3 questions heading into Friday at The Open Championship

Jordan Spieth, Brooks Koepka, and Matt Kuchar set the pace Thursday at Royal Birkdale Golf Club, posting 5-under-par 65s to sit atop the leaderboard at The Open Championship.

Here are three questions heading into the second round of the season's third major championship:

Who survives the weather?

The 156-player field enjoyed the favorable conditions Thursday at Royal Birkdale, but that won't be the case on Day 2 of The Open. Friday's forecast is likely going to be the worst of the week for the players, with winds expected to hit 35 mph and heavy rain throughout the day.

"That combination of wind and rain is not always that pleasant to be out in," said Henrik Stenson told reporters after a first-round 69. "So we've got to keep our heads down tomorrow."

Can Koepka keep it going?

The reigning U.S. Open champion showed no signs of rust in the first round of The Open, posting a 5-under-par 65 to share the lead with Jordan Spieth and Matt Kuchar. Koepka is 31-under par since last year's PGA Championship at Baltusrol, and has carded seven straight rounds of par or better in the majors. The 27-year-old American's long game wasn't crisp on Day 1, but his short game was deadly, needing just 21 putts.

Did Rory McIlroy find something?

It looked like the world No. 4 would have another weekend off after bogeying five of his first six holes to sit in a tie for 121st place. McIlroy eventually settled down, though, shedding four strokes over his last 12 holes to climb back into contention.

"I really didn't find the middle of the club face until the seventh tee," McIlroy said. "I hit a good shot on seven - even though it didn't hit the green, it was a better strike, it was a better golf shot. I took a little bit from that, and from there it was ... I'll go to bed tonight just thinking of those last 12 holes."

(Photos courtesy: Action Images)