Well, technically a "premonition" is merely a feeling and not related to Psi ability... though I'm not sure if that's what your question refers to. Premonitions could also be described as INSTINCTUAL feelings. For instance, if you were at an airport and suddenly had vague but ominous thoughts about plane crashes. You have no reason to believe YOUR flight will crash, but just feel a general sense of dread or bad vibes. Premonitions can just as easily be positive. For instance, you drive by a convenience store and get a sudden urge to purchase a lotto ticket, feeling particularly lucky at that moment.
In parapsychological terms, premonitions really aren't considered significant. However, PRECOGNITION denotes foreknowledge of future events. It comes in two forms: dreams & flashes (waking visions.) They are anything BUT vague and the seer usually envisions very specific or intricate details.
I was only 5-6 the first time I had a precognitive dream, so it's something I've experienced all my life. There used to be an international site where you report precognitive dreams or flashes and several of my reports turned out to be quite accurate (including the date, location & time of an earthquake overseas). Obviously, premonitions are much more common than true precognition, but any person can have a precognitive experience totally at random, reinforcing the idea that they stem from a very natural human ability.