In order to prepare for disasters, its important to try to predict when something is going to happen. Using past information and present technology, scientists today have it pretty well figured out. There are certain routines for certain disasters. Some things we understand very well and others we're just beginning to understand.

• Prediction Today
• Warning Systems
• History
• Technology Advances
• Crawling Critters
• Local Forecasting

Prediction Today

Our lives are gradually becoming more dependent on computers, from simple presentations to high-tech calculations. Weather forecasting is also becoming dependent on computers that can quickly do the hundreds of millions of calculations needed to make an accurate 24-hour forecast. Every ten minutes, such computers take information and develop predictions for forecasters. There are four models that forecast weather. These models calculate and predict specific weather conditions at various altitudes throughout the atmosphere. At times, the results from all four computers agree, but other times the calculations turn out very different. These differences are due to the fact that the computer models base everything on mathematics, so there are limitations to their capabilities. The assumptions that are made by the computer are often not carried out by the weather.

After computers do their job, forecasters analyze the weather models and come up with their own predictions. In the United States, the National Meteorological Center issues general forecasts, and the local forecasters make more detailed readings of local conditions. Satellites also circulate the globe to provide images and information to forecasters, and weather balloons are released that transmit observations from the atmosphere. Many other instruments, such as Doppler radar, are used to help forecasters predict the weather.

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Warning Systems

There are many warning systems to warn people when a severe storm is headed their way.

• Severe-thunderstorm watch: If the conditions indicate possible severe storms, a severe-thunderstorm watch is issued for six to eight hours.
• Severe-thunderstorm warming: When severe storms are actually observed, either on the ground or by radar, a severe-thunderstorm warning is issued.
• Tornado watch: If the conditions indicate possible tornadoes, a tornado watch is issued for six to eight hours.
• Tornado warning: When tornadoes are actually observed, a tornado warning is issued.
• Flash-flood watch: Hydrologists issue this advisory for a 12- to 24-hour period if weather conditions suggest that rapid flooding may occur along streams and in low-lying areas.
• Flash-flood warning: When flooding is definitely about to occur or is spotted, a flash-flood warning is issued.

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History

Forecasting is limited because there are hundreds of miles out of view that are important to determine approaching weather. Signs, such as approaching black clouds, help to forecast the weather, but it is often not reliable or it is too late before you can read the sign. Accurate weather forecasting requites an understanding of how storms form and travel. Scientists began to understand these things during the 18th century.

On October 21, 1743, Benjamin Franklin watched a storm in Philadelphia and concluded that the storm was travelling from the same direction as the winds came from. However, this is not always true. When he found out that the storm had actually traveled the opposite direction, Franklin learned not to assume the storm traveled the same direction as the winds. This was the first development of understanding the movement of storms, but the scientists lacked the technology to warn distant people of approaching storms.

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Technology Advances

When the telegraph was invented in 1837, telegraph offices were soon established in cities and army posts all over the world. By 1850, basic information such as temperature, barometric pressure, precipitation, and wind could be sent by telegraph, allowing the information forecasters discover to be useful to other people around the world. This basic information was sent to the Smithsonian Institution in Washington, D.C., where weather maps were published.

The early forecasts of this time, called daily "probabilities," were issued by the Cincinnati Observatory. Then in the 1870s, the United States Congress funded the Weather Bureau, now the National Weather Service, to establish a national early-warning system for severe storms. Great Britain and several European nations established similar weather services at this time.

In the late 19th and early 20th centuries, the forecasting became more accurate. More reporting stations opened, and the wireless radio communication helped to spread the findings. Now, not only could other scientists get the information, but residents interested in what weather was heading their way.

The first experimental weather satellites were released in the 1960s. These satellites, with the modifications made over the years, show views of clouds and weather systems from above so forecasters can watch them form, move, evolve, and dissipate. At about the same time as the first satellites, computers helped to do calculations in a few hours that typically took days to figure out by hand. In the mid-1950s, a research group produced a simple computerized forecasting model. The first model simply forecasted changes in air pressure and airflow at about 18,000 feet (5,500 meters) above sea level. Now meteorologists use high-speed computers that gather, organize, and graphically display the weather data. Other computers analyze weather maps and generate forecasts. All this work is based on mathematical formulas, and the end product is getting more and more accurate.

