HALF MOON BAY — Two dozen of the world’s bravest athletes will venture into the roiling green sea off Pillar Point on Friday in the hope of conquering, and surviving, the massive waves at Mavericks.

After hesitating early Wednesday, organizers of the Mavericks Invitational pulled the trigger around 1 p.m., calling the contest for Friday morning, when a swell generated by a storm in the Pacific Ocean will smack into the coast, generating waves that are 30-40 feet or higher.

The conditions Friday should be ideal, said lead organizer and Mavericks pioneer Jeff Clark — light winds blowing out from the shore and waves the size of apartment buildings. Computer models Wednesday morning had predicted southerly winds, which would have rendered Friday’s waves unrideable. But by the early afternoon, he said, the models shifted.

“It looks like we’re going to have an amazing contest,” said Clark. “We should see sets over 40 feet.”

Still, local atmospheric conditions are tricky to predict, and there remains some concern that south winds could emerge, according to Mark Sponsler, lead forecaster for competition. But as of Thursday morning he was optimistic that the winds will be calm and the ocean will be “glassy.”

“Everyone’s pretty much breathing a sigh of relief,” he said.

The waves at Mavericks break roughly 100 yards from shore, and the beach and bluffs at Pillar Point are no longer open to the public on contest day for environmental and safety reasons. But for those who want to get as close to the action as possible, Mavericks organizers will put on a festival at Pillar Point Harbor with food, live music and big screens carrying the contest. The contest will also make its debut on national television, with the finals airing around 1:30 p.m. on the Universal Sports Network.

For the 24 competitors invited to Mavericks, word of the approaching swell stirred up a mix of fear and excitement that is unique to big-wave surfing. Nearly half the Mavericks field lives in the Bay Area, and several of them surfed the break on Tuesday, some wiping out badly.

Grant Washburn, a Mavericks veteran and three-time finalist, said Tuesday’s waves were the biggest of the season. Friday’s will likely be bigger. He anticipates “challenging and dangerous” conditions. Contestants will have to be careful not to bite off more than they can chew.

“This is not about money and winning — this is about surviving,” said Washburn. “There’s no amount of money that will make you run onto a highway and get hit by a truck.”

Santa Cruz surfer Peter Mel, who won last year’s contest, tweeted that the swell will be “very impressive and scary big.” Tyler Fox, a competitor from Aptos, said he expects waves that are “pretty thick and pretty darned heavy” when he paddles out Friday morning.

“You want to stay really focused, but also try to have fun,” Fox said. “You’ve got to keep a smile on your face even if you’re scared (out of your mind).”

Even nonsurfers should be careful Friday if they head to Bay Area beaches, said Clark. The National Weather Service will have a high-surf advisory in effect from Thursday morning through Friday night.

“If you come to the shore on Friday no matter where you are, be careful,” he said. “It will be very dangerous.”

Contact Aaron Kinney at 650-34-4357 or akinney@bayareanewsgroup.com. Follow him at Twitter.com/kinneytimes.