Friday's second round of the US PGA Championship is set to be an endurance test for players and supporters alike with torrential spells of rain forecast throughout the day at Valhalla GC in Louisville in Kentucky.

The first stoppage in play came Torrential after just 20 minutes in the second round.

Play had got under way on schedule at 7:30am (12.30pm Irish time), but the first group of joint leader Ryan Palmer, Ireland's Shane Lowry and Bob Sowards were still on the first green when it was called off.

Lowry was facing a 10 foot par putt on the first hole as he looked to continue his good form that saw him card an opening three-under-par 68.

When play got underway again, it was decided to resume play and not restart the second round again as only two groups had teed off. Lowry would miss his par putt to open with a bogey five and drop back to two under.

The forecast for the rest of the day was also not promising, with Tiger Woods predicting on Thursday that, as one of the later starters, he might not complete his second round until Saturday.

Palmer shared the lead with compatriot Kevin Chappell and England's Lee Westwood on six under par, with world number one Rory McIlroy a shot behind alongside Henrik Stenson, Chris Wood, Edoardo Molinari and Jim Furyk.

Woods, who had declared himself fit just days after withdrawing from the final round of the WGC-Bridgestone Invitational with more back problems, had struggled to an opening 74 on a day when 53 players broke par.