Carlota Ciganda shot a six-under 66 to share the lead with fellow home-town favourite Sarah Schmelzel and South Korean Hyo Joo Kim.
Two days of ideal conditions and low scoring gave way to gusty wind that had balls oscillating on the greens at Seville Golf and Country Club on Saturday.
In-form Perth ace Hannah Green had the overnight lead at 14 under, but quickly fell back as the blustery conditions made pulling the right club and even putting difficult.
The leaders found a way to navigate the tough conditions.
An Arizona State alum from Spain, Ciganda had two eagles before the wind started sending plumes of dust across the course, posting an early 15-under 201 in her bid to win for the first time in eight years.
Schmelzel, also an Arizona resident who grew up in the area, shot 70 in her bid to win on the LPGA Tour for the first time.
Kim had three birdies in her first four holes and closed with 14 straight pars to shoot 69.
Yuka Saso overcame a four-putt double bogey on No.15 with two birdies in her final three holes to shoot 69 and reach 14 under. She's tied with Maja Stark, who had one of the free bogey-free rounds with a 66.
Top-ranked Nelly Korda stayed steady to shoot 69 and is two strokes back in her bid to become the first LPGA player to win three straight starts since Ariya Jutanugarn in 2016.
The American chipped in on the island par-3 17th for a second straight birdie to join 10 players at 13 under.
"It was brutal, played like a completely different golf course," Korda said.
"I think the wind started picking up at noon and just got progressively windier and windier as the day went on.
"It's very open out here, so the ball gets hit really hard with this weather. Happy to get in at 3 under."
Lexi Thompson is in that group at 13 under as well, two-putting for birdie on the par-5 18th for a 69 that put her in contention to win for the first time in five years.
Ciganda was among the players who took advantage of an earlier tee time, eagling the par-5 fifth hole and adding another on the short par-4 16th to climb quickly up the leaderboard.
Playing in front of numerous family and friends in the afternoon, Schmelzel rolled in a 50-foot birdie putt on No. 10, but gave it back on the next hole by missing a short par putt.
She rolled in a birdie on the par-4 13th and got up and down for another on the short par-4 16th to reach 15 under.
WA rookie Hira Naveed fired a brilliant 65 to join Gabriela Ruffels (70) as the leading Australians in a tie for 16th at 12 under and still well in the mix only three shots off the lead.
Green had 11 birdies - second-most in LPGA Tour history - in a second-round 61 that gave her the overnight lead by one.
She had a hard time following it up in the wind, shooting a 75 that drop to 11 under.
With AAP
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