By Mark Lamport-Stokes
ARDMORE, Pennsylvania (Reuters) - U.S. Open organizers were preparing for severe thunderstorms and high winds for Thursday's opening round at Merion, which has already been saturated by more than six inches of rain since Friday.
Though the iconic par-70 East Course drains very well, extra care has been taken over the location of pin positions on greens more susceptible to puddling while the safety of players and spectators has been paramount in contingency plans.
"It could be anything from a quarter or half-an-inch up to two or three inches (of rain)," United States Golf Association executive director Mike Davis told reporters on Wednesday about the weather expected for Thursday afternoon and evening.
"It really depends on what hits us or how lucky or unlucky we are. But there could be some really high winds with us, potentially damaging winds, even some hail.
"That's kind of the worst case scenario. It's going to be probably mid-afternoon or later, too, so I think tomorrow morning we're looking okay."
The National Weather Service is tracking a derecho, a widespread and long-lived windstorm that is associated with a fast-moving band of severe thunderstorms, that is expected to hit the Philadelphia area on Thursday afternoon.
Davis said he had great faith in the state-of-the-art lightning detection devices and radar available to the on-site meteorologist at this week's U.S. Open, being held in suburban Philadelphia.
"And not only are those devices here on-site at Merion, but they're actually spread out around Philadelphia," said Davis.
"Our meteorologist can look at what's happening west of here, north of here, south, east, and it really does give a great picture. We're quite comfortable with it."
Asked what precautions were being taken both on and off the course, Davis replied: "Outside the ropes ... we have done a lot to try to make muddy areas more passable, so that will continue.
"In some places we've even had to put down rock roads, certainly in parking lots where we're not on (tar) macadam.
"Inside the ropes it really is just trying to anticipate what you might get. If that means rebuilding bunkers, if that means pumping, that all goes into it."
The biggest concern for organizers after Monday's torrential downpours at Merion was the green and greenside bunker at the 11th hole, the lowest point on the course, and Davis said pin positions for the opening round had been meticulously planned.
"Our hole locations for round one, we thought through every single one of them and said, 'Not only do we need to be mindful of the wind we might get, but we need to be mindful of where we might get puddling'," Davis added.
"But this course drains beautifully. And the putting greens ... they drain as well as any putting greens I've seen. They (the greenkeeping staff) are as equipped as possibly they could get for that rain event."
(Reporting by Mark Lamport-Stokes; Editing by Julian Linden)