Florida - Tiger Woods's bid to regain the world No 1 ranking with an eighth Bay Hill title was put on hold when a severe thunder storm forced the final round finish to be pushed to Monday.
Woods and playing partner Rickie Fowler had just completed the second hole when the horns blew to stop play. Woods's birdie at the par-three second put him 12-under for the tournament and stretched his lead to three strokes over Fowler, Keegan Bradley, Ken Duke and John Huh.
Woods won his seventh Arnold Palmer Invitational title here last year. A record eighth triumph in the event would see him supplant Northern Ireland's Rory McIlroy atop the world rankings.
The 14-time major champion has spent a record 623 weeks on top of the world.
But he has not paced the rankings since October of 2010 after injuries and an infamous sex scandal saw him tumble from the top 50.
Sunday's storm swept across the course in dramatic fashion, with gusting winds toppling a television tower behind the 10th green.
NBC broadcaster Dan Hicks tweeted that five camera towers were blown over. Spectators were evacuated from the course and reporters from the media tent as the storm spawned a tornado warning in the area and briefly cut power in the clubhouse.
After play had been stopped for about an hour and a half, officials announced that the round would resume at 10 am (14:00 GMT) on Monday.
"Golf course is gone, bunkers are gone. We're going to need time for the course to drain," said PGA Tour vice president of rules and competition Mark Russell.
Woods took a two-shot lead into the final round after a six-under par 66 on Saturday.
Woods, who has won 50 times in 54 tries when holding the lead entering the final round, seeks his 77th career PGA triumph -- five shy of matching Sam Snead's all-time record - in his final tuneup event for next month's Masters.
Woods has won five titles in the past 12 months, a run that began at Palmer's event last year when he won his first PGA title since the sex scandal. This year, Woods has already collected triumphs at Torrey Pines and Doral.
With a win, Woods would become the first player to win the same PGA event eight times.
He is already the first to win eight times at the same course after seven PGA titles and the 2008 US Open crown at Torrey Pines.
Thirty-three players completed their rounds on Sunday. They included Masters champion Bubba Watson, who carded a five-under 67 for a four-under total of 284.
Sergio Garcia said he wouldn't be back on Monday, withdrawing after play was suspended.
Before the storm hit Garcia enlivened the day by playing a shot out of a tree near the fairway of the par-four 10th.
Garcia was five-over for the day after a quadruple-bogey, a double-bogey and a bogey along with two birdies in 12 holes.