UPDATE: Find the latest weather forecast for Legends Day and Race Day here.

The city is entering the home stretch as the the Indy 500 weekend kicks off with Carb Day today. To get ready for the main event, IndyStar is keeping race fans updated with the latest weather forecasts.

Crystal Pettet, meteorologist with the National Weather Service in Indianapolis, said details for Sunday's forecast are still subject to change. Because the weather outlook is rapidly changing, race fans will need to pay attention to the latest forecast.

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Here's what's in the forecast Indy 500 weekend as of today:

What will weather be like for the Indy 500?

Gates open Sunday for the Big Race at 6 a.m., and the green flag starting the race waves at 12:45 p.m. Here's a breakdown of the day's forecast:

There are increasing chances of rain and thunderstorms, Pettet said, with a wave coming through in the late morning to early afternoon and chances of severe thunderstorms increasing in the afternoon.

The NWS forecast as of Friday gives a 40% chance of rain and thunderstorms before 2 p.m. and an 80% chance after 2 p.m. Pettet said those numbers will likely change, and meteorologists currently are working in 6-hour time intervals, but those will become more granular closer to the race.

"At the moment, the potential for severe thunderstorms look significant for Sunday afternoon and evening," Pettet said Friday morning.

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The Weather Underground's current forecast for Sunday predicts thunderstorms beginning at 11 a.m. and lasting throughout the day. The forecasters there say severe thunderstorms are expected and temperatures will be around 76 degrees with an 80% chance of rain.

AccuWeather is calling for a 97% chance of rain on Race Day with a 92% probability of thunderstorms. Thunderstorms could be strong and can bring flooding downpours, hail, damaging wind gusts and tornadoes.

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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 prior to 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.

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

The NWS in Indy gives Monday a 40% chance of showers and thunderstorms. Skies could be mostly sunny with a high near 75 degrees.

The Weather Underground forecast shows scattered thunderstorms in the morning with partly cloudy skies later in the day. Chances of rain are about 40% and temperatures will be in the mid-70s.

AccuWeather says Memorial Day will see a thunderstorm in areas in the morning with mostly cloudy skies. There's a 40% chance of rain and temperatures will hit 75 degrees.

What will weather be like for Carb Day?

It's Carb Day today and NWS is predicting mostly sunny skies with a high near 84 degrees. Scattered rain and thunderstorms could roll in mainly after 8 p.m. with a chance of precipitation at 40%.

The Weather Underground forecast for today shows some clouds and possibly an isolated thunderstorm in the afternoon. Chances of rain are 30% with temperatures nearing a high of 85 degrees.

AccuWeather's forecast for Carb Day shows a 40% chance of rain. It will be very warm and humid with times of clouds and sun and a thunderstorm late this afternoon.

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What will weather be like for Legends Day?

Tomorrow is Legends Day and the NWS is currently calling for isolated showers before 2 p.m. Skies will be mostly cloudy then gradually becoming sunny with the chance of rain at only 20%. High temps will be around 82 degrees.

Weather Underground is calling for scattered thunderstorms on Saturday morning, then becoming mostly sunny later in the day. Temperatures will be near 82 degrees with a 50% chance of rain.

The AccuWeather forecast shows a 25% chance of rains for Legends Day with warm and sunny conditions and highs near 82 degrees.

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.

Nat Newell contributed to this report.

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 rain policy: Will it storm on race day? Forecast as of May 24