Why won't the White House reveal to the governors of the states where they're sending the Syrian refugees?

Just because there is a law that says the governors can't refuse to take them, does same said law say how long they will be allowed to stay?

They probably don't have a plan yet.
I rather doubt that the agencies responsible are terribly enthusiastic about this idea. If the bureaucracy is working correctly (HA!), they are doing some cross-talk in order to figure out transportation, security, and talking to potential host sites.
I am not holding my breath...

SSgt Alex Robinson
Because they've seen the same lists we have of states who say they will not take refugees!