Ian Westwood scored 120 as Warwickshire took a lead against Middlesex on the second day of their County Championship game.
Warwicks resumed on 21-0 and Westwood and Chopra put on 175 before Chopra went for 56.
When Westwood went for 120, Jim Troughton battled bravely at the other end for 50, whilst his parters at the other end lost their wickets cheaply.
When the rain came down, Warwicks were 293-8, some six runs ahead.