Unfortunately pretty bumpy one along the jet stream. Ok out of SJC, turning occasional light to moderate over much of the US, especially the eastern half of the US, with occasional moderate-severe possible. The ocean crossing looks a bit better after the first hour and a half, with a bit of a break around the mid point of the ocean crossing. Back to light to moderate for the remainder of the flight though.
Might be easier to think of it as light to moderate for most of it, with the chance of moderate-severe over the eastern US, and just past Newfoundland / around the mid point. It's actually a tough forecast because looks like different modelers generated the maps for each step. Possible moderate-severe indicated also by another map just west of LHR unfortunately.
Bummer forecast, hopefully you find some smoother air up there.