Despite improved conditions, Kent went in at stumps on 24 for two after 12 overs of their second innings – still trailing the visitors by six runs.
Wicketkeeper-batsman Ollie Robinson had made Kent's first-innings best of 37 before he was lbw to Gregory, who claimed six for 32 as the hosts were dismissed for 139 in 41 overs.
— Somerset Cricket 🏏 (@SomersetCCC) June 11, 2019
Somerset, though, failed to make a telling impact with the bat, as they started their first innings of the match by 2.40pm.
The visitors slumped to 14 for three before Tom Banton made 63 to help them edge on to 169 all out. Harry Podmore, Grant Stewart and Matt Milnes all took three wickets.
Zak Crawley became Gregory's seventh victim of the day and Kent opener Sean Dickson was unbeaten on 17 when play finally ended following an extended final session of 38 overs from an action-packed day on which 22 wickets fell.
All play had been washed out in Division One on Monday.
— Yorkshire CCC (@YorkshireCCC) June 11, 2019
Captain Steven Patterson, though, took three wickets in an over as unbeaten Yorkshire looked to make up for lost time and fought back on the second day against Surrey at Guildford.
Hosts Surrey, still looking for the first win of their title defence, had reached 290 for eight when bad light ended play with nine overs not bowled.
Opener Mark Stoneman made 61 and acting captain Ben Foakes 62 while there was also a half-century for Championship debutant Jamie Smith (56).
Patterson, though, did the damage with his impressive spell to finish with four for 71, having struck in his third over with the second new ball.
At Welbeck, there was again no play possible on the third day between Nottinghamshire and Hampshire.
Excessive rain prompted the umpires to make the decision to rule out the chances of any play as early as 9am.
On the opening day of the match, Nottinghamshire were bowled out for 162, with Kyle Abbott taking six for 37. Hampshire had reached 93 for two by the close.
Division Two leaders Lancashire were denied the chance to build on Monday's dominance with the ball as play against Worcestershire at New Road was washed out on day two.
Heavy overnight and morning rain saw the umpires abandon play for the day at 1.25pm.
The previous day, Lancashire had bowled out the home side for 98 in 38.1 overs after an uncontested toss.
Sussex opening batsman Will Beer scored a career-best 76 not out against Gloucestershire at Arundel.
Beer, a replacement for the injured Phil Salt, amassed his unbeaten score from 276 balls.
Conditions improved during the afternoon as Stiaan van Zyl also scored an 89-ball 54 as Sussex reached 257 for five at stumps.
Glamorgan stuttered to 167 for five when bad light stopped play with 24.3 overs remaining of the first day of their match against Derbyshire in Swansea.
There was no play before lunch and following an uncontested toss, Tony Palladino struck with the fourth ball of the innings when he had Nick Selman lbw for a duck.
Although Charlie Hemphrey (32), Australian Test batsman Marius Labuschagne (37) and acting captain David Lloyd (32) tried to push the hosts on, the Derbyshire seamers kept a tight rein as Luis Reece also picked up two wickets.
Ricardo Vasconcelos scored an unbeaten century to put Northamptonshire in a strong position on day two against Durham at the Riverside.
Durham had mustered a score of 253 from their first innings as Ben Raine (82) and Brydon Carse (77 not out) both made half-centuries. Ben Sanderson took four for 55.
Vasconcelos led the Northants response with a brilliant century which included partnerships with Temba Bavuma (43) and Brett Hutton (34 not out) as the visitors reached 254 for six at stumps.
The play was abandoned at Grace Road without a ball being bowled for the second consecutive day between Leicestershire and Middlesex.
Heavy rain persisted throughout the morning, forming large pools on the already sodden outfield at the County Ground, with proceedings abandoned at 1pm.