Forecasting future weather starts by knowing what the weather is doing right now – everywhere in the world!
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We can easily look out our window and see what the weather is like right now. But what if we need to know what the weather will be like in the future, say tomorrow or next week? Maybe your family are planning to have a picnic next weekend, but you won’t be able to have it outside if it’s going to rain. How can your family plan ahead? This is where meteorologists rely on lots of cool technology to predict the future.
Forecasting future weather starts by knowing what the weather is doing right now – everywhere in the world! Since we can’t be everywhere at once, we rely on weather observations that are recorded by weather stations all around the globe, usually at least once per hour, every hour, 365 days a year.
Even right here in New Zealand we have hundreds of weather stations taking weather observations every day. As you can see in the pictures below, some of these stations are in pretty amazing locations!
Let’s take a quick look at some of the most important tools attached to these weather stations.
Thermometer: This tells us what the temperature is throughout the day.
Anemometer: This instrument usually sits on top of a giant pole about 10 metres above the ground and records the wind speed.
Rain gauge: This one’s pretty easy – it tells us how much rain has fallen today.
Barometer: Remember learning about high and low pressure? Well a barometer can actually “feel” how much pressure is in the atmosphere and how quickly it’s going up or down.
Here are a few other important tools not found on weather stations that provide meteorologists with vital data:
Doppler radar: This looks a bit like a giant satellite dish and sends out pulses of energy that bounce off rain droplets and return to the radar site. This lets us see where rain is falling, even if it’s hundreds of kilometres away from us.
Weather balloon: It is also important to know what’s happening high in the atmosphere. Weather balloons are released from the ground and can fly higher than airplanes. They have small instruments attached to them that record things like temperature, wind speed, and wind direction as they climb. This data is sent back to the ground using a simple radio.
Watch this video to understand more about weather balloons!
Weather satellite: Meteorologists use satellites in outer space to see things like cloud formations and tropical cyclones that might be located far from land. Some satellites are so high up that they can see almost half of the earth all at once.
Buoys: Ocean buoys provide similar information to weather stations, like temperature and wind speed, but also useful information like the temperature of the ocean water.
Airplanes: That’s right—almost every airplane records weather information as it flies, and some of this data is used to help us make better weather forecasts.
We’ve collected all this weather data from around the world – now what happens?
With so much data being collected every day, it’s impossible for humans to analyse it all and make a forecast within a reasonable amount of time. So the data goes into powerful supercomputers that speed up the process. These supercomputers are as big as an entire room, and more powerful than 10,000 desktop computers.
The supercomputers run all the data through incredibly complex math equations that determine how the earth’s atmosphere moves, and after a few hours of calculations we get the supercomputer’s best guess about what the weather will be like over the next several days.
However, at this point human meteorologists step in. While the forecast produced by the supercomputer is usually pretty good, the meteorologist has years of experience studying and forecasting the weather and can make the forecast even better.
The meteorologist will turn the weather forecast data into the colourful graphics and moving maps that you see on television or the internet.
One question meteorologists get asked a lot is, “How accurate is a weather forecast?” Forecasts are getting better and better as computing power improves. 50 or 60 years ago, it was impressive just to be able to forecast the next day’s weather accurately, never mind several days into the future. Nowadays, forecasts three to five days in the future are usually very accurate, and forecasts seven days out can still give a general idea of what’s to come. After seven days, the accuracy of the forecast usually decreases quite a bit.
This activity comes from https://nz.education.com/science-fair/article/DIY-rain-gauge/
(The quiz works best on kahoot, but if you prefer a text version, you can download it as a PDF here).