Just like the above, it looks just like it is rusting underneath the paint. Mine had about a one inch wide spot along the hem of the hood in the middle. It'* due to GM not using a proper primer to adhere to the Aluminum hood so it may pop loose in spots. I don't know what the correlation is though with it starting in the front, but based on other'* I've seen, the common spot for it to start is in the middle along the hem like mine and then travels up over to the top surface of the hood and across. It'* about $500 to get it repainted properly.
2003 Black SLE-Stock
2000 Mercury Mountaineer
1968 Oldsmobile Cutlass Convertible-455 cubic inches of muscle