Indianapolis Motor Speedway is asking fans to account for the likelihood of bad weather and lightning protocols when planning their arrival at the track for today’s 108th Indianapolis 500.

“We do think we’re going to get some some sort of weather at some point in time today,” IMS President Doug Boles said on Sunday morning. “Our biggest concern in that weather is not the rain as much as it is the lightning. And our biggest concern overall is making sure that our customers here at the Speedway are safe. So we will continue to monitor that.”

The Speedway, the NTT IndyCar Series, broadcaster NBC and other stakeholders have been discussing weather contingencies over the past several days. At one point there was the possibility that the race would be moved half an hour forward for a 12:15pm green flag, however that was based on predictions that the storm would hit mid-afternoon. Updated modeling suggesting that the rain is now likely to arrive closer to noon means that an early start has been ruled out.