Isaac has -- fortunately -- been an underachiever so far. The pressure is 992 mb as of a 7:12am measurement. Winds of 65 mph, still a tropical storm, were reported on the 7am advisory but I imagine those are a little on the high side given the rising pressure and the latest report from the Hurricane Hunter aircraft.
The storm may still strengthen as it is moving over very, very warm water and it has favorable outflow. That said, the chances of Isaac becoming a major hurricane are less now than they appeared yesterday at this time.
The eye of the storm should be reaching the mouth of the Mississippi River midday or afternoon Tuesday with increasing winds and rains ahead of the eye.
Today, there is a tornado threat in the indicted areas where 5% is a significant risk.
Tomorrow, the tornado risk significantly increases as the storm's spiral bands move ashore.