England Test captain Alastair Cook made his third century in four matches this season, backed by a ton from Tom Westley, as Essex continued to build a big first-innings score at Worcester.
Resuming on 144-1 after a rain-hit first day, Essex were again hampered by the weather, progressing to 335-2.
Westley, 70 overnight, moved on to complete his second Championship ton of the season before going lbw for 125.
But it was again the only wicket of the day, Cook finishing on 130.
No play was possible because of bad light and rain from 12:20 BST onwards in a truncated morning and they then lost the entire second session.
When they then resumed after tea for the final 28 overs of the day, Essex lost England Lions man Westley after he had put on 222 with Cook.
It was a second wicket for Worcestershire’s new signing, New Zealand international Matt Henry, 29 hours and 50 minutes after his first when he had Nick Browne caught behind the previous morning.
But all-rounder Ravi Bopara came in to make 48 in a so far unbroken third-wicket stand of 97 with his former England team-mate Cook.
Cook finding the right recipe for Essex
This will be Alastair Cook’s last game for Essex before the forthcoming Test series against Sri Lanka.
The series start at Headingley on 19 May and he will not play for Essex in next week’s three-day game against the tourists.
But he will go into the series in fine form, having so far plundered 453 runs in four matches. Prior to this, Cook made 105 and 35 not out against Gloucestershire, then 1 and 127 not out against Sussex, followed by 65 against Northamptonshire.
His 17th first-class century for Essex is still some way short of his record 28 for England.
Cook looks in ‘magnificent’ form – Rhodes
Worcestershire director of cricket Steve Rhodes told BBC Hereford Worcester:
“Cook has been magnificent. He has got his third century of the season, 450 runs in four games and has looked fantastic.
“That’s a good sign for England. He is one of the few players these days who knows how to bat for a day. He stuck to his game plan.
“He played some nice drives later on as well as showing great concentration, so that made life difficult.
“I don’t think we bowled that badly. We’ve gone for about three and a half runs per over. If we’d bowled badly we would be staring down the barrel of 400 already.”
Essex century-maker Tom Westley:
“It is a fantastic start to the season for me. It is nice for me to continue this.
“Sometimes in the past I’ve had a couple of good games and then just drifted a little bit in the few games after that.
“It might be something as I’ve got older and more mature that I’m better equipped to deal with.
“It’s been a brilliant start for me and Essex, obviously top of the league, so things are going well.”