progress of atmospheric depressions.1

In the Northern Hemisphere, anticyclones feature clockwise circulation, while in the Southern Hemisphere, it's counterclockwise. While anticyclones are generally associated with dry, stable air and clear skies, blocking anticyclones can lead to prolonged periods of stagnant air, potentially causing pollution buildup. In winter, they can contribute to colder-than-average temperatures and fog formation.231