I've also had this issue around 630 PDT / 930 EST as my fellow users have mentioned above. 2k+ ping spikes while not disconnecting from the game, no issues with any other devices/applications/etc.
I've done 20-30 hours of trouble shooting, researching, talking with ISP, and having my entire firmware/equipment replaced.
I've ran traceroutes, WINMTR ping files, and it all indicates that I get 100% packetloss after step 5 which means it's failing on Anet's server side (according to gw2support/network troubleshooting).
It's a shame that as a 10 year veteran of this game, I simply cannot play it. GW2 support just throws the 'reset your router' and 'flush your DNS' after asking for traceroutes that obviously show it's failing on Anet's side.