Spaniard Miguel Angel Jimenez flew up the leaderboard in round three as he fired a bogey-free, 7-under 65 to move into second place at 11-under-par 205.
The 65 by Jimenez was the round of the day as conditions worsened throughout the day. Rain began to fall as the leaders were finishing their front nine. Later in the round, members of the greens crew needed to squeegee water off the 18th green so the final few groups wouldn't have to putt through puddles.
The second round was completed earlier Saturday after being suspended for the night due to darkness on Friday. Heavy rain before Friday's round caused an hour delay at the start of the round. With all the rain this week, players have been able to lift-clean-and-place their golf balls.
A pair of Englishmen -- Paul Casey (69) and Simon Khan (70) -- are tied for third place at minus-8.
Jean Van de Velde, famous for his collapse at the 1999 British Open, had the second-best round of the day with a 6-under 66. He moved into a share of fifth place at 6-under-par 210, where he was joined by Nick Dougherty (74), Padraig Harrington (68) and Francois Delamontagne (71).
Howell was steady to open his round as he started with five straight pars. He dropped in a 15-foot birdie effort on the sixth at Wentworth Club's West Course to move to 12 under.
The Englishman stuck his second shot within 6 feet of the hole on the seventh and rolled that putt in for his second straight birdie. Howell was 13 under and led Dougherty by four at that point.
Howell, who had no bogeys over his previous 24 holes, three-putted for bogey on the 10th. He missed an 8-foot birdie putt at the 11th, then had no less than 35 feet for birdie over the next several holes.
The 30-year-old two-putted for par on five straight holes, including from the fringe on 16 to remain at 12 under. Howell's approach from the rough on 17 stopped 2 feet from the cup and he kicked that in for birdie and a two-stroke lead over Jimenez.
Howell, who leads the European Tour Order of Merit, got up and down for birdie at the last to stretch his lead back to three strokes.
'A 69 was a good effort in the conditions,' Howell admitted. 'Miguel has obviously played fantastically well. If I shoot 66 (on Sunday), I can take it out of most people's hands, but if Miguel plays well then I'll have to as well.
'I'm in a strong position and there's a fair chance it's between the two of us. I figured it wouldn't be as plain sailing as yesterday, and it wasn't, but I managed to stay patient.'
Howell leads after the third round for the sixth time in his European Tour career. He won three of the previous five events. Howell's best finish at this tournament came last year when he took fourth place.
Jimenez, who missed the cut in six of his previous 16 starts here, carded four birdies on his front nine. His first came at the second, then the next was at the fourth.
The Spaniard also sank birdies on seven and nine to turn at minus-8. Jimenez, whose best finish here is a tie for fourth in 1994, birdied the 11th. He converted a birdie on the par-4 16th for the second round in a row.
Jimenez got up and down for birdie from left of the green at the last to finish at 11 under.
'Today was fantastic,' Jimenez stated. 'I was very solid from tee-to-green and also very solid on the greens. My caddy did a good job of keeping everything dry.'
Soren Hansen posted a 3-under 69 to grab a share of ninth place at 5-under-par 211. He stands alongside Niclas Fasth and Robert Karlsson.
World No. 6 Ernie Els and defending champion Angel Cabrera are among eight players one stroke further back at minus-4.