Unusual Lag

I live on the U.S. East Coast and for the most part I've barely experienced lag issues with CrossFire. But for the past four days, I've had consistent and frequent surges of lag when I'm playing. I would have it reading as ~70 and then surge to 500-1000 all the time. I've reset my router, repaired my connection, speeded up my computer and everything but it hasn't made a difference.

I live in the U.S. and I have a good ISP so I don't see why this is happening, especially when things were going smoothly before. Any help is appreciated, thanks.