I always thought...

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vespersparrow
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I always thought...

#1 Postby vespersparrow » Sun Jul 17, 2005 4:47 am

That typhoons spun in the opposite direction of canes?
So this typhoon hitting Taiwan I suppose is going in the same direction because its above the equator?
What if it decided to below the equator? Would it break up? Start spinning in the opposite direction?
I don't know that's why I'm asking. If this is a stupid question forgive me. If I don't know something then I ask.
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#2 Postby wxwatcher91 » Sun Jul 17, 2005 5:55 am

it is impossible for a hurricane to cross the equator. lows spin counter-clockwise in the Northern Hemisphere and clockise in the southern...

if a low ever crossed the equator it would break up into just come unorganized convection...
also this is where sometimes the higher in latitude (northern Hemisphere) means the stronger storm because there is more potential spin as you go further north (again in the Northern Hemisphere)
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#3 Postby WeatherEmperor » Sun Jul 17, 2005 1:14 pm

I think they should just call these things Hurricanes worldwide. My cousin who is older then I am thought that a Typhoon was a big tidal wave that only hits Japan.......

<RICKY>
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#4 Postby Brent » Sun Jul 17, 2005 1:19 pm

Only in the Southern Hemisphere do lows(hurricanes, non-tropical, whatever) spend clockwise.
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Mac

#5 Postby Mac » Sun Jul 17, 2005 1:21 pm

Brent wrote:Only in the Southern Hemisphere do lows(hurricanes, non-tropical, whatever) spend clockwise.


My wife can spend clockwise in both hemispheres. :roll:
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#6 Postby FritzPaul » Sun Jul 17, 2005 1:35 pm

It's caused by CE:

Coriolis effect: The acceleration that a body experiences when it moves across the surface of a rotating body. The acceleration results in a westward deflection of projectiles and currents of air or water when they move toward the Earth's equator and a eastward deflection when they move away from the equator.
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#7 Postby Gorky » Sun Jul 17, 2005 1:41 pm

Theoretically it is possible for a cyclone to cross and survive for a while, at least at the lower lattitudes, as the coriolis effect is non existant at the equator. I know Typhoon Varmei came within 100 miles of the equator and had a part of its ciruclation in the southern hemisphere with no ill effect. I believe Cyclone Agni in the Indian ocean last year crossed over a few times during it's organisation phase before becoming a tropical storm at 0.4N.
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#8 Postby StormsAhead » Sun Jul 17, 2005 1:46 pm

It's a good question. All tropical cyclones north of the equator, whether they are in the West Pacific, East Pacific, or Atlantic, spin the same way: counter-clockwise. All tropical cyclones in the southern hemisphere spin the opposite way, clockwise.

It is theoretically possible that a tropical cyclone could move across the equator. However, the coriolis force, which is the force that results from the rotation of the Earth and gives tropical cyclones their "spin", does not exist at the equator. As the theoretical cyclone moves farther into the "wrong" hemisphere, the coriolis force would work against the cyclone, and make it so much weaker that it was eventually destroyed.

That said, all tropical cyclones need the coriolis force to form, which is weak to nonexistant very near the equator. That is why they rarely form in very low latitudes (less than 5 degrees away from the equator), and also why it is incredibly rare to have an equator-crossing. However, there were several tropical cyclones in the Indian and West Pacific Oceans that formed within 3 degrees of the equator, and one of these may have actually crossed into the southern hemisphere for a short time. The Atlantic Ocean is different, because few tropical cyclones develop even south of 10 degrees north. The reason is debatable, but it is certainly not because of the coriolis force.
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#9 Postby TampaFl » Sun Jul 17, 2005 2:43 pm

Mac wrote:
Brent wrote:Only in the Southern Hemisphere do lows(hurricanes, non-tropical, whatever) spend clockwise.


My wife can spend clockwise in both hemispheres. :roll:



:lol: :lol: :lol:
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#10 Postby Hurricaneman » Sun Jul 17, 2005 2:45 pm

Usually doesnt happen, but can if the system reoganizes in the other hemisphere
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#11 Postby Aslkahuna » Sun Jul 17, 2005 3:02 pm

The operative mechanism for generating spin in low latitudes in the Pacific
and Indian Ocean Tropics is horizontal cyclonic shear generated in the Monsoon Trough which is a Low Pressure trough that migrates north and south of the Equator into the Summer Hemisphere. The trough separates monsoon westerlies on the equatorward side from the SE Trades in Southern Hemisphere on the Poleward side and from the NE Monsoon flow in the Northern Hemisphere (during the Winter) and Northern Trades (Spring). If the flow on one side (or both) becomes strong enough, then a spin up can occur in low latitudes. In the case of Vamei, the initial impetus was a NE Monsoon surge in the SCS while for other systems it has been a MJO westerly wind burst. This monsoon trough configuration is absent in most of the Atlantic.

Steve
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#12 Postby vespersparrow » Sun Jul 17, 2005 6:04 pm

:eek:

WOW!
I didn't know all this stuff!
I am wondering now why they don't teach a basic weather course or something that deals with the forces of nature in school? And I'm not talking about how thunderstorms are formed and what types of clouds exist either...
I never even heard of the coriolis force. No idea that it can stop storms and I can't imagine how else it plays into things.
Good time as any to learn.
Thanks for your replies.

Coriolis force example: Pretty kool. Quick time:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/gifs/coriolis.mov

And this is pretty cool for tracking older storms:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/hurtrack/index.html
Last edited by vespersparrow on Sun Jul 17, 2005 6:23 pm, edited 2 times in total.
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#13 Postby FritzPaul » Sun Jul 17, 2005 6:07 pm

Technically, it's the C. Effect... the force is ficticious.
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