Speaking of rain, it's also falling heavily at Crewe.

The Alex are due to host Colchester in League Two at 15:00 GMT, although as this video from BBC Essex shows, they might need to get forking the surface at Gresty Road...

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More encouraging signs for the visitors. Tom Ince, Johnny Russell and Craig Bryson are all beginning to get on the ball but Forest are standing firm. 

Ben Osborn's heatmap will be interesting. The Forest man will need a long, long rest to recover if he carries on at this pace. He's been everywhere.

It's really tipping down at the City Ground. And dare I say it, conditions that are often conducive for red cards when it's a derby.

This match often sees a sending-off. You have been warned.

Derby force a couple of corners, the second of which sees home keeper Jordan Smith drop the ball as he collects under pressure. 

Bradley Johnson knocks the ball into the net after the whistle has gone. Is that a let-off?

Moments later Tom Ince blasts an effort off target after some neat interplay on the edge of the area. Derby showing signs of settling.

Forest are showing all the signs of a Mark Warburton side so far. Neat, tidy, full of confidence and posing a threat.

Derby are nothing like a Gary Rowett side just now, but fully expect that to change because the half-time teamtalk could be interesting in the Rams' dressing room.

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Andrew Aloia
BBC Sport at the City Ground

With the rain coming down, Mark Warburton is one soggy picture of a manager. A happy one, it must also be said.

After taking in much of the opening 20 minutes from the dugout, Gary Rowett emerges to make a few hurried points to his under-siege Derby players.

Blackburn came close a few minutes ago when Lucas Joao headed straight at Chris Maxwell in the Preston goal.

However, Preston remain dangerous on the counter attack and Rovers need to be wary of the combination between Tom Barkhuizen and Jordan Hugill, who has just had an effort cleared from a free-kick.

Forest's 17-year-old striker Ben Brereton is another man making a good impression, but it's tricky to think of a home player not having a good game so far.

Derby are second best, there's no doubt about it.

Ben Osborn has been a busy man. The Forest midfielder is at the other end having another attempt on goal.

And moments later team-mate Britt Assombalonga's ball into the box comes back off the bar. It's all Forest just now.

Andrew Aloia
BBC Sport at the City Ground

After that magnificent start by Forest, the home fans have their full voice behind every touch and pass.

A very slick start to the Mark Warburton era at the City Ground.

Image source, Dan Westwell

Preston could have had two there.

Daryl Horgan's corner is only cleared as far as Aiden McGeady, who lashes a volley over the top of the bar. North End very much on top right now after a slow start.

Matej Vydra and Johnny Russell combine to pose the first real moment of danger by Derby as we go past the 15-minute mark.

But Ben Osborn intercepts and the danger is averted before we see a shot.

Tom Barkhuizen is a man in form right now and Blackburn can do nothing to stop him.

The Preston forward latches onto Tom Clarke's long ball forward, plays a one-two with strike partner Jordan Hugill, finds some space with his blistering pace and scores his fifth goal in four starts for North End.

Could Tony Mowbray be on his way to a first defeat as Blackburn manager?

Britt Assombalonga, back in the Forest side today, is making a nuisance of himself up front.

Zach Clough has the goal but Assombalonga's presence is making a big difference in the early stages as the rain teems down in Nottingham.

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Derby are really finding things tough. Gary Rowett's side haven't had a sniff of goal yet and have barely managed to string more than a couple of passes together.

Andrew Aloia
BBC Sport at the City Ground

Zach Clough sent the City Ground into raptures with a fine prodded first-time finish from inside the box to beat Derby goalkeeper Scott Carson.

It was a marvellous cross from Daniel Pinillos from the left. The Rams caught completely unawares.

It's safe to say that while it's been an exciting start in the East Midlands, in the East Lancashire rain it's a different story.

Two successive corners for Preston come to nothing as both sides have yet to have a meaningful attempt.

Nottingham Forest midfielder Ben Osborn smacks a shot over the bar as the ball falls kindly to him on the edge of the box.

Forest are full of confidence now.

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Four minutes in and Zach Clough has scored for Forest. A perfect start for the hosts.

Daniel Pinillos crosses the ball in and no one picks up Clough. His run into the box is rewarded as he finishes calmly.