"I'll take five out of six any day of the week," Tetu said. "It's outstanding, this is the first time the cut has been in the 70s in a couple years."
Not only that, La Cañada carded the three lowest scores on the day with Morikawa, a freshman who just turned 15, shooting a three-under-par 68 for medalist honors.
"Colin played great," Tetu said. "The weather should be a little better and the greens a little smoother, but I can't imagine what he'll shoot tomorrow if the conditions are better."
Suh and Rhee shared second place with a one-over-par 72.
The rain and some slow greens proved difficult for many golfers, but Morikawa soaked it all in, as he didn't bogey a single hole.
"I like playing in the rain, it's fun," said Morikawa, who had three birdies on the day and shot a one-under-par 34 on the front nine and two-under-par 34 on the back. "It was my putting [that was working]. I hit a lot of greens but the ones I missed I had to make five footers for par and I was making all of those. The greens were tough for everybody but I was able to make those putts."
Suh, who acknowledged a friendly competition between himself and Morikawa, said he wasn't too pleased with his round.
"It was a tough day for me, it was wet and it was tough," said Suh, a sophomore. "I just kept trying and didn't give up. It could have been worse with my score, but I hung in there."
Rhee shot 36 on the front and back Wednesday and will look to shoot lower in the second round.
"Nothing was really working the best [for me] but I was always in play," Rhee said. "I just couldn't get my putter going or I would have shot a lot better, but I'm happy with my round."
Bernstein's 77 tied South Pasadena's Cole Teague and Henry Sue for sixth place. Swanson's 79 slid him just into one of the last two spots, as he tied San Marino's Kyle Ko for 11th place.
La Cañada's Andrew Park was four shots from making the cut Wednesday, as he finished with an 83.