Brad Bryant, who has already won twice this season, carded a 3-under 69 to move into second place at 10-under-par 134.
Defending champion Dana Quigley and Gary McCord each posted rounds of 4-under 68 to move into a share of third place at minus-9. They were joined there by Keith Fergus, who fired a 7-under 65 in round two. Bob Gilder and Lonnie Nielsen are one stroke further back at 8-under-par 136.
Edwards started his second round on the back nine of the Nicklaus Golf Club at LionsGate and opened with a two-putt birdie on the par-5 10th. Two holes later, Edwards chipped his third to 3 feet to set up his second birdie.
The 50-year-old, who has won four times on the PGA TOUR, parred his next 11 holes. On the par-5 sixth, Edwards drained a 20-foot birdie effort to move to 12 under.
Edwards however stumbled to a bogey at the next to slip back to 11 under. At the ninth, his last, Edwards ran in a 10-footer for par to remain one clear of Bryant.
'I played pretty well, but it was difficult with the wind,' Edwards said. 'You've got to grind it out when its this windy. We're two-thirds of the way through, I hope I stay in the hunt the last nine holes and have a chance in the end.'
Bryant quickly jumped to 9 under as he eagled the 10th, his first, from 12 feet out. He two-putted for birdie on the 12th before parring the next six holes.
The 51-year-old Bryant got to 11 under as he dropped in a birdie putt on the par-4 first. He faltered to bogeys on the third and fifth to slide back to 9 under. Bryant got one stroke back with a birdie on the par-5 sixth.
'That was a pretty decent round. The course played a little tougher today,' said Bryant. 'I've never been this good of a player. I'm much better putter now.'
R.W. Eaks posted a 4-under 68 Saturday to move into a tie for seventh at 7-under-par 137. He stands alongside Des Smyth (72), Tom Jenkins (72) and Tim Simpson (70).
Local favorite Tom Watson leads a group of six players one stroke further back at minus-6.