How do Tornado's Form?

Question

What starts a tornado to turn and spin like that at such high speeds???

Answer 1

lets make this short and sweat so you dont have to read a book lol:

1. cold front and warm front meet and collide

2. the cold air sinks under the warm air thats rising, pushing it up.

3. the warm air gets cold high in the atmosphere and plummets down through the colliding fronts very quickly, causing the fronts to spin.

4. once the rotating collumn of air picks of enough speed and creates enough updraft, it picks up dirt and junk that makes the spinning coloumn of air visible

5. tornado

Answer 2

High in the atmosphere, cool air pushes against warm air. The place

where the two kinds of air meet is called a front. A front can stretch

over 100 miles (161 kilometers).

On warm days, the air near the ground is much warmer than it is at

higher elevations. Warm air rises by bubbling up from the ground, just

like the bubbles in a pot of boiling water. If the air has enough moisture

in it, the moisture condenses and forms cumulus clouds.

Sometimes, the rising air is trapped by a layer of cooler air above it. As

the day continues, the warm air builds up. If this pocket of warm air

rises quickly, it can break through the cap of cooler air like water

shooting up from a fountain and a thunderhead or cumulonimbus

(kyu-mya-lo-NIM-buhs) cloud, grows, topped by an anvil cloud. The

thunderheads most likely to cause tornadoes are those that form along

and ahead of fronts.

Strong, fast winds tend to blow along and above fronts. If slower surface

winds blow opposite to the direction of the higher winds, a vertical

wind shear forms. Vertical wind shear can cause the rising air in a

thunderhead to begin to rotate.

A supercell is a thunderstorm with a constantly rotating updraft.

Supercells are responsible for a high percentage of severe weather

events, especially tornadoes.

If the rising column of air in a thunderhead begins to rotate, it is called a

mesocyclone (mez-uh-SY-klon). In a mesocyclone, the updrafts and

down drafts are in near balance, allowing the storm to continue for

several hours.

As a mesocyclone rotates, it stretches toward warm air near the ground.

The lower part of the mesocyclone narrows. The narrower it becomes,

the faster it spins.

When this vortex dips down from the mesocyclone, it draws in warm,

moist air. The air cools as it is pulled up into the column. Tiny droplets

of water form and a whirling cloud appears. This cloud is called a

funnel cloud.

Some funnel clouds hang straight down from the storm cloud. Others

stretch sideways through the sky. A funnel cloud may dip down and then

retract into the mesocyclone, or it may touch the ground. If it touches

the ground, the funnel cloud is called a tornado.

Answer 3

Tornadoes can travel at any speeds. The average foreward motion of a tornado is between 25-35 mph, however, speeds can vary from stationary to as much as 65-70 mph! The average direction a tornado travels is from Southwest to Northeast but again tornadoes can travel in any direction.

Tornadoes are most likely to strike areas to the East of the Rocky Mountains and to the West of the Appalachians. However, tornadoes can strike anywhere in the United States and in the world (except Antarctica and North Pole).

For tornadoes to form you need warm moist air at the surface and cold dry air aloft. The warm moist air rides Northward from the Gulf of Mexico and the cool dry air comes in from Canada or from air traveling over the Rocky Mountains. You also need lots of speed shear (change of wind speeds with height) and directional shear (change in wind direction with height). You don't want wind speeds to be too strong though as this can actually kill off tornadoes b/c the updraft gets tilted too much and the storm can't grow very tall. You also need lots of instability but the amount of instability doesn't have to be as great when you are working with lots of shear.

In the Plains you want surface winds to be out of the South or the Southeast. This will bring in the warm moist air needed at the surface. Up at 925mb you want winds to be S or SE as well b/c you need warmth and moisture at this level as well. Dew points here should be above 18-20C. Winds should be between 20-40 knots here. At 850mb winds should be more from the S. This means there is slight directional shear here and there is also moisture at this level. Winds of 30-45 knots is looked for. Dew points here should be greater than 12C-14C. At 700mb you want winds to be more from the WSW. Winds here should be right around 40-45 knots. This would be winds coming more of land than from the Gulf which means the air here would be much drier. Dew points should be less than 5-6C and below 0C is considered significant. You want temps here to be below 8C but this is season dependent. At 500mb you would like to see temperatures below -15C but this again is season dependent. Winds here should be around 60-80 knots. On rare occasions winds at this level could be as much as 100 knots. Meteorologists refer to this as the "barb of death". Winds should be more out of the W here, even NW winds here combined with S or SE winds at the surface indicated strong directional shear. The 500mb winds are also considered the Mid level jet. At 250-300mb, where the upper level jet is located you would like winds to be at least 85-90 mph but no stronger than 135-150 knots. Winds here should be more out of the WNW. You really don't want to see NNW winds as these tend to blow the anvils to areas ahead of the storm which can decrease potential instability. If you look on a map and see a U-shaped bend in the Upper Level Jet these have been noted in some major outbreaks.

You also want high helicity values which you will have if you have strong directional shear.

You should also have very steep lapse rates. Lapse rate is defined as decrease of temperature with height. The steeper the decrease of temperature the steeper the lapse rates. This is also a factor which can strongly increase lift.

The set-ups usually are a low pressure digging in from the Southern Rockies. As the low travels over the Rockies it deepens very quickly. The low then drags a Warm Front Northward which pushes the warm moist air Northward. The low also drags a cold front South and East. This is where the warm moist air and cooler drier air meet. Along warm fronts is usually where the increased tornado threats exist as there is strong directional shear along warm fronts.

Elizabeth H,

Extremely low pressures in the middle of a tornado DOES NOT cause buildings to explode.  That is 100% complete myth.  What causes most damage to buildings is the strong winds and flying debris.  This is what causes the damages to buildings NOT the extremely low pressures.

poseidon,

That answer makes very little sense at all.  The fronts do not rotate.  I'm not sure what you mean by that anyway.  What is rotating is the storms updraft.  Strong directional shear causes horizontal rotation and when the updraft is strong enough it tilts the horizontal updraft into a vertical position.  

Your 4th point also makes no sense at all.  Your answer may be sort but it is definitely not sweet or correct.

Answer 4

Tornadoes always come from severe thunderstorms, often called super cells.    There are many factors involved in tornado formation and this is when those factors are in the extreme.   Surface heating,  low level moisture,  mid level dry infusion,  cold air aloft and very high lifted indexes.   Once a forecaster sees these situations setting up,  they analyze current and forecast data to see if they have the necessary conditions favorable for these storms.

Low pressure extremes are directly correlated to wind speed and things such as high relative vorticity values.   The forecaster will study the structures of storms as well for high winds and that is used to forecast wind speeds of thunderstorms.

Answer 5

violent storms over land, with wind speeds up to 650km/h are called tornadoes. they form when a funnel-like column of air sinks down from a cumulonimbus cloud, as warm air rises and rotates around it. a tornado's centre has extremely low air pressures. the great difference between the air pressure in buildings and the air pressure in a tornado can make buildings explode. the fierce winds have been known to lift people into the air and tear trees out of the ground.

about 500 to 600 tornadoes occur in the United States every year. they move over land between 30 and 60 km/h and leave a trail of destruction before they finally die out.

Answer 6

by funnel clouds and pressure lots of pressure from the cold and hot winds intersecting