By Mark Lamport-Stokes
PINEHURST North Carolina (Reuters) - U.S. Open organizers were preparing for the likelihood of late afternoon thunderstorms as the opening round of the year's second major began under cloudy skies at Pinehurst Resort on Thursday.
Little-known American Daniel Berger struck the first shot on the par-four opening hole while Swede Henrik Norlander began proceedings at the par-five 10th to launch the third U.S. Open to be played on Pinehurst's fabled No. 2 Course.
World number one Adam Scott was among the late starters, set to tee off with fellow Masters champions Bubba Watson and Charl Schwartzel from the first at 1:25 p.m. (1725 GMT) in one of the most eye-catching trios of the day.
Australian Scott, who will be seeking his second major title after clinching his first at last year's Masters, is among the favorites at Pinehurst after winning four times in his last 17 starts worldwide.
U.S. Open fans have several mouth-watering groupings to watch in the early morning, among them Swedish world number two Henrik Stenson, fifth-ranked American Matt Kuchar and England's former world number one Lee Westwood, who will start at 7.29 a.m. (1129 GMT) from the first.
Next off on that hole are three former U.S. Open champions with American Webb Simpson (2012) and Northern Irishmen Rory McIlroy (2011) and Graeme McDowell (2010) having been drawn together.
In keeping with tradition, tournament officials have placed defending U.S. Open champion Justin Rose of England in the same group as the British Open champion and the reigning U.S. Amateur winner.
Rose will tee off from the 10th hole at 7:51 a.m. along with American Phil Mickelson, a five-times major winner who is seeking his first U.S. Open crown after a record six runner-up finishes, and amateur Matthew Fitzpatrick.
In other high-profile trios, Spaniard Sergio Garcia will set off with Australian Jason Day and American Brandt Snedeker while three PGA Championship winners have been grouped together: last year's champion Jason Dufner, fellow American Keegan Bradley (2011) and Germany's Martin Kaymer (2010).
Three-times champion and world number four Tiger Woods is a notable absentee from Pinehurst as he continues to recover back surgery.
(Reporting by Mark Lamport-Stokes; Editing by Martyn Herman)