Nicholas Del Medico passed along this link to an article from the June 1999 issue of Naval History. It seems the Red Cross, which appears to have been joined at the hip to the White House at the time, had advance warning that there was going to be trouble in Hawaii and ramped up its activities there accordingly in the weeks just before December 7, 1941. Meanwhile, of course, the actual military commanders at Pearl Harbor were kept in the dark, the better to serve as scapegoats for FDR’s mendacity.