When the match finally started, the first four sessions having been lost to the weather, Sussex eagerly took up the option to bowl but the home side reached 284 for nine - heady heights on a day of desperate batting travails elsewhere in Division Two.
Sussex bowler David Wiese, who took four of the wickets, said: "It was nice for me to get back out there again and in red-ball cricket too as I've played a lot of white-ball lately. It was good to get some wickets. It was coming out decently to start with though it turned out to be a bit of a long day in the end.
"It's a good cricket wicket. There is something in it for the bowlers with a bit of nibble if you put it in the right place, but it's a good pitch and the batsmen will get value for their shots when the outfield dries out. The outfield probably cost Warwickshire 20 or 30 runs today."
With both sides starved of match practice after the rain-ravaged pre-season, batsmen and bowlers alike were clearly feeling their way into the season.
Of the batsmen, only Ambrose (76 not out, 106 balls, ten fours) and Bell (70, 91 balls, 14 fours) found any fluency. For others it was a case of cobbling together runs against a Sussex attack which, led by Wiese (four for 50) delivered its share of good balls without the consistency of performance that comes with regular cricket.
Both sides have begun the campaign with new captains - Jeetan Patel and Ben Brown - and the latter did not hesitate to give his bowlers first use of damp conditions after a rain-haunted week.
With Jofra Archer away on IPL duty, Sussex have shored up their seam attack by signing Ishant Sharma and the Indian star took just 18 balls to open his account when Will Rhodes, making his Warwickshire championship debut, edged into the slips. Five balls later, Dom Sibley tickled a rising ball from Ollie Robinson to the wicketkeeper and the home side was 20 for two.
Bell and Jonathan Trott added 60 in 17 overs before the latter edged an excellent delivery from Wiese to first slip. Sharma trapped Adam Hose lbw and Sam Hain was adjudged lbw, playing no shot, to Wiese but Bell, fresh from a century against Durham MCCU, was in fine touch, advancing to 50 from 66 balls with ten fours.
On 56 at tea, he resumed with three gorgeous off-side boundaries in quick succession to pass his career-average against Sussex (62.76). It was a surprise to all when his next attempt to pierce the offside field sent a catch to point off Wiese.
Former Sussex player Ambrose and Keith Barker dug in to add 52 in 16 overs before Stuart Whittingham induced edges from Barker and Patel in quick succession. Wiese returned to remove Olly Stone courtesy of a brilliant catch at second slip by Harry Finch. That was 220 for nine but Sussex were frustrated by last pair Ambrose and Chris Wright (17 not out from 70 balls) who added an unbroken 62 in 19 overs as the shadows lengthened in glorious evening sunshine.