The England prospect finished on 119 not out as Somerset were bowled out for 406 in their first innings, with Alviro Petersen's 136 also paving the way to a tough target for the Bears.
Warwickshire then hit early trouble in their reply with openers William Porterfield and Varun Chopra both failing to see through the 14 overs to lunch to leave the champions perilously placed at 24 for two. They were eventually bowled out for 158 with Alfonso Thomas (three for 29) the pick of the bowlers.
Somerset then returned to the middle and were 46 for one at stumps on day two, giving them a lead of 294 with nine wickets remaining, Marcus Trescothick (37) the only casualty.
Derbyshire finished the third day of their clash with Nottinghamshire trailing by 44 runs with five wickets remaining.
Shivnarine Chanderpaul (57) top-scored in the second innings after Nottinghamshire were bowled out for 443, with James Taylor, who was left out of England's Performance Squad at the start of the summer, impressing with a knock of 112.
Derbyshire finished the day on 143 for five after they lost Wayne Madsen (47) and Ross Whiteley (4) late in the day.
Durham took control against promoted Yorkshire after they set them an imposing target of 336 runs to win in their second innings. Yorkshire finished the day on 17 without loss, after Mark Stoneman's innings of 109 and Dale Benkenstein's 61 not out paved the way to a second innings total of 275 for four declared for Durham.
Surrey, meanwhile, are trailing Sussex by 109 runs in their match at The Oval.
Luke Wells scored 208 for Sussex in their reply to Surrey's first innings total of 351, with the visitors eventually bowled out for 526 as Ed Joyce just missed out on his century when left stranded on 98 not out. In their second innings reply, Surrey finished the day on 66 for one, with Rory Burns dismissed by Steve Magoffin for seven.
Northamptonshire and Hampshire look poised to win their LV= County Championship Division Two matches against Gloucestershire and Worcestershire respectively.
Gloucestershire were left on 280 for nine overnight, just 68 runs ahead of the visitors, after Northamptonshire were bowled out for 404 in their innings.
Worcestershire, who were bowled out for 206 in their first innings, were 153 for five as they followed on against Hampshire.
Opening batsman Daryl Mitchell (71 not out) led the way in the second innings as wickets tumbled, with the Pears still needing to score 141 to make Hampshire bat again.
Worcestershire had been bowled cheaply, losing their final five wickets for 53, with James Tomlinson finishing with three for 52.
Lancashire's rain-affected contest with Kent finished with the hosts leading by 112 runs with five wickets remaining in their first innings at Emirates Old Trafford.
Lancashire were 120 for three but they pushed on, with Simon Katich top-scoring with 93 not out with Steven Croft (47 not out) also at the crease in reply to Kent's 244.