Recently, devastating floods in some countries were linked to Omega atmospheric blocking event.
Key points
- Omega blocking events have also been linked to other extreme weather events in the past, including the Pakistan floods in 2011, extreme rainfall in northwestern Iran in 2008 and the 2019 heatwaves during May in France and July in Germany.
- Such events are currently quite difficult to predict.
- Such an event occurs when a high pressure system gets trapped between one or two low pressure systems and persists for a long time, leading to extreme weather events such as storms, floods and heatwaves.
- Blocks are areas of high pressure that remain nearly stationary and distort the usual eastward progression of pressure systems.
- 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.
