Of course I have no way of knowing exactly when the US will hit Syria or even if they will. Obama could still use this as a way of showing he is not a war president and accept the evidence that his rebel chums could be responsible. However the consensus, even from the left, is that a strike of some sort is imminent.
I can remember back when Bush was formulating a response to Afghanistan's refusal to hand over Osama Bin-laden and there was rampant speculation over when the first bombs would begin falling. I was listening to Rush Limbaugh as he let the following slip:
"America has this thing about going to war on a new moon."
I don't recall hearing confirmation if the war began on a new moon or not but if Limbaugh's theory holds then the next new moon is Sept 5th. Will Obama wait that long?