Stage 1 - Turning Yellow

Stage 2 - Dying

Stage 3 - DEAD

What did you fertilize with and what herbicide was in it.

I fertilized with Scotts Weed & Feed. It says on the bag that it is for centipede. I'm wondering if that may be the issue though, the problem seems to stop right on my property line, the neighbor's yard doesn't show the same symptoms.

Is the area shaded by anything (buildings, trees, shrubs)?

If you still have the bag, can you tell us what the herbicide was? Specifically.

Does the bag have different application rates for bermuda, St Augustine, and/or centipede? Did you follow the guide for centipede? For centipede that one bag might be a lifetime supply. It doesn't need much fertilizer.

Active Ingredients

1.166% Atrazine
.024% Related Compounds

Here's the link to the website:
http://www.scotts.com/smg/goprod/lawn-pro-super-bonus-s-weed-and-feed/prod90008/

Is the area shaded by anything (buildings, trees, shrubs)?

No there is no shade

bnesmith,
It's a fungus. Same thing happening to my lawn.
Go buy a fungicide and read instructions.
Water only in the early morning hours, never at night.
Your mowing too high, centipede should be 1 1/2 inches tall in June, July and August, shorter to an inch in the fall.

Looks like Yellow Patch to me, google it. Centipede is a finicky grass, especially when grown outside of its natural enviroment.