What does Romeo predict and what literary element does this demonstrate?

In an example of foreshadowing, Romeo predicts his own death in Act I, Scene 4. Foreshadowing is the use of clues to hint at events that will occur later in the plot. After Mercutio's fantastical Queen Mab speech, Romeo expresses his fears at the end of the scene in an aside. An aside is a theatrical term for words spoken by a character either to the audience or to another character, that are not intended to be heard by other characters on stage. Romeo believes that fate is guiding him and that attendance at Capulet's party will begin a series of events which will ultimately lead to his death. Here, and later in the play, he invokes the idea of the stars. In the Prologue, Shakespeare calls Romeo and Juliet, "star-crossed lovers." This reference is to astrology and horoscopes which purport to be able to predict a person's fate by examining the positions of the planets and other celestial objects at a particular time, usually at birth. Romeo alludes to the stars in his short aside:

I fear too early, for my mind misgives
Some consequence yet hanging in the stars
Shall bitterly begin his fearful date
With this night’s revels, and expire the term
Of a despisèd life closed in my breast
By some vile forfeit of untimely death.
But he that hath the steerage of my course
Direct my sail. On, lusty gentlemen.

As his words indicate, Romeo is unable to avoid fate's temptation and, even though he realizes he may be walking into disaster, he goes along to the party with the other Montague men. At the party, of course, he meets Juliet and his fate is sealed.