Today the technology is amazing, and the results more reliable. The satellite program of today is called the Geostationary Operational Environment Satellite (GOES) program. These satellites are placed into a geosynchronous orbit, an orbit that keeps the satellite fixed 22,240 miles above one position on the earth. This allows the GOES program to continually monitor atmospheric activity. Every ten to fifteen minutes, the satellites transmit complete images of whatever part of the world they are stationed over. A sounder attached to the satellites monitors atmospheric temperature and humidity by measuring the amount of infrared radiation that reaches the spacecraft. Another important technological advance of today is radar, which stands for radio detection and ranging. This system emits a radio frequency pulse and listens for the echo off a distant object. It was originally developed for aircraft and ships, but it also helps detect and track storm activity by reflecting the radio waves off of water drops and ice particles within the storm. In the 1960s, radar was combined with computers to create Doppler radar. This system returns information on the object's location, distance, speed, and direction of travel with respect to the radar, as well as the density of the object.

There is still a long way to go to reach complete accuracy on these forecasts, and it will probably never happen. However, we are headed in the right direction. The next step is a modified fifteen-day-forecast model that will be much more accurate. Right now, we do have thirty- and ninety-day forecasts, but they only say what the temperature will be compared to normal and have to be updated about every fifteen days. Using improved technology and the power of computers, we should hopefully be able to get the power we need to predict forecasts with generated small scale weather systems.

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Crawling Critters

There are many ways to forecast, and the technology of today is keeping us comfortable. However, forecasting use to be less accurate and more of a guess. Also, some people don't have access to the high-tech tools needed in forecasting. One tool that is available is the natural tools: animals, insects, and even plants. These tools aren't always reliable, but do change with the weather. Uncomfortable situations brought by weather can be brought out by the restlessness of an animal. Below you can see some of the common forecasting techniques using animals. However, sometimes the animals can be misinterpreted, and often times not all of the same animal breed react the same. Since animals might make certain "weather" signs at any time, look for multiple clues to be sure. If many signs happen at the same time that indicate rain is on the way, it probably is.

• If ants their walls do frequent build, rain will from the clouds be spilled.
• When spiders weave their webs by noon, fine weather is coming soon.
• The gnats bite and I scratch in vain, because they know it is going to rain.
• If bees stay at home, rain will soon come; if they fly away, fine will be the day.
• Insects flying in numbers just at evening show weather changing to rain.
• Fireflies fly very low before a rain.
• When cockroaches fly, rain will drop by.
• The locust sings when it is to be hot and clear.
• A robin in a bush means rain.
• When swans fly against the wind, rain is coming.
• Swallows fly high: clear blue sky; swallows fly low: rain shall know.
• If eels are very lively, it is a sign of rain.
• If fowls roll in the sand, rain is at hand.
• Frogs croak before a rain, but in sun stay quiet again.
• If many earthworms appear, rain will follow.
• Fish bite the least, with wind in the east. (A thunder storm is approaching)
• Salt becomes damp before rain.
• When cattle lie down during a light rain, it will soon pass.
• When cattle are on hilltops, fine weather is coming.
• When cattle stand with their backs to the wind, rain is coming.
• Goats leave high ground and seek shelter before a storm.
• When pigs carry hay or straw in their mouths, there will be rain or wind.
• When the donkey blows his horn, 'tis time to house your corn.
• When a cat sneezes, it is a sign of rain.
• If flowers stay open all night, the weather will be wet the next day.
• When the leaves of trees curl during a south wind, it will rain.
• Seaweed dry, sunny sky; seaweed wet, rain you'll get.
• If watercress beds steam on a summer evening, the next day will be hot.
• When sunflowers raise their heads, it is a sign of rain.
• Pondweed sinks before a storm.

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Local Forecasting

You can try to forecast the weather yourself. Although you probably don't have the technology or background needed to get an accurate reading, you can get a rough idea of coming weather using common sense and weather patterns. The first step is to set up your own weather station, where you can record temperature, air pressure, wind direction, and simple weather factors like those. You can use our building instructions found under the "Tools" section to get you started.

Now for prediction. Collect weather maps from your newspaper for three or four days and see how the fronts and weather patterns are moving across your country. Then after about three days, try to predict the weather for the next day. Unless the pattern stalls, you should be able to forecast whether it will be good or stormy weather. Another thing to try: using your weather station, record your daily observations (using the chart below). Print several copies of the chart, or make your own. If you have access to a computer, you can enter your daily observations and compile the statistical information in graphs. Then determine what you think the forecast will be like, print it out, and give it to your friends. Or, if your school has a closed-circuit television system or public address system, ask if you can present your weather forecast each day

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