Friday's action was washed out completely and the completion of the second round was pushed to Sunday morning, when plenty of golf was played. The final round is scheduled for Monday (Live on TGC at 12:30 p.m. ET), making this the second straight Monday finish on the PGA Tour following last week's Houston Open.
Ogilvie was four shots off the pace to start the third round at English Turn and he rocketed out of the gate with four birdies over his first nine holes to make the turn at 15 under.
At the par-4 13th, Ogilvie knocked his approach inside 7 feet and converted the birdie putt to take the lead outright at minus-16.
Ogilvie, whose best finish on the PGA Tour this season was a tie for 19th at last week's Houston Open, continued to plug along down the stretch with some remarkable shots under increasingly breezy conditions.
He found a fairway bunker off the tee at the par-5 15th and hardly advanced his ball out of the sand.
Ogilvie, who is seeking his maiden PGA Tour title, remained determined and blasted his third shot within 13 feet of the hole.
The 30-year-old ran home the birdie try on his way to a bogey-free round and a two-shot edge heading into Monday.
'I'm playing very well,' said Ogilvie. 'If it's blowing like this tomorrow, which I hope it will, it should be pretty good for me.'
Mickelson played some spectacular golf of his own that featured a chip-in birdie at the par-4 fifth. He added a birdie at the seventh but found the water en route to a bogey at the ninth.
The left-hander played his third to 5 feet for a birdie at the 11th and ran off back-to-back birdies starting at the par-4 14th to move within one of the lead.
Mickelson closed with a bogey at the last, however, to join Howell in a share of second after a round of 69.
'I'm certainly very pleased to be in the final-round pairing,' said Mickelson. 'I played very well at Augusta and had a great time afterwards and wasn't quite sure how things would go after having a couple weeks off.'
Howell held the lead briefly Sunday afternoon after a pair of front-nine birdies lifted him to 16 under.
The 24-year-old soon found trouble with bogeys at the 10th and 14th to fall off the top of the leaderboard.
Howell recovered at the 15th and hit his approach to the par-5 over the water protecting the putting surface. His ball stopped just off the green and Howell chipped to three feet for birdie to remain within two of Ogilvie at 15- under-par 201 after a round of 71.
'The way I played the first three days here, I'm just fine,' said Howell.
Justin Rose fired a 65 to move into contention at 14-under-par 202 along with Hidemichi Tanaka.
Vijay Singh, who won last Monday at the Houston Open, was one shot further back in a tie for sixth. He was joined by Matt Kuchar, K.J. Choi, Paul Azinger, Guy Boros and Brian Bateman at 13-under-par 203.
Danny Ellis, who held the 36-hole lead, struggled to a round of 82 to finish 12 shots back at 5-under-par 211.