How is weather predicted

There are three important stages to a weather forecast:. In order to know what the weather will do in the future, we first need to know accurately what it is doing now. Recordings of weather variables are made 24 hours a day across the globe.

These are passed to the world's major weather forecasting centres and used in conjunction with satellite pictures to get a picture of what the atmosphere is doing now. February 15, They are very curious to know how meteorologists predict the weather, and I am happy to answer them! Thank you for your questions! Your inquiries are very similar, so I will be able to answer the three of you simultaneously. Meteorologists are able to predict the changes in weather patterns by using several different tools.

They use these tools to measure atmospheric conditions that occurred in the past and present, and they apply this information to create educated guesses about the future weather. Always remember that a weather forecast is an educated guess — meteorologists and mankind, in general cannot control the weather. The best we can do is observe past and present atmospheric patterns and data, and apply this information to what we think will happen in the future.

Meteorologists use the scientific method on a daily — and even hourly — basis! Meteorologists use many different tools for different purposes. Most people are familiar with thermometers, barometers, and anemometers for measuring temperature, air pressure, and wind speed, respectively.

Meteorologists use other tools, as well. For example, weather balloons are special balloons that have a weather pack on them that measures temperature, air pressure, wind speed, and wind direction in all the layers of the troposphere. Picture courtesy of Mike Theiss, ExtremeNature.

As forecasts improve, one question naturally arises: How much better can they get? Unfortunately, the chaotic nature of our atmosphere seriously limits our ability to model it — and therefore to predict what it will do next. In practice, this means that a single weather model run more than once with even the most subtle differences in starting conditions can produce very different predictions. Since no measurement is perfect — every observation has an associated uncertainty — these small imperfections can cause big changes in what a model predicts.

These changes get bigger and bigger the further ahead you try to predict. Because of this, the potential predictability limit of weather is about two weeks, says Henson. But we will never be able to measure everything about every point in the atmosphere all the time with ultimate precision, and our models will never be flawless. There are more ways to improve forecasts than taking better observations and improving our weather models.

Understanding how people use forecasts and warnings allows meteorologists to provide information in the most useful way.

One of the biggest challenges for meteorologists is condensing a forecast, which represents a spread of possible weather conditions to expect, into a single icon or a few sentences that appear in your weather app. Most forecasters calculate this number by multiplying their confidence that rain will occur by the area in which the rain might happen. So a 40 percent chance of rain might be a percent chance in 40 percent of your county, or, a 60 percent chance across 70 percent of your county.

So the next time you see a low chance of rain in your forecast, check the full weather report before you leave the umbrella at home. So a lot of the challenge now is, how do we get people what they need? NOAA is working with social scientists to develop forecasts that are more relevant and better targeted. This is especially important because of how the internet has changed the way people obtain and share information, Kelsch says.

For instance, when creating the official forecast, meteorologists account for uncertainties by running a model several times. Each time, the model will give a slightly different result, but most results will be very similar.

This ensemble of predictions is what becomes the official forecast. But outlying, low-probability results occur in the ensemble, too. And though forecasts have improved dramatically, meteorologists are still blamed when they are wrong. In many countries, a single public weather service is typically the only source available for forecasts, warnings and alerts. These meteorologists work for public government organizations or universities.

By contrast, the United States has strong public, private commercial and university-based weather observation and forecasting programs. In other words, the U. The NCEP runs weather models, then disseminates the results — as well as forecasts — to NWS offices, which may customize the forecasts for their region. For long-term, large area predictions, the most popular U.

The new system, called GFS-FV3, is better at modeling moisture and clouds, allowing meteorologists to forecast storms with greater accuracy than ever before.

Commercial weather providers typically have some weather modeling capabilities of their own. For example, Weather Underground refines the official forecast to a neighborhood scale by adding information from its network of over a quarter-million personal weather stations.