England wicketkeeper Tim Ambrose hit 86 not out as Warwickshire's bid to claim the Division Two title started well against Glamorgan at Edgbaston.
Already assured of promotion, the hosts secured two of the four points needed to win the division by posting 270-7.
Glamorgan had reduced Warwickshire to 86-4 with Adam Shantry taking 3-54.
But Ambrose and Jim Troughton (54) put on 101, and then Ambrose and Neil Carter (42 not out) led their side forward before bad light ended play.
Amid gloomy conditions at the start of the innings, Shantry consistently swung the ball for figures of 2-18 in eight overs.
Navdeep Poonia inside edged a catch behind the wicket and Darren Maddy was lbw when Shantry switched to the City End.
Tony Frost, a double century-maker at Chelmsford last week, made 23 before his middle stump was knocked back by Jason Gillespie and a promising knock by Jonathan Trott ended on 37 when he was leg-before to Shantry's seventh ball after lunch.
With the sun breaking through, batting seemed to become easier as Ambrose cut and drove with telling effect.
Troughton played his part by reaching 50 from 77 balls and then went for 54 when beaten by a full length ball from David Harrison.
Making his home debut, Rikki Clarke failed to score before the same bowler cut one back into his pads.
Robert Croft briefly got in on the act as Ian Salisbury became the fifth lbw victim of the day, but Carter rallied with his 42 coming off 52 balls before 20 overs were lost because of bad light.
With Carter monopolising an unbroken stand of 58, Ambrose became more circumspect and should have gone for 85 when Michael Powell failed to hold a firm cut off Ryan Watkins at backward point.
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