First guess is increased traffic in your area. I think that hop belongs to sprint, and they may just be getting loaded up at certain times. Considering your ping in that plot is under a tenth of a second, I wouldn't get too concerned, and would wait to see what happens after a few days (ie, does your ping stay up, or drop back to it's prior times, look for patterns in ping times and time of day you experience higher pings, etc). If you're still having issues in a few days, I'd probably post in the Help/Support forums.