What is an 'omega block'?

An omega block forms when a warm high‑pressure system becomes trapped between two cooler low‑pressure systems, creating a pattern like the Greek letter omega (Ω). Normally, the jet stream moves weather west to east, but in this setup it bends sharply north and south, stalling and isolating these systems. The current omega block over Europe pulls dry Saharan air northward, amplifying the heating effect of the block.