With a 100 percent chance of rain forecast for July 4th and flash flood warnings in effect through Friday, city officials are preparing for the worst in planning for the AJC Peachtree Road Race.

Delays could force a postponement, said Atlanta Police Chief George Turner, but rain alone will not lead to the cancellation of one of the city’s signature events.

“I think right now it’s just important to know that we have plans that we can put in place,” said Tracey Russell, executive director of the Atlanta Track Club, speaking at a news conference Tuesday attended by Turner and Mayor Kasim Reed. “Right now we are looking to have a great event that might just be a little wet.”

An Event Alert System will be in place along the 6.2 mile course, which winds from Buckhead to Piedmont Park. Colored flags will communicate warnings ranging from “Low” (green) to “Extreme” (black) based on a variety of factors, including weather conditions.

“We are starting at yellow knowing there is going to be precipitation,” Russell said. A yellow flag signifies less than ideal conditions, with a black flag indicating the event has been canceled. A red flag denotes particularly dangerous conditions.

Turner said any decision to delay or cancel the race would be made in conjunction with the Atlanta Track Club after consulting with the National Weather Service and FEMA.

“Police officers don’t run from the rain,” he said.

Spectators and participants will notice increased security at this year’s race in the wake of April’s bombing at the Boston Marathon.

“My first, second and third priorities are to have everyone safe,” Reed said.

Parts of Piedmont Park, which marks the end of the 6.2 mile course, will be restricted, officials said. Spectators are discouraged from bringing backpacks, and those who do are subject to a search.

Participants are encouraged to wear blue and yellow to honor the victims of the Boston bombing. A moment of silence in their memory will take place prior to the start of the race.

—Staff writer Bryan Cronan contributed to this report.