Omega Block developing over eastern North Atlantic

Omega  block on  500 mb forecast chart

NOAA OPC 48 hour 500 mb forecast chart

The current North Atlantic upper-air pattern is developing  an Omega block over the northeastern North Atlantic. This pattern gets its name because this upper air pattern looks like the Greek letter omega (Ω). Omega blocks tend to have two cut-off lows with one blocking high sandwiched between them. They also tend to be large in size, producing a persistent surface pattern.

Often the cut-off upper lows tend to dig southeastward into the lower-left portion of the omega which can, in turn, force the omega pattern to extend farther northward.  This disrupts the normal southwest to northeast storm  tracks which can allow options for minimum distance great-circle weather routes during winter from North Europe ports to US East Coast Ports.

Learn more about using the 500mb chart for weather routing.

NOAA OPC 48 hour surface forecast showing blocking high pressure

NOAA OPC 48 hour surface forecast.


About Fred Pickhardt

I am a marine meteorologist and sailed briefly with American Export Lines in the Far East trade after graduating from State University of New York Maritime College. I have extensive experience in weather analysis, weather forecasting, optimum ship routing, vessel performance evaluations and forensic weather event reconstructions. I founded Ocean Weather Services and as Owner and Chief Consultant currently provide optimum ship routing services and forensic marine weather reports to the maritime industry.
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2 Responses to Omega Block developing over eastern North Atlantic

  1. That high pressure system should be around where we are in the Azores. The result of this weather pattern is that we are experiencing English-type weather – albeit without the cold – in Terceira. The low pressure systems, which would normally track north of us are now to the south, bringing heavy rain and easterly winds. Hey ho!

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