And, after trying a few things, I am still not sure precisely how, as my efforts did not duplicate the effect, but here's a great thing about ceramics: everything you try will do something, and sometimes the somethings are as interesting as what you started out to do.
In this case, I centered a hump of clay as if I were going to make a plate. I used about 4 lbs, which is a lot of clay for what turned out to be a small plate, but I knew I would be cutting a lot of it away.
I used a single wire separated out from a length of steel cable, which you can buy at the hardware store to cut the hump, which was about an inch high, in half. I peeled off the top half and set it aside.
Then I used a wooden rib to bend the sides upward into a plate shape.
This effect, while nice, was not quite what I was looking for, as it created more of a pie-plate shape, with a flat bottom, than a bowl. The undulations were also smaller and closer together, but that's due to the wire used. A stretched spring might give a deeper, wider wave.
So, next effort: I used my regular cut off wire on an oblong ball of clay, moving the wire in an undulating motion, and then stretched the resulting slab.
This seemed closer to the surface of the original. After stretching and the addition of handles, my result looked like this.
This technique was less successful when I tried to cut round or square slabs - the wire met more resistance and there was an exaggerated difference between the depth of the wave on the sides vs the middle.
If I had to bet, I'd wager that Adam Pauleck used a stretched spring to make a an original, which he then cast into a hump mold, and then threw a foot onto each bowl.