Why should we study the weather?

     Weather affects our everyday lives but is really important to know for some people more than others, especially if you are a pilot, a construction worker, a fisherman, a farmer or even going on a vacation..
     

     The blanket of air around the earth is called the atmosphere. It is about 15 miles thick. All of our weather happens in the bottom layer of the atmosphere, called the troposphere, which is six to ten miles thick. Meteorology is the study of the changes in temperature, air pressure, moisture, and wind direction in the troposphere.

      In the darkest regions of deep space, the temperature is a chilly -450° Fahrenheit. Closer to our Sun, temperatures reach thousands of degrees Fahrenheit! What makes Earth's climate so moderate? Separating Earth from the extreme and inhospitable climate of space is a 500-mile-thick cocoon of gases called, you guessed it: the atmosphere!
     There's more to get familiar with in the atmosphere , and the layers of the atmosphere.

          A cloud occurs when the invisible water vapor in the air becomes visible water droplets or ice crystals. Water vapor becomes visible by cooling. That is what happens on a cold wintry afternoon when you see your breath. Warm air leaving your mouth cools and forms visible droplets.

     There are many kinds of clouds, and each one signals a different kind of weather. Cumulus are puffy mid-level white clouds made of water and ice, usually associated with fair weather. Cirrus clouds are high up in the troposphere and are wispy and thin due to the strong winds at that altitude. Though they are composed of ice, they are usually associated with pleasant weather. Stratus clouds, which form in lower parts of the troposphere, consist of water droplets and cover most of the sky with an even, gray color similar to a fog, which can signal light rain. Cumulonimbus clouds are tall, dense clouds shaped like a block or anvil. They signal thunderstorms as well as violent weather effects such as hail and lightning. Photos of types of clouds

   So what does all this mean?

     All of our weather comes from basically two things: the sun and the moisture in the air. These two work together to form clouds, to make rain and thunderstorms, and to cause winds to blow. The sun emits energy at an almost constant rate, but a region receives more heat when the sun is higher in the sky and when there are more hours of sunlight in a day. The high sun of the Tropics makes this area much warmer than the poles, and in summer the high sun and long days make the region much warmer than in winter.

     The wind blows because air has weight. Cold air weighs more than warm air, so the pressure of cold air is greater. When the sun warms the air, the air expands, gets lighter, and rises. Cooler, heavier air blows to where the warmer and lighter air was, or in other words, wind usually blows from areas of high air pressure to areas of low pressure. If the high pressure area is very close to the low pressure area, or if the pressure difference (or temperature difference) is very great, the wind can blow very fast.

     The sun is the engine that drives the motion of water in our atmosphere. This movement of water is called the water cycle, which is also known as the hydrologic cycle. It involves the continuous circulation of water in the atmosphere through evaporation, transpiration, condensation, precipitation, and runoff.
Study this diagram to help you understand the Hydrologic Cycle.

On June 22, 2003, a hailstone recovered in Aurora, NE, had a diameter of 7" (17.8 cm) and a circumference of 18 3/4" (47.6 cm). This hailstone was larger than the previous record large hailstone that fell in Coffeyville, KS, in 1970 (5.7" (14.5 cm) diameter and 17.5" (44.5 cm) circumference). However, weight, is the most important measurement. An accurate weight could not be determined for the Aurora hailstone; so the Coffeyville hailstone of 1970 remains the heaviest hailstone weighed and verified in the United States at 1.67 pounds (0.76 kg).

Hail causes $1 billion in damages to crops and property each year.
Hailstones can fall at speeds up to 120 mph (53 m/s).
The costliest United States hailstorm: Fort worth, Texas, May 5 1995. Total damage was $2 billion.

     People have been forecasting the weather for centuries. They once looked to plants and animals for hints about the weather. Before it rains, ants move to higher ground, cows lie down, pine cones open up, frogs croak more frequently, and sheep's wool uncurls. Before technology, folks also made forecasts by studying the clouds.

     You may have been raised to believe that groundhogs can predict the length and severity of winter weather. Groundhog Day, which is celebrated on February 2 in the United States, is based on ancient Celtic beliefs that if winter's midpoint was sunny and clear, winter would be long and cold. Nowadays, in the U.S., a groundhog named Punxsutawney Phil is the keystone of the celebration. If he sees his shadow, it is thought that this presages a long winter. (Unfortunately, Phil's "predictions" have been accurate only about one-third of the time.)

So with all these factors, how can we predict/forecast the weather?

     A daily weather forecast involves the work of thousands of observers and meteorologists all over the world, and the work of thousands of machines. Modern computers make forecasts more accurate than ever, and weather satellites orbiting the earth take photographs of clouds from space. Weather forecasts made for 12 and 24 hours are typically quite accurate. Forecasts made for two and three days are usually good. Beyond about five days, forecast accuracy falls off rapidly. Satellite images of the US weather...

• One inch of rain over one square mile equals to 17.4 million gallons (66 million liters) of water.
• The weight of one inch of water over one square mile equals over 145 million pounds (66 million kg).
• 145 million pounds of water is almost 73,000 tons or the weight of 241 locomotives.
  This is a lot of water held up by wind.
• Clouds are made of trillions of tiny droplets of water (or when cold enough, ice crystals)!
• There is so much water in the air that if it all fell as rain at the same time, it could fill enough buckets to reach from the earth to the sun 57 million times!
• You can tell the temperature by counting the clicks a cricket makes in 15 seconds and adding 37!

Head outside, study the weather and become a meteorologist! There is always some interesting weather to observe.