Maybe intelligence pointing to a large transfer of Al Quds forces from Iran to Syria to prop up Assad has been discovered to be in the works?
Israel could not tolerate that and a war between Syria and Israel could break out bringing Syrian chem-bio weapons into play (not to mention likely Saddam weapons inventory).
The US would definitely have to get US citizens out then and there are lots of dual US-Israeli citizens.
Note the Der Speigel story indicating that Turkey is “expected” to imminently request Patriot missile batteries to be transferred from NATO inventory to its border with Syria and that German troops may be required to man them.
Things look to be getting hotter during the “end game” for the Assad Regime in Syria!
I wouldn't put it past Obama to have had the Benghazi operation ship some of Qaddafi's chemical weapons to the Syrian opposition to stage an incident that could be blamed on Assad.