13 year old cat not eating his dry food anymore

My cat has always eaten dry food, and never had a problem with it. Suddenly he won't eat it anymore but is really showing he's hungry. He's always jumping on the countertop in the kitchen looking for food, meowing everytime we eat meals. It seems like he's starving but won't eat his own food. I'm confused, anyone have any ideas?

I would check out his mouth. He may have a tooth that is bothering him or a sore.

A cat not eating can be pretty serious.  I definitely recommend taking him to the vet today!  He may develop fatty liver disease if he goes without food for too long. 

Could be tooth problems or mouth ulcers.  Get some canned food to carry you over until you can get to the vet.