Art is concerned with bringing something into existence. To think by art is to investigate how to generate something which may or may not exist. Art is concerned with production, not with action. One doesn't deliberate about things which are unchanging or which are not in one's power to do. Therefore prudence can't be scientific knowledge or an art.
Prudence is a disposition with true reason and ability for actions concerning human goods.
Prudence is the virtue of that part of the soul which can form opinions. Scientific knowledge is universal and necessary and what is scientifically known is demonstrable, while art and prudence are changing. Wisdom is the most accurate of all the sciences. The wise man must know both what follows from the principles but also possess truth about the principles. For prudence, particulars are more important than universals because prudence is related to action.