Until the advent of the computer and modern technologically advanced equipment, weather forecasting was accomplished by the interpretation of data from traditional instruments. Nowadays, the prediction of weather is a complex science that uses a extraordinarily large amount of computer data to arrive at an assessment.
The barometer is still the workhorse of weather gathering and forecasting systems. This centuries-old instrument measures air pressure at ground level in numerous locations. This information is then correlated into weather maps, on which areas of equal barometric pressure are connected by lines called isobars.
Other instruments developed mainly in the last 500 years can be still be used by a trained meteorologist to make a weather forecast . These instruments include the anemometer (wind speed), thermometer (air temperature), rain gauge (to measure rainfall), weather vane (wind direction) and hygrometer (relative humidity). Modern equivalents of these instruments provide contemporary data.
Computers, which have been aiding meteorologists since the 1960s, can help in determining the weather forecast. Nowadays a computer can handle so much data that the machine is capable of creating a very accurate model of a short-term weather situation.
Weather balloons are launched daily carrying instruments that are used to collect data from the upper atmosphere, which is then transmitted by radio signal back to the Earth's surface.
Since 1960, weather satellites have been launched into space to send back aerial photographs depicting cloud movements, water vapor concentrations and surface conditions.
Weather aircraft are stationed around the United States to make specific, data-gathering flights into various developing weather situations. These aircraft have been made famous by their flights into ocean-born hurricanes, but they fly into many weather conditions besides tropical cyclones.
