Zimbabwe-born Ballance made a chanceless 112, his third century of the championship season, while opener Alex Lees continues to impress in first-class cricket after making 56 to help the league leaders to 294 for nine at the close.
Keith Barker and Chris Woakes both ended the day with figures of three for 61, while Rikki Clarke also chipped in with two wickets after Warwickshire had won the toss.
Steven Finn showed flashes of his best form as Middlesex shaded day one against title contenders Durham at Lord's.
The pace man, dropped after a poor showing in the first Ashes Test at Trent Bridge, showed the selectors what they were missing as England's bowlers toiled at Old Trafford by taking four for 46 as Durham were all out for 143 after losing the toss.
Middlesex slid to 88 for five in reply but captain Neil Dexter led the way with an unbeaten 40, while Gareth Berg, who had earlier taken two wickets, was on 28 not out as they closed on 126 without any further loss.
Sussex were grateful for opener Luke Wells' second century of the season after struggling on a bowler-friendly pitch against Derbyshire at Hove.
The 22-year-old batted for a shade over six hours in his 110 and helped Sussex recover from 144 for five after they had been put in, putting on 45 with Ben Brown and a further 53 with Chris Jordan before the hosts were eventually all out for 314.
Steven Mullaney top scored with 75 as Nottinghamshire were made to battle for every run by a determined Somerset attack at Taunton.
After winning the toss, the visitors fought their way to 327 for eight, with David Hussey contributing 68, while left-arm spinner George Dockrell claimed three for 99.
Paul Horton, Luis Reece and Simon Katich all made half-centuries to put Division Two leaders Lancashire in control against Leicestershire at Grace Road.
Reece fell 15 runs shy of his ton, while fellow opener Horton and Katich contributed 59 and 62 respectively as Lancashire reached 303 for five after opting to bat first.
Hamish Marshall struck his fourth century of the season to propel Gloucestershire to 358 all out after winning the toss at Northamptonshire.
The former New Zealand international hammered a brilliant 145 off 197 balls including 19 fours and two sixes at Wantage Road, while David Willey, Azharullah and Andrew Hall claimed three wickets apiece for Northamptonshire, who closed on 13 without loss.
Hampshire batsman Michael Carberry continued his exceptional run of form with another superb innings but pace bowler Michael Hogan took two wickets late on to help Glamorgan finish on equal terms at the Ageas Bowl.
Hampshire slipped from 246 for four to 261 for six at the close after Hogan had accounted for Sean Ervine and nightwatchman Danny Briggs. The hosts had recovered from four for two earlier on after being put in, with Carberry leading the way before falling six runs shy of a century.
Ben Harmison and Darren Stevens struck 96 and 95 respectively as Kent were all out for 324 after losing the toss against Worcestershire at New Road.