The annual Great South Bay Music Festival kicked off Thursday night in Patchogue.

Ticket holders lined up early to be the first ones in Shorefront Park, as musicians tuned their instruments to prepare for the first night of the four-day music fest.

MORE: Great South Bay Music Festival - What you need to know 

Suffolk police stationed several officers from every precinct to help protect visitors. The heat is something Suffolk County Police Chief Stuart Cameron says people should take into consideration this weekend.

"There's a potential for heat-related injuries so people need to drink plenty of water, have plenty of sunscreen. But there is a robust medical plan to deal with any medical emergencies," he says.

Dozens of bands are performing this weekend in addition to some of the main musical acts. The headliner for Thursday evening was Long Island band "Taking Back Sunday."

Concert-goers will be allowed to bring in one bottle of water or an empty bottle to refill at water fountains due to the expected heat wave this weekend.