UPDATE: Click here for Sunday's weather report.

Update: 4:30 p.m.

Two rounds of storms are expected to bring severe weather for tomorrow's Indianapolis 500, but a dry window is expected to open up in the middle of the afternoon, according to the National Weather Service in Indianapolis.

The question is whether the pause in rain will be long enough to accommodate some or all of the race.

The first round of storms is expected to hit during the late morning or early afternoon hours, with a threat of damaging winds that could gust up to 60 to 70 mph.

The timing could threaten early activities at the Indianapolis Motor Speedway. The green flag that starts the race is scheduled for 12:45 p.m.

The latest forecast, however, should give race fans some hope.

"We're going to have at least a three-hour window, we think, where there's not going to be any thunderstorms during the mid to late afternoon," said Andrew White, a meteorologist with the National Weather Service in Indianapolis, during a Facebook Live update at 4:30 p.m. Saturday.

He said that "solid dry window" will likely open between 3 p.m. and 6 p.m., but could start as early as 2 p.m. and last as late as 8 p.m.

The updated forecast could leave enough time to complete the race, which typically takes about 3 hours. It's considered official after 101 of the 200 laps, which means 90 minutes of favorable weather can be enough, along with at least 90 minutes to dry the track.

The second line of storms is expected to be more severe, White said.

"The second round is really the main one that we're going to be concerned with," he said, "with the potential for more widespread and intense damaging winds, potential for some large hail and then that tornado potential is there as well."

The tornado threat will likely to stay south of the Indianapolis area.

"We're not expecting strong tornadoes tomorrow," White said. "Most of the tornadoes we'd be seeing with this kind of a setup would be on the weaker end, within the area of damaging winds. So thankfully, that's not going to be one of the greater concerns for tomorrow. But we do need to keep an eye out for it."

White also wanted to remind people that lightning can be dangerous, even from a distance.

"Anytime you see a flash, we want you to dash inside," he said, "or when you hear thunder roar, go indoors."

Update: 1:15 p.m.

The chance of rain — including severe storms — remains high for tomorrow's Indianapolis 500.

"We do have pretty high confidence we're gonna see some storms through the day on on Sunday," said Jason Puma, a meteorologist with the National Weather Service in Indianapolis.

"The precise timing is a little in question," he said, "But right now we're pretty sure that we're gonna see some storms in the area between 10 a.m. to 3 p.m."

The storms could pack a serious punch.

"There is an enhanced risk for severe weather across the area tomorrow," Puma said. "So that means some of these storms could contain damaging wind gusts up to 60 or maybe even 70 miles an hour. Large hail will be possible, torrential rain, and we can't even rule out an isolated tornado."

The timing isn't great for the race. The green flag is scheduled to begin the race at 12:45 p.m. The race typically takes about three hours, but is considered official after 101 of the 200 laps. That means about 90 minutes of favorable weather can be enough.

Puma said a dry period is possible after the first round of storms moves through, but that might not be until after 3 or 4 o'clock.

Accuweather has increased the chance of precipitation in its forecast to 90%.

Earlier:

As anticipation grows for tomorrow's Indianapolis 500, so do questions about the weather. To get ready for the main event, IndyStar is keeping race fans updated with the latest forecasts.

The question isn't so much if it will rain tomorrow, but when and for how long.

"We are expecting rain tomorrow," said Jason Puma, a meteorologist with the National Weather Service in Indianapolis.

The gates open at 6 a.m. Sunday and the green flag is scheduled to start the race at 12:45 p.m. Here's what's in the forecast for Indy 500 weekend as of May 25, 2024:

What will weather be like for the Indy 500?

There is a 90% chance of rain throughout the day on Sunday, Puma said. The National Weather Service is expecting scattered showers before 11 a.m., followed by thunderstorms.

"The chances essentially look the greatest between about 11 a.m. and 2 p.m.," Puma said.

Everything Indy 500: IndyStar's full coverage for this year's race

There will still be a chance of rain before and after that, he said. "We are still trying to determine the timing and the development of these storms as they pass to the area."

The National Weather Service says some thunderstorms are expected to be severe, with damaging winds and large hail. Tornadoes are also possible.

Weather alerts: Indianapolis tornado sirens will only sound during warnings

The temperature is expected to peak at 81 degrees.

Accuweather is predicting an 87% chance of rain and says racegoers should watch for strong afternoon thunderstorms with a "significant risk of flash flooding, large hail, damaging winds and tornadoes."

Weather Underground is forecasting a 70% chance of rain with scattered thunderstorms in the morning, with widespread and possibly severe storms in the afternoon.

2024 Indy 500 weather Should you evacuate the grandstands? What fans can expect if bad weather hits the Indy 500

Will the Indy 500 be delayed or postponed?

Regardless of grim weather outlooks, IMS President Doug Boles said he's 99.9% sure there will be no announcements about postponements or delays before Sunday.

The Indy 500 has had only three complete postponements due to rainy weather since 1915, according to the IMS website.

The last time rain interfered with the big race was in 2007, when drivers were only able to finish 166 laps after having to stop twice from the weather.

Drivers must finish at least 101 laps for the race to be official, according to a 2019 IndyStar article.

Any postponement, either full or partial, will be made up the next day.

What is the weather forecast for Memorial Day if there's a delay?

If the race is postponed until Monday, the weather outlook is somewhat better. There's a 30% chance of rain in the morning, but then partly sunny, dry weather with a high near 75 degrees, Puma said.

What will weather be like for Legends Day?

The forecast is much better for today's Legends Day.

Those going out to the track to grab some autographs can expect partly cloudy conditions with no rain and a high near 78, Puma said.

Indy 500 weather history

IndyStar analyzed 20 years of historic data from Weather Underground for May 26, this year's Race Day.

Daily temperatures averaged in the high 60s and it rained only 5 days out of the last 20 since 2004. Precipitation totals on rainy days were light, with the highest on record at only one-tenth of an inch.

On previous race days not always falling on May 26, temperatures varied wildly from a high of 92 degrees in 1937 and a low at 37 degrees in 1947, according to the National Weather Service.

The most rain fell on May 30, 2004, when Race Day was inundated with nearly 4 inches of precipitation.

Karl Schneider is an IndyStar environment reporter. You can reach him at karl.schneider@indystar.com. Follow him on Twitter @karlstartswithk

IndyStar's environmental reporting project is made possible through the generous support of the nonprofit Nina Mason Pulliam Charitable Trust.

This article originally appeared on Indianapolis Star: Indy 500 weather: Will it rain on race day? Forecast as of May 25