Morris was nearing his century and Glamorgan's overall lead had reached 300 to leave every prospect of a result on a pitch which had already proved to be to Robert Croft's liking.
But then three things happened in rapid succession. First, Morris, fluent and belligerent until he reached his mid-nineties but unaccountably bogged down at that point, lost his wicket.
Then Matthew Maynard came to the wicket, only to declare 10 minutes before the scheduled time for lunch in order to give his side the maximum length of time in which to bowl Yorkshire out.
But then the clouds that had been rolling heavily over the rugby league stand assumed battle formation and the rain that had washed out the whole of Thursday's play resumed, this time with ominous finality.
It was unfortunate for Glamorgan who had done their utmost to manoeuvre themselves into a winning position. They had set about building up a declaration target with gusto, Morris and Stephen James showing why they are, on the evidence of the season so far, the most productive opening partnership in the County Championship.
James, the scorer of a century in the first innings, continued in the same vein until, on 52, he misjudged a delivery from Richard Stemp. Attempting to sweep, he misread the line and was bowled behind his legs.
That hardly slowed Glamorgan's progress. Morris virtually monopolised the strike and spread the ball all around Headingley, with his straight driving and a couple of sweetly timed late cuts a particular delight.
He showed a destructive fondness for the occasional off-spin of Michael Vaughan, but the bowler eventually had his revenge. Reduced to pushing and prodding his way towards his hundred, Morris judged the line wrongly and was bowled by one that might have done a little more than he expected.
That in itself was encouragement for the watching Croft, but the clouds closed in, the covers came on and all bets were off.Reuse content