OAKMONT, PA - JUNE 16: A weather warning sign is seen on a leaderboard during the first round of the U.S. Open at Oakmont Country Club on June 16, 2016 in Oakmont, Pennsylvania. (Photo by Ross Kinnaird/Getty Images)

OAKMONT, PA - JUNE 16: A weather warning sign is seen on a leaderboard during the first round of the U.S. Open at Oakmont Country Club on June 16, 2016 in Oakmont, Pennsylvania. (Photo by Ross Kinnaird/Getty Images)

OAKMONT, PA - JUNE 16: A weather warning sign is seen on a leaderboard during the first round of the U.S. Open at Oakmont Country Club on June 16, 2016 in Oakmont, Pennsylvania. (Photo by Andrew Redington/Getty Images)

OAKMONT, PA - JUNE 16: A weather warning sign is seen on a leaderboard during the first round of the U.S. Open at Oakmont Country Club on June 16, 2016 in Oakmont, Pennsylvania. (Photo by Ross Kinnaird/Getty Images)

OAKMONT, PA - JUNE 16: A weather warning sign is seen on a leaderboard during the first round of the U.S. Open at Oakmont Country Club on June 16, 2016 in Oakmont, Pennsylvania. (Photo by Rob Carr/Getty Images)

A couple walks on rainy weather under an umbrella, in Potsdam, near Berlin, on June 14, 2016. / AFP PHOTO / dpa / Ralf Hirschberger / Germany OUTRALF HIRSCHBERGER/AFP/Getty Images

A participant prospects gold nuggets from a bucket of sand during the International Championships in Gold Panning in Zlotoryja, Poland on May 28, 2016. Every year, with the arrival of warm weather, gold diggers from around the globe converge on the Kaczawa river in Poland's gold rush capital Zlotoryja to try their luck at panning. / AFP PHOTO / PIOTR HAWALEJPIOTR HAWALEJ/AFP/Getty Images

Participants prospect gold nuggets from a bucket of sand during the International Championships in Gold Panning in Zlotoryja, Poland on May 28, 2016. Every year, with the arrival of warm weather, gold diggers from around the globe converge on the Kaczawa river in Poland's gold rush capital Zlotoryja to try their luck at panning. / AFP PHOTO / PIOTR HAWALEJPIOTR HAWALEJ/AFP/Getty Images