Lesson Objectives

List some of the tools that meteorologists use to collection weather data.Describe exactly how these tools are supplied to collect weather data from many geographic locations and also many altitudes.Discuss the role of satellites and computers in contemporary weather forecasting.Describe how meteorologists develop accurate weather forecasts.

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Weather forecast are better than they ever before have been. According to the civilization Meteorological organization (WMO), a 5-day weather projection today is as trustworthy as a 2-day projection was 20 years ago! This is because forecasters now use advanced technologies to gather weather data, in addition to the world most an effective computers. Together, the data and computers produce complicated models that more accurately stand for the problems of the atmosphere. These models have the right to be programmed come predict how the atmosphere and the weather will change. Despite these advances, weather forecasts are still often incorrect. Weather is extremely difficult to predict since it is a complex and chaotic system.

Collecting Weather Data

To make a weather forecast, the conditions of the setting must be well-known for the location and also for the neighboring area. Temperature, waiting pressure, and other attributes of the setting must be measured and the data collected.


Thermometers measure temperature. In an old-style mercury thermometer, mercury is put in a long, an extremely narrow tube with a bulb. Since mercury is temperature sensitive, it increases when temperatures are high and contracts when they room low. A scale on the exterior of the thermometer matches up with the air temperature.

Some contemporary thermometers use a coiled strip written of 2 kinds the metal, every of i beg your pardon conducts warm differently. Together the temperature rises and falls, the coil unfolds or curls increase tighter. Other modern thermometers measure infrared radiation or electric resistance. Modern thermometers usually produce digital data that have the right to be fed straight into a computer.


Meteorologists usage barometers to measure up air press (Figure below). A barometer may contain water, air, or mercury, but like thermometers, barometers room now mostly digital.

Barometers use mercury columns to measure up air pressure.

A readjust in barometric pressure indicates that a change in weather is coming. If air push rises, a high pressure cell is on the way and clear skies have the right to be expected. If press falls, a low push cell is coming and will likely carry storm clouds. Barometric push data over a larger area can be used to identify pressure systems, fronts, and other weather systems.

Weather Stations

Weather stations save some kind of thermometer and barometer. Other instruments measure different features of the environment such together wind speed, wind direction, humidity, and also amount that precipitation. These instruments are placed in various places so the they can inspect the atmospheric features of that place (Figure below).

A land-based weather station. Weather station are located on land, the surface of the sea, and in orbit all around the world.

According to the WMO, weather info is collected from 15 satellites, 100 stationary buoys, 600 drifting buoys, 3,000 aircraft, 7,300 ships, and some 10,000 land-based stations.


Radiosondes measure atmospheric characteristics, such together temperature, pressure, and humidity as they move through the air (Figure below). Radiosondes in trip can it is in tracked to achieve wind speed and direction. Radiosondes use a radio to communicate the data they collect to a computer.

A weather balloon through a radiosonde in ~ it. The radiosonde is the bottom piece and also the parachute that will carry it to the floor is above it.

Radiosondes are launched from around 800 sites roughly the world twice everyday to administer a profile of the atmosphere. Radiosondes deserve to be dropped native a balloon or airplane to make measurements as they fall. This is done to screen storms, because that example, due to the fact that they are dangerous areas for airplanes come fly.


Radar represents Radio Detection and Ranging (Figure below). A transmitter sends out radio waves the bounce off the nearest object and then return to a receiver. Weather radar deserve to sense many characteristics of precipitation: its location, motion, intensity, and the likelihood that future precipitation. Doppler radar can likewise track how fast the precipitation falls. Radar can outline the structure of a storm and also can be used to estimate its possible effects.

Radar see of a line of thunderstorms.


Weather satellites have actually been increasingly crucial sources the weather data due to the fact that the an initial one was released in 1952. Weather satellites are the best means to monitor huge scale systems, such as storms. Satellites space able come record permanent changes, such as the amount of ice cover over the Arctic ocean in September every year.

Weather satellites may observe all energy from every wavelengths in the electromagnetic spectrum. Visible light photos record storms, clouds, fires, and also smog. Infrared pictures record clouds, water and land temperatures, and features of the ocean, such as s currents (Figure below).

