My father was there. Had been there since mid-October. There was a Japanese sub spotted in the harbor a week before the attack.
My father said that every Friday and aircraft carrier and two battleships came into the harbor, and an aircraft carrier and two battleship went out of the harbor. Except on Friday, Dec 5, 1941 - then all the air craft carriers left Pearl Harbor.
Yeah, it wasn’t a surprise attack for everyone.
The US aircraft carriers were delivering aircraft to Wake Island and one other base. The Enterprise missed being caught at Pearl by a single day. Several of her returning aircraft were shot down by Pearl Harbor’s AAA because they arrived right after the Japanese 2nd wave attack.