As a cold air mass advances and a warm air mass retreats, the colder, denser air forces the warmer, lighter air to ascend either along or just ahead of the cold front. Uplift of warm air triggers cloud development and sometimes showery precipitation. The uplift can be so vigorous that thunderstorms develop. The band of clouds and precipitation associated with a cold front is ______ than that associated with a warm front. a.narrower b.wider
Eventually the cold front catches up and merges with the warm front, forming an occluded front. At this stage in the life cycle of an extratropical cyclone, the storm often weakens as the central air pressure ______, and the front reaches occlusion.
a.falls
b.rises