Originally Posted by
USDHS1984
OK, so doing the math..........
We were doing a ground speed of 763MPH
We were at FL33 (lower than usual for this flight too)
Mach 1.0 at FL33 is ~670MPH (depending on temperature)
777-300ER's cruise at .84 Mach
So airspeed 'probably would have been' ~563mph (670x.84)
Thus tailwind must have been ~200MPH (763-563)

Pretty cool, eh? The time honored lament though is that the strong winds are always on your nose. Nice to have the converse for once.
I bet there was some good turbulence as the edges of the jet core were penetrated.