Great Circle Route?

Question

Flying from Narita to Newark we flew across the Pacific and entered US airspace in Washington. Return flight to Hong Kong, we flew over the top and encountered a headwind >30 knots, most of the way. Why? Is this typical? I don't remember this much deviation in my day, have the jet streams changed that much?

Answer 1

Jet streams change daily which is why the North Atlantic Tracks (NATs) deviate. Also flying westbound you are usually encountering headwinds and tailwinds flying eastbound (in the northern hemisphere)

I know you flew the great circle route and not trans-atlantic, but just making the point that the winds change and aren't always at the same position.

You can view the jet stream's location if you click on the progression weather charts on the NOAA-aviation website.