Much discussion on Fox News right now (1908 here in Phoenix, AZ).
It seems the US knew where the CBW strikes were launched from, and has checked no Russian aircraft were on site. Overnight attack to minimise impact of personnel at their workplace. No suggestion Putin was advised beforehand, but then monitoriting would have given them enough clues it was coming. USN destroyers had been training for 2 days before the launch.
Interesting timing for President Xi at Mar-del-Lago, who might see President Trump in a different light now.