Craig Barlow tallied 10 points in the modified Stableford scoring system to finish alone in second place with 17 points. Mark Brooks had the best score of the second round with 14 points and owns third with a total of 15 points.
This format rewards aggressive play as golfers receive two points for a birdie, five points for an eagle and eight points for a double-eagle. One point is deducted for a bogey and three points for a double-bogey or worse, with a par receiving no points.
British Open champion Ernie Els is alone in fourth place with 14 points.
For the second consecutive day, swirling winds played havoc with the players at Castle Pines Golf Club and scores were higher than previous years. The 36- hole cut fell at minus-two points, the highest at The International since 1993, the first year that scores from the first three rounds carried over to the final round.
'I think it's playing as hard as it's ever played,' said Lowery, whose last victory on tour was the 2000 Southern Farm Bureau Classic. 'The wind blew pretty much all day. The greens are firmer and faster than they've been the past few years.'
Lowery seemed to handle the blustery conditions Friday. His first birdie came at the fifth hole, when he drained a 12-footer, and he made it three in a row with a three-footer at six and a 35-footer at No. 7.
The 41-year-old closed his front nine with an 18-foot birdie putt at the ninth to make the turn with eight points.
Lowery got off to a shaky start on the back nine when he saved par from 70 yards out at the 10th, but he found no such luck at 11. His second shot at the par-3 went over the green and Lowery actually holed a clutch six-foot bogey putt to limit the damage to a loss of only one point.
Lowery rebounded at the 12th when he drained a 12-foot birdie putt and picked up back-to-back birdies after a 15-footer at the 13th. He landed in a greenside bunker at the par-5 17th, but blasted out to three feet and tapped in the birdie putt for two more points.
'The course played tough. It was really windy and tough to pull the right club,' said Lowery, who finished third behind David Toms and Phil Mickelson in last year's PGA Championship. 'I shot 6-under today in some difficult conditions. If I keep playing like this, I've got a good chance to win.'
Lowery earned his first PGA Tour title at The International in 1994 and took the course knowledge with him into this year's event.
'It's always good to come back to a golf course you've won on,' he said. 'I remember that I made eagles on 14 and 17. I eagled 17 (Thursday), so that hole has been pretty good to me.'
Barlow opened on the back nine at Castle Pines and tallied six points after a lip-out bogey at the par-4 fifth. He immediately responded with a tough, downhill 20-footer for birdie at the sixth and, after hitting a pitching wedge at the 185-yard, par-3 seventh, he ran home a 12-footer to close the round with 10 points.
'Fortunately I made a lot of birdies,' said Barlow, who is 199th on the money list. 'I mean I normally make a lot of birdies and unfortunately I make bogeys. But in this format you don't get punished as much by having birdies and bogeys.'
Overnight leader Steve Pate picked up zero points Friday but is tied for fifth with 11 points. He was joined by Billy Mayfair, Jay Haas and Geoff Ogilvy 10 points behind Lowery.
Several of golf's top stars struggled mightily in the windy, difficult conditions. David Duval's woes continued Friday as he finished with minus-14 points to finish 130th out of the 136 players who completed two rounds. Duval's two-day total was minus-16 points.
Mickelson fared even worse. The lefthander racked up four double-bogeys, six bogeys and one birdie Friday for minus-16 points and a two-day total of minus-18 points. Mickelson, a two-time International champion, tied for 133rd and missed the 36-hole cut for the second time in 10 trips to Castle Pines.