The first indications a mariner will have of the approach of a warm front will be __________.

Correct Answer: Option A — high cirrus clouds gradually changing to cirrostratus and then to altostratus

Per Bowditch meteorological principles, warm front passage is first heralded by high cirrus clouds, which progressively thicken and lower into cirrostratus and altostratus as the frontal slope overrides the colder surface air.