How do the tornadoes form?

Answer 1

You

need warm, moist air from the Gulf of Mexico and cool, dry air from Canada.

When these two air masses meet, they create instability in the atmosphere.

Answer 2

Meteorologists still do not know exactly how tornadoes form, or why. But many facts are known.

Tornado Formation

Tornadoes almost always form in strong thunderstorms which develop along what is called a "dry line." A dry line is a boundary between warm, moist air and cooler, drier air which tries to slip over it. This causes a tremendous instability in the atmosphere, as warm air rises, and cooler air wants to sink. As the warmer, more humid air surges upward through the cooler air mass, water vapor condenses, causing huge cumulonimbus clouds.

The condensation of the water vapor also generates more (latent) heat, which causes the warm air, already rising, to rise even faster. In large cumulonimbus clouds, often over five miles high, there can be winds of over 70 miles per hour -- going straight up. But, as these streams of air go up, other streams of cooler air must come down. As these downward winds reach the earth, straight-line winds can go just as fast as the upward streams of air. You may have noticed in a thunderstorm that the first winds you feel are quite cool.

Meteorologists believe that where the upward and downward flow of winds meet, a horizontal (flat) area of spinning winds form, or a vortex lying sideways, so to speak. This is called horizontal vorticity. This process is greatly enhanced by strong wind shear, in which the speed or direction of the wind changes with altitude.Below this horizontal vortex, in certain places of the storm, the upward push of the warmer air is stronger, tending to "tilt" the vortex. As this process continues, they believe, the vortex is gradually changed from horizontal to vertical (up-and-down), and the storm may start rotating. .

As the vortex changes its orientation, it begins to act as a special kind of conduit for warm and cold air. Cold air descends, in the rotating winds that can be seen. But within the ring of rotating winds is an area of extreme low pressure; once again, caused by rising warm air, in an upward flow of tremendous speed. The rotation is especially strong in an updraft called a mesocyclone. If the storm intensifies rapidly enough, a relatively warm downdraft called a rear-flank downdraft or RFD can wrap around the bottom part of the mesocyclone. This can then tighten and intensify its rotation and bring it down to the ground to produce a tornado

The general principle can sometimes be seen in a draining sink. If you drain a sink with very still water, sometimes it just drains; nothing special happens. But if you give the water a little extra motion, you will see a spinning "funnel" form, directly above the sink drain. The mechanics are pretty much the same. Water is heavier than air. The air in the drain pipes wants to rise out, and the water wants to sink. The vortex that forms lets this happen faster.

More information

What is not known about how tornadoes form is why some giant thunderstorms produce tornadoes, and others, seemingly having the same characteristics, don't. Weather scientists are still studying what the differences may be, and trying to find a more exact understanding of how tornadoes form.

It is known that a dry line moves, generally, from the northwest toward the southeast. The warm air is usually moving from the southwest toward the northeast. It would be like two arrows crossing each other at right angles, with the "cold air" arrow on top and the "warm air" arrow on bottom. Meteorologists theorize that this crossing pattern adds to the development of a tornado, determining the direction of rotation (counterclockwise in the Northern Hemisphere), and determining where in a storm a tornado is most likely to form (the southeastern quadrant). Doppler radar has been very successful at predicting areas of likely tornadoes in storms, as a tornado will generally have a "signature" pattern on radar, resembling a sort of curlicue.

Scientists look at what does and doesn't happen in a storm, to try to understand more about why tornadoes form. It has been observed that there is not usually any rain near a tornado, although there may be heavy hail near one. It's also been noticed that there is heavier lightning around tornadoes. Some theorize that electrical charges may aid in the formation of a tornado, while others believe a tornado is the reason for the increased electrical charge. Some have theorized that even truck traffic on a fast highway can contribute to tornado formation, when the conditions are right, as a truck leaves a vortex of air behind it as it passes.

While no one yet knows exactly why a tornado forms, knowledge is growing every year. It is known what conditions have to be present, and it's likely that most of the current theories are pretty close to the truth. But dedicated scientists want to know more, and there are numerous scientific projects underway to try to understand tornadoes better, to aid in predicting them and saving lives.

Meteorologists and other scientists, as of 2009, still do not know exactly how tornadoes form, or why. But some facts are known.

Answer 3

The conditions that lead to the formation of tornadoes are most often met in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada. This area, dubbed "tornado alley," extends roughly from the Rocky Mountains to the Appalachians, and from Iowa and Nebraska to the Gulf of Mexico. Tornadoes can also occur elsewhere, though, including all U.S. states, Europe, Asia, and Australia.

Answer 4

Thunderstorms can form in a few ways, but simply put what happens is warm moist air, which is lighter than cool or dry air. As the air rises it cools, but the surrounding air gets colder as well so it keeps rising. Eventually the moisture in it condenses forming clouds and eventually rain. The storm continues to grow upwards, eventually reaching such a height that the top part is made of ice crystals, which produces electrical charges to produce the thunder and lightning. The rising air can occur spontaneously but is usually triggered when the warm, moist air mass collides with a cooler, drier one.

How tornadoes form is not fully understood, but this is the best explanation so far: First, a condition called wind shear, in which the speed or direction of the wind changes with altitude. If the shear is strong enough it can essentially tilt a thunderstorm, this separates the updraft and downdraft of the thunderstorm, preventing them from interfering with one another. This allows the storm to become stronger and last longer.

Additionally, if the wind shear is strong enough it can start the air rolling in what is called horizontal vorticity. This horizontal vorticity can then be turned vertical by a thunderstorm's updraft. When this happens, the thunderstorm may start rotating. The rotation is especially strong in an updraft called a mesocyclone. If the storm intensifies rapidly enough, a relatively warm downdraft called a rear-flank downdraft or RFD can wrap around the bottom part of the mesocyclone. This can then tighten and intensify its rotation and bring it down to the ground to produce a tornado.

Answer 5

Tornadoes form from thunder clouds that are recently pasing the town.

Answer 6

You

need warm, moist air from the Gulf of Mexico and cool, dry air from Canada.

When these two air masses meet, they create instability in the atmosphere.