I analyze English and Finnish FRONT adpositions commonly used in SEQUENCE metaphors of time (The days ahead of Christmas are busy). A SEQUENCE metaphor represents the order of temporal entities as their different positions on a path along which they are moving, a temporally earlier entity being ‘ahead of’ a later
one, i.e. further advanced in the direction of motion. In English, the motion-related FRONT preposition ahead of is conventional in SEQUENCE metaphors, as opposed to in front of, which is used only occasionally and often results in ill-formedness (*Monday is in front of Tuesday). In Finnish, the dedicated two-mover adposition
edellä ‘ahead of [two-mover]’ is conventional in SEQUENCE metaphors, while the general FRONT adposition edessä is not. Based on an analysis of these adpositions in different scenarios of spatial motion, I argue that the adpositions common in SEQUENCE metaphors (ahead of, edellä) evoke a motion frame of reference (motion FoR). In the motion FoR, FRONT is adjacent to the direction where the moving Ground (the entity designated by the complement of the adposition) is headed. In contrast, adpositions that bear a strong association with the standard (intrinsic or relative) FoRs (in front of and edessä) are less felicitous in SEQUENCE metaphors. Together, the two languages demonstrate how a metaphorical motion scenario in a
SEQUENCE metaphor is grammatically coded as a stable, unchanging array, where both participants are steadily moving in the same direction.