At SEA this morning and probably had too much time to kill in the A SC.
Just for kicks opened flight tracker and saw this inbound into SEA (from Calgary), this is probably breaking all speed records and verified from wikipedia... 648 mph for an E175 is just wow!
Looks like a detour but checked the radar as well.. nothing significant in the area.
Map View
Track Log
and E175 specs from Wikipedia -
Most likely pilots and passengers got a thrill ride courtesy Jet Stream