There's no good evidence I have seen that growth spurts happen at predictable times - none of the charts indicate this and I note Kellymom has no references.
Babies do not grow predictably. Their appetites vary and can be greater one day than the next, or one week and the next. This might coincide with a need to grow faster, or a need for more comfort, or a need to boost the milk supply.
They can happen at any time - people report them happening at x weeks or y weeks or whenever weeks, but I don't think this is a pattern that fits everyone.
Best way to 'prepare' is to accept that there will be short periods of time when your baby wants more closeness and more milk