In the longer time-frame ES is in a strong position if it holds above the major Support at 4353. Mechanically, a RTH close below 4509.75, dashed line, Monday’s Buying Day low, would be the first indication of weakness on this time-frame.
In the short-term (today) I’m watching price relative to 4605, the 10day control. If ES cannot assert itself above that level within first hour RTH I’d take that as a minor sign of weakness.