It was hardly a quick scoring session with Notts adding just 91 in 29 overs. However, the host county did enough to suggest Worcestershire might have to chase in excess of 300 to register their second Division One victory of the season.
Samit Patel was the only wicket to fall after lunch, trapped lbw on the back foot by Saeed Ajmal for 31, off 69 balls.
He and Chris Read put on 33 for the sixth wicket with Read and Brett Hutton adding an unbeaten 66 for the seventh.
In muggy conditions, Worcestershire found it increasingly difficult to impose themselves and at tea, Notts had reached 300 for 6 with Read, having passed 50 off 82 balls, unbeaten on 52 and Hutton 26 not out.
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A lead of 257 looks more than useful with four sessions remaining, although director of cricket Mick Newell will be keen to see his batsmen take the target past 300.