Stratiform and cirrus clouds can extend several hundred miles in advance of a surface front and foretell frontal passage several ______ in advance.

• A. hours
• B. days
• C. weeks
• D. months

Answer: (B)

The idea is recognizing how large-scale weather systems show themselves before they arrive. Stratiform and cirrus clouds are indicators of an approaching front, forming well ahead of the actual surface boundary as moisture and lift spread through the atmosphere. Because these fronts are vast and move with the jet-stream pattern, the visible signs can appear hundreds of miles in advance and the front can pass a region several days later. So the lead time you can expect from these cloud patterns is measured in days, not hours, weeks, or months.