Daytona 500 rain update: What's the forecast for Speedweek Saturday, Sunday's big race?

With roughly 24 hours left before a full slate of Saturday races on the way to Sunday's running of the 66th Daytona 500, the weather forecast for the big Speedweek weekend is still less-than-promising, with high chances for rain on both Saturday and Sunday.

The Daytona ARCA 200 was moved up from Saturday to Friday night. Here’s the latest update on rain chances for the weekend that could impact the United Rentals 300 on Saturday, as well as the Great American Race on Sunday:

Will it rain on the Daytona 500? What about Saturday's races?

The latest update to forecast models now call for an 80% chance of daytime showers on Saturday, increasing to a 90% chance of rain Saturday night into Sunday morning in Daytona Beach, according to meteorologists at the National Weather Service in Melbourne.

That doesn’t bode well for a full slate of Saturday races that includes a Cup Series final practice (10:30-11:20 a.m.); Xfinity Series qualifying (11:30 a.m.); and the Xfinity Series, United Rentals 300, at 5 p.m. The ARCA Menards Series race scheduled for Saturday was moved up to Friday night.

"The forecast models now call for 1-3 inches of rain through the weekend, from 7 a.m. Saturday to 7 a.m. Monday, with localized flooding by up to 4 inches of rain possible," said Kole Fehling, meteorologist with the National Weather Service in Melbourne.

"Definitely, the guidance has come into agreement that the heavier rainfall will be over Central Florida and, unfortunately, the Volusia County area, especially along the coastal areas, could get up to 4 inches," he said.

For the 2:30 p.m. Sunday running of the Daytona 500, rain chances have now increased to 70% after dropping to 50% late this week, according to the NWS extended forecast.

"That's the biggest change in the forecast," Fehling said. "There's now a better chance for rain on Sunday. There could be some breaks into Sunday morning, but another round of moderate to heavy rain is possible into the late afternoon."

What factors are contributing to rainy weekend forecast for Daytona 500?

The high rain probability is tied to a cold front that is expected to sweep across the area Saturday into early Sunday morning, according to the NWS.

As the front arrives, weekend temperatures are expected to reach highs in the upper 60s on Saturday and a bit cooler, in the lower 60s, on Sunday. Nighttime lows are forecast to be in the 50s. In addition, winds out of the northwest are expected to be breezy on Sunday, with gusts of 40 mph possible during the strongest showers, Fehling said.

Daytona Beach weather radar

Here's the daily weather forecast for Daytona 500, NASCAR Speedweek races

Friday: Partly sunny, with a high near 75. West wind 5 to 10 mph becoming east southeast in the afternoon. A 40% chance of showers after 4 a.m., with a low around 58.

Saturday: Showers, mainly after 1 p.m., with rain that could be heavy at times. Chance of precipitation is 80%, with new precipitation amounts between a 1/10 and 1/4 inch possible. At night, rain chance increases to 90%, with heavy rain expected at times. Low around 54.

Sunday: Showers likely, mainly before 1 p.m. , with a 70% chance of rain. High near 60. Windy, with a north wind of 15 to 20 mph, with gusts as high as 25 mph. At night, a 30% chance of showers, mainly before 1 a.m. A low around 50. North wind around 15 mph, with gusts as high as 25 mph.

Monday: If Daytona 500 is postponed, the Monday forecast calls for mostly sunny skies, with a high near 61. North wind around 15 mph, with gusts as high as 20 mph. Mostly clear at night, with a low around 49. North wind around 10 mph.

Daytona 500 schedule: Here's a look at Speedweek events

Friday, Feb. 16: ARCA Menards Series qualifying, 1:30 p.m.; Craftsman Truck Series qualifying, 3 p.m.; Xfinity Series practice, 4:35-5:25 p.m.; Cup Series practice, 5:35-6:25 p.m.; Craftsman Truck Series, Fresh From Florida 250, 7:30 p.m.; ARCA Menards Series, Daytona ARCA 200, 10:30 p.m.

Saturday, Feb. 17: Cup Series final practice, 10:30-11:20 a.m.; Xfinity Series qualifying, 11:30 a.m.; Xfinity Series, United Rentals 300, 5 p.m.

Sunday, Feb. 18: 66th Daytona 500, 2:30 p.m.

How to watch Daytona 500, NASCAR races during Speedweek

Here's where you can catch this week's racing action during Speedweek and the 500:

Friday: Truck Series race (Fresh From Florida 250), 7:30 p.m. (FS1); 200-mile ARCA Series race, 1:30 p.m. (FS2, FS1)

Saturday: Xfinity Series' United Rentals 300, 5 p.m. (FS1)

Sunday: Daytona 500, 2:30 p.m. (Fox)

This article originally appeared on The Daytona Beach News-Journal: Daytona 500 weather: Latest rain forecast for NASCAR race weekend