Hampshire make three changes from the side which beat Durham in the quarter-final.

Sonny Baker, Bjorn Fortuin and Ali Orr are in and Hilton Cartwright, Brad Wheal and Liam Dawson make way.

Northants stick with the same XI who got past Surrey in their quarter-final.

Gary Smee
BBC Sport at Edgbaston

The initial announcement said the game had been reduced to 19 overs, but they've bumped it back up to 20 a side.

It's going to be a long day - I didn't need to start thinking about a 5.4 over Powerplay!

It's 20 overs a side and James Vince has won the toss and decided to bowl on account of the possibility of a bit of weather around later.

Northants will not be too bothered with that decision as of the nine matches they have won in this competition, they have won eight batting first.

Gary Smee
BBC Sport at Edgbaston

They're going to start this second semi-final in 25 minutes!

Toss coming up in five minutes.

The game has been reduced to 19 overs a side - I kind of get it because of the tight schedule, but it seems a bit silly.

Gary Smee
BBC Sport at Edgbaston

Both sides are warming up on the outfield in bright sunshine. The umpires are taking a look at conditions...

Image source, Rex Features

Northants enter this second semi-final as underdogs but appear happy enough in that role after upsetting similar odds against Surrey in their quarter-final.

Former England old boy Ravi Bopara, now 40 and old enough to have played in the inaugural T20 competition (then the Twenty20 Cup) back in 2003, was pivotal to that seven-run victory.

His 105 from 46 balls rolled back the years and put Surrey on the backfoot from where they never recovered.

The Steelbacks, who have won this twice in 2013 and 2016, have been cannily led by David Willey throughout the tournament.

And in Ben Sanderson and George Scrimshaw (26 wickets each) they have two of the Blast’s leading bowlers.

What they will not have is Matt Breetzke, the hard-hitting South Africa batter who they hoped would be available for Finals Day but has returned home for personal reasons.

Coach Darren Lehmann admitted that was “bad news” but captain Willey is confident they have the firepower to cover.

"Three games, Edgbaston, one of the best atmospheres in the world, and it is a special place to go and play,” said Willey. “Hopefully the weather stays fair and we can go there and do something special.”

Gary Smee
BBC Sport at Edgbaston

The sun's out and they're peeling off the covers.

Image source, Getty Images

Hampshire are making a record equalling 11th appearance at Finals Day (a record they share with Somerset) but no one in the Hawks dressing room is banking on past history.

Three times when they have made the final they have won it, but the Hawks have also experienced the agony of seven losing semi-finals.

Despite being the bookies' favourites to progress to a fifth final, bowler Chris Wood conceded the form book can go out of the window in the heat of the Blast finale.

Wood told BBC South Today “Two of those three finals have come down to the last ball. We like to put on a crazy game of cricket, hopefully it isn't as crazy as that at the weekend and we can get to the final.”

Openers Toby Albert, Chris Lynn and Hilton Cartwright were instrumental in getting Hampshire to Edgbaston with half-centuries in the quarter-final against Durham, a match they won by 26 runs.

But plenty of responsibility falls on captain Vince’s shoulders with the now Dubai-based freelance cricketer hoping to add to his 463 runs in the tournament so far.

With one semi-final out of the way, let's start to look ahead to the second between Northants and Hampshire, even if the start is going to be delayed.

If we can get started by 15:00 BST then we will still have 20 overs side - if not then we're looking at a reduced game.

Gary Smee
BBC Sport at Edgbaston

It's a pretty gloomy scene at Edgbaston with the full covers still on.

We were meant to be starting the second semi-final between Northants and Hampshire in five minutes.

There is some blue sky where the weather is coming from though.

Image source, Gary Smee

Somerset's Tom Kohler-Cadmore speaking to BBC Radio Five Live Sports Extra:

"We spoke about someone being man of the match and getting us through and thankfully that was me.

"They got off to such a good start and a few boundaries at the end could have hurt us.

"But we've got great vibes now heading into the final and there's some unfinished business from last year."

Lancashire captain Keaton Jennings speaking to BBC Radio Five Live Sports Extra:

"Overall they were they better side on the day and we fell a little short with bat, ball and in the field.

"It feels like a harsh decision to retire George [Balderson] but we felt like Tommy [Hartley] had a better chance to hit a couple of sixes."

Stephen Moore
Former Lancashire opener on BBC Radio Lancashire

Lancashire will be hurting after that. At the halfway point in the run chase the game was theirs to lose. They had the game under control and didn't have to do anything drastic.

They were ahead of the run rate but with both ball and the bat that little bit of inexperience and that little bit of lack of composure in the critical moments meant they have come up well short.

Gary Smee
BBC Sport at Edgbaston

The bananas and bandits are now huddled together at the back of the Hollies Stand under the roof.

The rain does appear to be stopping but it'll take a while to clear things up.

Mark Davis
Former Somerset seamer on BBC Radio Somerset

The out-cricket was excellent from Somerset. They just need to have a little chat about what they're going to do in the powerplay because they were taken down.

They went for 73 and they have got to have a thought process to stop that happening again.

You feel for Lancashire as they had three key players out, Somerset had three out as well but you can only play what's in front of you. It was a decent game of cricket.

Gary Smee
BBC Sport at Edgbaston

The rain is torrential and the full covers are on. I think it'll be a passing shower, but the second semi-final between Northants and Hampshire will definitely be delayed.

Michael Carberry
Former England batter on BBC Radio 5 Sports Extra

Overall it was a great game.

Your heart goes out to Lancashire with their selection issues but they went about their chase manfully with a young squad.

But Somerset showed their experience of big finals and once they got past 160 you wondered how Lancashire would get past that.