Worcestershire experienced a challenging time with the ball and in the field on a truncated opening day to the LV=Insurance County Championship match with Yorkshire at New Road.
Jake Libby won the toss and put the visitors into bat in conditions which looked helpful for seam bowling.
However, Yorkshire openers Adam Lyth and Finley Bean put on an unbroken 154 in 33.3 overs before rain prevented anymore play after 2pm.
Matthew Waite was the pick of the Worcestershire bowlers in his first Championship appearance against his former county.
The all-rounder posed plenty of questions, conceded just 21 runs in 10 overs and also saw two chances go to ground off his bowling.
But it was a day where the remainder of the attack found it a challenge to consistently bowl the right line and length and a total of 25 boundaries were scored.
By the close Lyth was unbeaten on 77 from 108 balls with 15 fours and Bean 69 not out from 97 deliveries with 10 boundaries.
Worcestershire were without skipper Brett D’Oliveira due to the impending birth of his second child but Jack Haynes returned after missing the previous Championship game against Derbyshire with a knee injury.
Lyth and Bean survived a couple of early scares but scored freely against the Kookaburra ball which is again being trialled in this round of Championship matches.
Bean survived a chance to gulley on 28 off Adam Finch and then on 41 was put down at first slip off Matthew Waite.
Waite also saw Lyth on 41 put down a chance to second slip. He then cracked the next ball through the covers for four to complete 13,000 first class runs.
Yorkshire reached 132-0 off 27 overs in the morning session but there was only time for two more brief sessions of play.