Semipermanent Highs and Lows

The Arctic is characterized by "semipermanent" patterns of high and low pressure. These patterns are semipermanent because they appear in charts of long-term average surface pressure. They can be considered to largely represent the statistical signature of where transitory high and low systems that appear on synoptic charts tend to be most common.

Aleutian Low

This semipermanent low pressure center is located near the Aleutian Islands. Most intense in winter, the Aleutian Low is characterized by many strong cyclones. Traveling cyclones formed in the subpolar latitudes in the North Pacific usually slow down and reach maximum intensity in the area of the Aleutian Low.

Icelandic Low

This low pressure center is located near Iceland, usually between Iceland and southern Greenland. Most intense during winter, in summer, it weakens and splits into two centers, one near Davis Strait and the other west of Iceland. Like its counterpart the Aleutian Low, it reflects the high frequency of cyclones and the tendency for these systems to be strong. In general, migratory lows slow down and intensify in the vicinity of the Icelandic Low.

Siberian High

The Siberian High is an intense, cold anticyclone that forms over eastern Siberia in winter. Prevailing from late November to early March, it is associated with frequent cold air outbreaks over east Asia.

Beaufort High

The Beaufort High is a high pressure center or ridge over the Beaufort Sea present mainly in winter.

North American High

The North American High is a relatively weak area of high pressure that covers most of North America during winter. This pressure system tends to be centered over the Yukon, but is not as well-defined as its continental counterpart, the Siberian High.