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Group One: Essex v Derbyshire, Durham v Worcestershire
Group Two: Middlesex v Hampshire, Somerset v Surrey
Group Three: Glamorgan v Yorkshire, Sussex v Kent
Durham 246 & 204-3 v Worcestershire 213
Will Young is into the nervous nineties against Worcestershire, now on 91 from 210 balls.
He and Jack Burnham have put on 53 for the fourth wicket, with Durham's lead now 237.
Glamorgan 149 v Yorkshire 111-8
Speaking of wickets tumbling, another one has gone down at Cardiff.
England white-ball bowler David Willey is dismissed by Dan Douthwaite for three and Yorkshire, still 38 runs behind, are 111-8.
Joe Root remains unbeaten on 46.
Middlesex 172 & 26-3 v Hampshire 208
And another one - Nick Gubbins this time!
Kyle Abbott now has eight in the match, drawing another edge from Gubbins, and at this rate this match could be over with today.
Middlesex 172 & 22-2 v Hampshire 208
Both Middlesex openers have now fallen at Lord's, with Jack Davis caught behind off Kyle Abbott.
Still the hosts trail by 14 runs and, despite the interruptions, the match continues to hurry along.
Glamorgan 149 v Yorkshire 101-7
Yorkshire have finally ticked past the 100 mark and it's thanks in large part to England captain Joe Root.
Currently on 45 not out, Root's been the only Yorkshire batsman that's looked comfortable at the crease so far today.
Middlesex 172 & 17-1 v Hampshire 208
There's been an early breakthrough at Lord's, with Mohammad Abbas trapping Sam Robson in front for five.
The hosts still trail Hampshire by 19 runs.
Essex 413-3 dec v Derbyshire 73-4
Breakthrough for Essex as Alex Hughes is stumped by Adam Wheater off the bowling of Simon Harmer.
Hughes (22) had but on a handy 46-run partnership with Brooke Guest who remains not out on 32.
Glamorgan 149 v Yorkshire 91-7
And now Jordan Thompson falls, trapped leg before by Michael Hogan.
He falls for 12. David Willey is the latest to join Joe Root out in the middle.
Middlesex 172 v Hampshire 208
An untimely shower has delayed the resumption after lunch at Lord's, but the players are now back out on the field and we should have some more play again very shortly.
Glamorgan 149 v Yorkshire 91-6
A great big wallop from Jordan Thompson who smashes a Michael Neser delivery down the leg-side for a maximum.
He's now moved onto 12, Joe Root is also unbeaten on 36. A little bit of a fightback from Yorkshire here.
Durham 246 & 162-3 v Worcestershire 213
The afternoon session gets started at Chester-le-Street.
Somerset v Surrey 206-4
We managed just nine overs before the rain came at Taunton and, with the bad weather set in for the day, they've decided to call it off early.
Glamorgan 149 v Yorkshire 78-6
And a first-baller for the debutant Harry Duke too!
Michael Neser has his five-fer and Yorkshire remain in deep trouble.
Sixteen wickets have now fallen in fewer than 85 overs.
Glamorgan 149 v Yorkshire 78-5
The wickets continue to tumble at Cardiff - in between all the rain breaks - as England spinner Dominic Bess now falls for 20.
Michael Neser has figures of 4-17.
Joe Root remains unbeaten on 35, with Yorkshire still trailing by 71.
Middlesex 172 v Hampshire 208
In a match during which batting has been difficult, Keith Barker (84 off 116 balls) found license to hit out near the end of the Hampshire innings to give them a crucial 36-run lead.
He hit poor Tim Murtagh for 18 in one over. The same Murtagh who had previously taken 3-30 off 15 miserly overs. His innings included nine fours and four sixes.
Hampshire started the day 41 runs behind with three wickets left and Middlesex would have understandably expected a first-innings lead of some sort.
Because batting has been such a lottery at times, that 36-run lead will way heavily on Middlesex when they bat for a second time.
Somerset v Surrey 206-4
In less positive news...
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Just as we reach lunch at Chester-le-Street, two further matches - at Cardiff and Chelmsford - get under way for the first time today.
Anyone fancy bringing me a sandwich? It looks like I'm going to be sat here until the close.
Durham 246 & 162-3 v Worcestershire 213
And we also break in the north east.
Durham's session even with that late wicket of Bedingham. Their lead is 195.
Middlesex 172 v Hampshire 208
They've now taken lunch at Lord's too. Play will resume at 13:40 BST all being well.
Yorkshire 69-4 v Glamorgan 149
Joy at last!
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