Scott Parel took advantage of ideal scoring conditions Thursday morning to shoot a 4-under 66 and take the first-round lead in the weather-delayed Senior PGA Championship.

The gusting afternoon wind, which buffeted flags and shook hospitality tents across Oak Hill Country Club's East Course, hadn't yet fully arrived when Parel closed with birdies on the par-4 17th and 18th. Retief Goosen, Marco Dawson and Ken Tanigawa were a stroke back.

The round was completed just before 9 p.m., about a half-hour after the sun set, and 14 hours after the first group teed off. The long day was the result of late-morning thunderstorms that caused a delay of 2 hours, 15 minutes.

Retief Goosen flips his club after coming up short trying to hit onto the 18th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Retief Goosen flips his club after coming up short trying to hit onto the 18th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Parel also eagled the par-5 fourth, dropped a stroke on the par-4 seventh and birdied the par-5 13th.

Jesper Parnevik, Jeff Maggert and Darren Clarke shot 69s on the 6,800-yard course that changed in complexion with the dramatic shifts in weather that rolled through suburban Rochester.

The day began with temperatures in the mid-60s and hardly a whiff of a breeze. Though rain softened the usually fast greens in the afternoon, players faced 15 to 25 mph wind, with gusts up to 40. That played havoc on the narrow course with tiny greens and placed a premium on avoiding the rough.

Retief Goosen hits from the 10th tee during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Retief Goosen hits from the 10th tee during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Of the 15 players who finished under par, 12 came from the morning groups and just three from the afternoon.

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Ken Tanigawa chips onto the 15th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Ken Tanigawa chips onto the 15th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Ken Tanigawa catches the ball tossed by his caddie on the 13th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)

Ken Tanigawa catches the ball tossed by his caddie on the 13th green during the first round of the Senior PGA Championship golf tournament Thursday, May 23, 2019, at Oak Hill in Rochester, N.Y. (Jamie GermanoDemocrat & Chronicle via AP)