The Repco Supercars Championship could encounter a generation-first this weekend, if weather forecasts come to fruition.

Racing under lights has become an annual occurrence for Supercars since the concept’s 2018 return at Sydney Motorsport Park.

Two night races are scheduled for this weekend’s Armor All Sydney SuperNight at the same location – and rain could throw an extra spanner in the works.

The prospect of racing at night in the rain would be a first for the championship, and Walkinshaw Andretti United driver Chaz Mostert believes it could make for an action-packed affair.

“If the rain arrives like it’s meant to on Sunday, the night race will definitely be one to watch, make sure you are tuned in,” he said.

Minimal rain is expected for the first half of the two-day event tomorrow, but up to 15mm is forecast for Sunday.

Mostert in general is hoping to make a step forward from SMP1, where he ran in the back half of the top 10 almost all weekend.

“Looking forward to getting back out there this weekend. We had a heap of data to work our way through from the weekend, which has been good to look through,” he added.

“It’s not often you can get back out on the same track a week later, so really excited to see what we can achieve from Saturday.”

WAU will expand to three cars this weekend, with Kurt Kostecki (as well as Tickford Racing’s Thomas Randle) completing his third and final wildcard round of the year.

“Really excited to get back behind the wheel of the #27 this weekend,” said Kostecki, the older brother of Matt Stone Racing driver Jake.

“The new livery looks awesome in the flesh, so it’ll be a standout.

“Obviously we are coming in with one less week of laps than the field, but it was awesome to be around the team in the garage at the first event so I think that’ll definitely help.

“It’ll be a big weekend, with not much time to take a breath but I can’t wait.”

Bryce Fullwood is the other driver in the WAU line-up, with the Territorian out to recover ground after slipping to 18th in the championship.

Action will begin tomorrow with Practice 1 from 13:55 local time/AEDT.