Ya, SW @ 15 knots could = some pretty good chop, probably a metre +
Lots of time to blow across the lake and build up.
Do-able in a good size boat, kids better have sea legs or they won't have much fun, hard (for me anyway) to feel the bite with that much up-down motion.
Still 2 days for them to change the forcast as well..........
good luck if you're out, as I may be too 8D
Bogz