Weather playing a role in Sunday’s championship race at Homestead-Miami Speedway

Weather may play a factor in Sunday's NASCAR Sprint Cup Series championship race at Homestead-Miami Speedway. 

Jeff Curry

Editor’s note: Updated at 2:30 p.m. ET

Despite a rain shower that began around 2 p.m., the forecast for this afternoon’s season-ending Ford EcoBoost 400 at Homestead-Miami Speedway is positive, providing hope that the race will be run in its entirety.

As of 2 p.m. ET, weather.com is predicting a 30 percent chance of rain at 3 p.m., when the race is scheduled to start. That probability drops to zero at 4 p.m. By 7 p.m. it rises to 15 percent and stays there until 11 p.m. That should allow plenty of time to get the race in, even if there is a delay or two along the way.

That’s great news, given that this race will decide the 2015 NASCAR Sprint Cup Series champion from among Kevin Harvick, Jeff Gordon, Kyle Busch and Martin Truex Jr. 

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NASCAR chairman and CEO Brian France said Friday that NASCAR will not alter its procedures because this is a championship race. So once the race hits the halfway point — in this case, 134 of 267 laps completed — it will be considered official.

"We typically want to come away on race day with whoever watched the race, watched the event, saw the conclusion of that event," said France. "And that’s if you are over 50 percent. … Our view now is that like a lot of things that aren’t necessarily perfect, so to speak, that’s part of the game. That’s part of racing that it’s part of the strategy. You saw that last week in Phoenix. That you have to anticipate weather as being a factor in deciding things, as unfortunate as that is. Hopefully it won’t be a factor on Sunday."

Heavy rain overnight at Homestead means track conditions will be different Sunday than they have been all weekend. And teams are keeping a close eye on the weather.

"It’s going to be pretty volatile," said Alan Gustafson, Gordon’s crew chief. "I don’t really know what to do about it. We will have to play it by ear and see what happens. It’s going to be tough for everybody involved, all the competitors, the Chaser’s, NASCAR, we will just work through it. It’s South Florida, it could clear up and we could have no problem, but right now it looks like there will be some weather in the area."

"I don’t know that you can have a strategy for the weather," added Busch’s crew chief, Adam Stevens. "Thunderstorms can pop up so fast that you’ve got to keep an eye on it. It really doesn’t make a difference until you start approaching halfway and the rules are the rules so we’re aware of that. I think it’s just something you’ve got to play by ear because the weather is really hard to predict down here."

FOXSports.com will update the weather forecast periodically throughout the day.