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Re: [Phys-l] hurricane question



On 11/08/2008 08:31 AM, Marty Weiss wrote:

Hurricanes usually begin as tropical depressions in the Atlantic off
the coast of Africa, and then work their way westward to the Caribbean
or Gulf, hitting Florida or the Gulf coast, with some heading north
toward the Carolinas or Bermuda before ending up in New England, etc.
Lately in this season, however, we have seen two hurricanes in a row
(Omar and Paloma) starting in the Caribbean as depressions, developing
quickly into category 3 storms hitting the islands from the south and
west and then heading out into the Atlantic. Why does this reverse
pattern occur?

Hurricanes are moved along by the wind, more-or-less the
way clouds are moved along by the wind.

A hurricane is basically just a big vortex. The physics
of vortices is discussed in Feynman volume II chapter 40.

Does it have anything to do with colder weather patterns
and ocean temperatures in the Atlantic?

Not so much the ocean temperature. Temperature is a scalar.
It's hard to steer anything with a scalar. The hurricane
gets its /energy/ from warm water ... but not its momentum.

The seasonal weather in the _air_ is relevant, because the
prevailing wind patterns -- like migratory birds -- tend to
"follow the sun" i.e. in the northern hemisphere they move
south for the winter.

There is a nice, long, detailed, readable discussion of climate
and weather in the Encyclopedia Britannica.