A pretty big number will hang over the Democratic convention as it kicks off in North Carolina's Time Warner Cable Arena on Tuesday. 

That's the day the official debt clock is expected to show the U.S. debt crossing the $16 trillion mark. 

The counter, on the Treasury Department website, is on pause for the Labor Day weekend. The last update was Thursday afternoon, putting the figure at $15.99 trillion. 

The figure should pass $16 trillion on Tuesday, which comes after Republicans made the skyrocketing debt a theme at their convention in Tampa. 

The GOP convention featured two debt clocks -- one showing the total national debt and the other showing the amount of debt added during GOP convention week. The latter clock stopped, after Mitt Romney's nomination address Thursday night, showing $8.54 billion added to the debt during those four days alone.