Per philo:
Bottom line is that the US knew the Japanese were going to attack.

When I was stationed at Hickam AFB, working the 4-midnight shift I used
to hitchhike into Waikiki every morning during the summer surf season.

One ride I got was from an old guy who claimed to have been manning the
radar installation near Wheeler AFB.

He claimed to have seen the attack coming on the radar, but higher-ups
blew him off both because radar was some sort of new-fangled thing that
nobody really understood and because they expected a flight of some sort
of US planes about that time.
--
Pete Cresswell