Denyav twisted the electrons to say:
So, if we where to accept your premise that the White House knew not only
that the Japanese where coming but also the day they would be "arriving",
why not warn Pearl Harbour?
Good Question,but I think Kimmel gave a very clear answer to this question
during interview in 1958.

You "think", but you're not sufficiently sure to actually tell us what it
was he might have said?

After all, if you're planning on joining a
war it's generally considered an advantage not to lose large amounts of
men and equipment on day 1!
Amounts of men and equipment lost in Pearl Harbor is very insignificant in
comparison with manpower and production resources of US,as the later
developments in war proved.

How many fewer trained, and available for service, men did the USN have
through to say the beginning of February the next year? Saying that it
was insignificant next to the size of the USN in late 1944 is hardly
relevant as it would take the USN 3 years to get to that size ...

No need to sortie the fleet if you still want a "sneak attack", just get
them placed on alert - ie: all anti-aircraft guns manned and ready and a
decent CAP (with the rest of the fighters on +5/+15) overhead.
Pearl Harbors shortcomings were well known,in fact during pre-attack
meetings Kimmel always maintained that only viable defense would be
the keeping the fleet in open sea and his views shared by everybody.

Maybe, but if you're the government and for some reason you want a sneak
attack to occur then you'll make sure that such a viewpoint is ignored.
Afterall, Pearl Harbour is only 40 feet deep and has reasonably narrow
and twisted entrances which coupled with netting should deal with the
threat from torpedo bombers and/or submarines. High-level and/or dive
bombing can thwarted by a combination of a waiting CAP followed by
anti-aircraft fire.
--
These opinions might not even be mine ...
Let alone connected with my employer ...