Aside from the fac that this may be due in part to the tremendous volcanic outgassing as of late, yes, global warming.
As I understand from several programs and articles:
As the ice up north melts and dilutes the salt water it becomes less dense and stays near the surface instead of sinking as it is supposed to. This means that the driving force behind the Gulf Stream slows causing the Gulf Stream itself to slow. As a result the Gulf of Mexico and the gulf region becomes warmer (one of the reasons they're calling for a busier hurricane season). The other result is that the eastern seaboard stays cooler due to the loss of the gulf stream influence.