Infrared data superimposed on a satellite image shows rainfall patterns in Hurricane Ernesto in 2006.

An online guide to weather forecasting native the college of Illinois is discovered here: http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/fcst/home.rxml.

Numerical Weather Prediction

The many accurate weather forecasts are made by progressed computers, with analysis and interpretation included by skilled meteorologists. These computer systems have up-to-date mathematics models that deserve to use much more data and also make many an ext calculations than would ever be possible by scientists working with just maps and calculators. Meteorologists have the right to use these results to offer much much more accurate weather forecasts and also climate predictions.

In number Weather prediction (NWP), atmospheric data from plenty of sources are plugged into supercomputers running complicated mathematical models (Figure below). The models then calculation what will occur over time at various altitudes for a grid of evenly spaced locations. The network points space usually between 10 and also 200 kilometers apart. Using the outcomes calculated through the model, the program tasks weather additional into the future. The then uses these results to task the weather still further into the future, as far as the meteorologists want to go. As soon as a forecast is made, that is broadcast by satellites to an ext than 1,000 sites roughly the world.

A weather forecast using number weather prediction.

NWP to produce the many accurate weather forecasts, yet as anyone knows, also the best forecasts room not constantly right.

Weather prediction is extremely an important for reducing property damage and even fatalities. If the proposed track of a hurricane have the right to be predicted, civilization can shot to secure your property and then evacuate (Figure below).

By predicting Hurricane Rita’s path, that is most likely that lives were saved.

Weather Maps

Weather maps simply and graphically depict meteorological problems in the atmosphere. Weather maps may display screen only one feature of the setting or lot of features. They deserve to depict information from computer models or from human being observations.

On a weather map, crucial meteorological problems are plotted for each weather station. Meteorologists use many different symbols as a quick and easy way to display screen information on the map (Figure below).

Explanation of some signs that may appear on a weather map.

Once problems have been plotted, point out of same value deserve to be linked by isolines. Weather maps can have many types of connecting lines. Because that example:

Lines of same temperature are referred to as isotherms. Isotherms display temperature gradients and can indicate the place of a front. In regards to precipitation, what does the 0°C (32°F) isotherm show?

An computer animation on how to contour isotherms is viewed here: Contouring isotherms https://courseware.e-education.psu.edu/public/meteo/meteo101demo/Examples/Shockwave/contouring0203.dcr.

Isotachs room lines of consistent wind speed. Whereby the minimum values happen high in the atmosphere, tropical cyclones may develop. The highest possible wind speeds deserve to be offered to situate the jet stream.

Surface weather analysis maps room weather maps that only show conditions on the soil (Figure below).

An online guide around to just how to read weather maps indigenous the university of Illinois is uncovered here: http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/maps/home.rxml.

More about remote sensing that weather is questioned in this online guide: http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/rs/home.rxml.

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Lesson Summary

Weather forecasts are more accurate than ever before before. Enlarge instruments and data collection methods, such as radiosondes and also weather balloons, space still used.Satellites and computers develop much much more detailed and accurate forecasts.Forecasts are regularly wrong, specifically those the predict the weather for several days.

Review Questions

What types of instruments would you mean to find at a weather station and also what do these tools measure?How does a thermometer work?How might a barometer at a solitary weather terminal predict an pull close storm?Why are weather balloons essential for weather prediction? What information do they give that no obtainable in other ways?How does radar work, and what is its value in weather prediction?Imagine the your teacher asks you come predict what the weather will be prefer tomorrow. You deserve to go external or usage a telephone, but can’t usage a TV or computer. What method will friend use?Same as over only now you have accessibility to electronics but not weather forecasts. You deserve to look in ~ weather maps and radar images however not look at interpretations make by a meteorologist. What technique will friend use?No rain is in the forecast, however it’s putting outside. How can the NWP weather forecast have missed this weather event?What go it median to say the weather is a chaotic system? how does this impact the ability to suspect the weather?

Further analysis / Supplemental Links

Points come Consider

With so much advanced technology available, what is the duty of meteorologists in producing accurate weather forecasts?With so lot advanced modern technology available, why space weather forecast so often wrong?What breakthroughs do friend think will certainly be important for meteorologists to create accurate weather prediction one- come two-weeks in breakthrough of a significant weather event?