Hardwood floor problem

I want to install ceramic tile in my hallway but ran into the following problem. I removed the carpeting and found out that in one area that the oak hardwood floor had buckeled to a height of about 3/8 of an inch. The floor appears to be solid but I need a solid subfloor for ceramic tile. I tried to screw it down with negative results. I was thinking that if I run a circular saw down the middle of the buckeled area a few times in order to give the wood more space it may go back down enough where I can screw it to the sub floor below. Anybody think this may work or any other ideas? I don't care what the floor will look like because it's ruined anyways as it's going to be either tile or carpeting again anyways. Thanks in advance.

Bernie

 

I use my saw and cut thru like ya said, it works for us all the time, be sure ya screw back into floor good.