Description

Omega blocks are a type of upper-level weather pattern. They are so-named because the isobars or geopotential height contours with which they are associated in the Northern Hemisphere resemble an Ω, the uppercase Greek letter omega. They typically have a low-high-low pattern, arranged in the west–east direction. The lows are referred to as "closed" or "cut-off" lows which are on either side of the omega high.