HELENA — In the wake of a passing cold front, expect significantly cooler weather on Monday. Lower elevations will top out in the mid-60s to lower 70s before rebounding into the mid-to-upper 70s Tuesday. Northwest flow aloft settles in by mid-week as an upper-level ridge builds across the Western U.S. and drifts eastward into our area. This setup will driver a gradual warm-up, pushing temperatures back above normal for the second half of the week. With moisture remaining scarce, rain chances stay very low, and any showers that manage to form will be light.