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Extreme Weather:
Tornadoes
FACT or FICTION
The internal winds of a tornado can hit almost 500 mph (805 k/h).
Most reach about 200mph.
The only continent that hasn't experienced a tornado is Australia.
Antarctica is the only continent that has never experienced a tornado. About 2,000 tornadoes touch down in the United States every year.
Only about 1,000 tornadoes hit every year
http://www.youtube.com/watch?v=43VoMesUd2Q
http://videos.howstuffworks.com/discovery/46742­tornado­rampage­tornado­in­the­road­
video.htm
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Thunderstorms:
Thunderstorms result from the rapid upward movement of warm, moist air. They can occur inside warm,
moist air masses and at fronts. As the warm, moist air moves upward, it cools, condenses, and forms cumulonimbus clouds that can reach heights of over 20 km. As the rising air reaches its dew point, water droplets and ice form and begin falling the long distance through the clouds towards the Earth's surface. As the droplets fall, they collide with other droplets and become larger. The falling droplets create a downdraft of air that spreads out at the Earth's surface and causes strong winds associated with thunderstorms
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WHY DO POLAR REGIONS HAVE A HIGHER RELATIVE HUMIDITY??
Answer
In the polar regions, temperatures are low, dew point temperatures are also low, and relative humidity is high. The air in polar regions is usually around 80% saturated. Even though the water vapor content of the air is low, the water vapor capacity is low as well. Saturation occurs in air that holds very little water vapor even when the air is relatively dry. As a consequence, the relative humidity is higher at polar regions
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Hurricanes
1985 – 2005 environment Canada
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Hurricanes/Typhoons/Cyclones:
These are some of the basic forces at work when a low­pressure center forms in the atmosphere ­­ a center that may turn into what people in the North Atlantic, North Pacific and Caribbean regions call a __________________________. Hurricanes can only form in extensive ocean areas with a surface temperature _______________ than 26.5 deg C. This is because the warm ocean water provides sensible heat and water vapour that fuels the intense convection of a hurricane, and assists the conversion of a cold­core tropical depression to a warm­core cyclone.
The air closest to us is the warmest and as the atmosphere is mostly heated by the ­­­­­
___________ and the ________________, not by the sun. To understand this principle, think of a person frying an egg on the sidewalk on a hot, sunny day. The heat absorbed by the pavement actually fries the egg, not the heat coming down from the sun. When air heats up, its molecules move ____________ and ____________________apart, making it ______________________ dense. This air then rises to higher altitudes where air molecules are less compressed by gravity. When warm, low­pressure air rises, cool, high­pressure air seizes the opportunity to move in underneath it. What else is happening?
The warm water is one of the most important contributors to hurricane formation because it acts as the "fuel" for the storm. As water vapour rises, it _________________ and once saturation is reached, the water vapour _________________________ into liquid water that we see as clouds, in this case storm clouds and precipitation. During the process of condensation, heat is released, known as _____________________________. This warms the atmosphere, making the air lighter and causing it to rise further. As this occurs, more warm humid air from the surface of the ocean must move in to take its place. This inflowing air will begin to rotate under the influence of the Coriolis Force, or the ­­­­­­­­­­­
________________________. As the pressure drops in the center of the storm, signifying strengthening, the ­­­­­­­­­­­­­­­­­­_________________________________ becomes stronger. This pressure gradient is directly related to wind speed and the stronger the pressure gradient, the faster the wind speed.
And the cycle continues, drawing more, warm, moist air into the developing storm and moving heat from the surface to the atmosphere. This exchange of heat creates a pattern of win­d that circulates around a center, like water going down a drain.
Latent heat of condensation Coriolos Affect
Greater
Sea Condenses Faster
Land Less Hurricane
Pressure gradient force Further
Cools
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