Ch. 15 Questions for Thought

Why are North Atlantic hurricanes more apt to form in October than in May?

In May the surface ocean water in the subtropics is still relatively cool from the winter. In October the water is still warm from the summer.

Would it be possible for a hurricane to form in the tropical North Atlantic or North Pacific during December? Explain.

It would be possible if the water temperature remained warm enough. During most years the water is too cold to generate hurricanes and so the hurricane season officially ends on November 30. However, during a strong El Niño event, the water may remain warm into December. As an example, Hurricane Winnie formed over the tropical eastern Pacific on December 4, 1983.

Suppose this year five tropical storms develop into full fledged hurricanes over the North Atlantic Ocean. Would the name of the third hurricane begin with the letter C? Explain.

It would not necessarily begin with the letter C because several tropical storms may have formed but not developed into full-blown hurricanes before this.

Give several reasons how a hurricane that once began to weaken can strengthen.

Possible reasons include: the hurricane can pass over an area of warm surface ocean water, it can move away from the equator where the Coriolis force is stronger, it can experience decreasing levels of vertical wind shear, the trade wind inversion can weaken, upper-level divergence can increase.

Occasionally when a hurricane moves inland, it will encounter a mountain range. Describe what will happen when this occurs. What will happen to the hurricane's intensity? What will cause the most damage? Why?

The hurricane's dissipation will be somewhat slowed if it encounters a mountain range after making landfall, because orographic lifting will provide some vertical motions to the air. The most damage is likely to be from flooding and flash flooding resulting from heavy rains.

Explain why the ocean surface water temperature is usually cooler after the passage of a hurricane.

The rapid rate of evaporation cools the water.

Would the winds of a hurricane decrease more quickly as the storm moves over cooler water or over warmer land? Explain.

The winds would decrease more quickly when the hurricane moves over land. The storm would be deprived of its primary source of energy (latent heat of condensation) and friction with the surface would disrupt its circulation and slow its winds.

You are in Darwin, Australia, and a hurricane approaches from the north. Where would the highest storm surge be, to the east or west? Explain.

To the east. Winds circulate clockwise around tropical cyclones in the Southern Hemisphere, so the onshore winds (and the storm surge) will arrive to the east of Darwin.

Suppose, in the North Atlantic, an eastward-moving ocean vessel is directly in the path of a westward-moving hurricane. What would be the ship's wisest course- to veer to the north of the storm or to the south of the storm? Explain.

Veering to the south of the storm. The hurricane's strongest winds would be found in its northern sector.

Suppose a tropical storm in the Gulf of Mexico moves westward across Central America and out over the Pacific. If the storm maintains tropical storm strength the entire time, do you feel it should be given a new name over the Pacific? Explain your reasoning.

Yes. The tropical storm should be given a new name because it is now an eastern Pacific storm, which are named according to a different list than north Atlantic storms.