From AMS Glossary
- The low pressure center located near Iceland (mainly between Iceland and southern Greenland) on mean charts of sea level pressure.
It is a principal center of action in the atmospheric circulation of the Northern Hemisphere. It is most intense during winter, having a January central pressure below 996 mb. In summer, it not only weakens but also tends to split into two centers, one near Davis Strait and the other west of Iceland. Like its Pacific counterpart, the Aleutian low, its daily position and intensity vary greatly so that it is best regarded as a region where migratory lows tend to slow up and deepen.