A weather warning sign hangs as spectators watch the first round of the U.S. Open golf tournament at Merion Golf Club. (Charlie Riedel/AP)

The U.S. Open was less than two hours old when officials made what could be the first of many decisions to stop play because of strong storms Thursday morning at Merion Golf Club.

When play was suspended at 8:36 a.m., six of the 26 groups from the morning wave had yet to tee off. Because the storms involved lightning, players were required to mark their balls where they were and evacuate immediately – even before rain had started. They did not have the option to complete the holes they were playing.

U.S. Golf Association officials announced that the first round will resume at 12:10 p.m., leaving the delay at 3 hours, 34 minutes.

Ian Poulter, who birdied his first three holes – Nos. 11, 12 and 13 – holds the early lead at 3 under, a stroke ahead of four players. The first group of the day, which teed off at 6:45 a.m. from No. 1, had completed only six holes.

Storms are projected in the Philadelphia suburbs through noon, when there may be an opportunity to resume play. Rain has saturated Merion’s East Course over the past week; the course took on at least six inches, and players practiced in fits and starts through the weekend, and have been preparing for a soggy playing surface all week.

The delay means the first round almost certainly won’t be completed Thursday, and the USGA will have to scramble to get the tournament back on schedule. The afternoon wave of players – half of the field of 156 – was scheduled to begin play at 12:30 p.m. The marquee group of the first two rounds – Tiger Woods, Rory McIlroy and Adam Scott – was scheduled to start from No. 1 at 1:14 p.m. All of those times will be pushed back.

Even in the early going, and even with Poulter’s bold start, Merion showed its teeth, even at 6,996 yards – the shortest course in a major championship since 2004. Keegan Bradley, the former PGA Championship winner playing in a group with Phil Mickelsonand Steve Stricker, hit his drive on the 430-yard 16th just into the right rough, which is at least four inches deep. He hacked from there into the middle of a shrub that sat in a bunker below the green, had to take an unplayable lie, and appeared on his way to double bogey when play was halted.

In 2009, the USGA faced something of a doomsday scenario at Bethpage State Park’s Black Course on Long Island. No round finished completion on its scheduled day, and Lucas Glover won the championship on Monday afternoon.