Having a clear overview of the weather forecast is one of the most important parts of keeping an airport running. Understanding the current conditions helps pilots to land planes at airports safely and on schedule. Learn more about what a weather forecast is and how forecasters devise their forecasts below
It is important for many industries – and the general public – to have an idea of weather events in their local area and other parts of the world. Having knowledge of these things ahead of time can enable you to plan effectively and be safe in the event of an extreme weather event. Weather forecasts can help in predicting the weather and they are a crucial part of planning for many people.
But how is a weather forecast put together? And why are they sometimes not accurate
What is a weather forecast?
A weather forecast is a scientific prediction of the climate, atmosphere and weather for an impending period. This includes establishing factors such as wind speed, cloud cover, temperature and the likelihood of rainfall. Depending on the nature of the forecast itself, there are several different levels of locational precision that forecasters use. A weather forecast for an airport is known as a terminal aerodrome forecast, or a TAF, and covers approximately a five-mile area around the airport itself.
How is a weather forecast made
Creating a weather forecast is a complex and scientific process relying on a range of factors. The steps in creating a weather forecast include:
- Establishing starting conditions
The first step in the process involves establishing the starting conditions for the weather. This includes having a range of measurement stations in many different locations assessing quantitative factors such as the temperature, precipitation, humidity and wind direction and speed. Having a comprehensive picture of the weather is known as the “observation” stage of the process and provides a basis for the rest of the forecast. Observations take place on the surface, from a selection of weather balloons and from weather radars. The greater detail available at this stage of the process, the more accurate the forecast is later on.
- Using algorithms
Following the observational stage, the process is relatively automated. At this point, the forecasting team inserts their observational data into supercomputer models that examine a selection of historical data and surrounding information, ultimately establishing where the weather will move and how it will evolve throughout a set period. Airports tend to use 24-30 hour periods for their forecasts, as this minimises the speculation within equations and ensures as much accuracy as feasibly possible. TAF focuses on very specific areas as a means of improving precision for incoming pilots.
- Meteorological adjustment
During the final stage of the process, a meteorologist adjusts the assessment and tracks the forecast. Although forecasts do a good job of predicting the weather, unforeseen factors can arise quickly. In the event that the weather shifts away from the expected process or the algorithm’s prediction is flawed, meteorologists can step in and adjust the forecast. This means that TAF is a constantly evolving forecast providing an accurate perception of the weather in the coming hours, rather than a static prediction in line with exclusively initial data. After this, airports transmit forecasts using the TAF/METAR code, conveying all relevant information to Qatar’s arriving pilots.
How is weather forecasting done?
In order to predict the weather, meteorologists gather as much information as possible about the current weather and atmospheric conditions. They will make observations about things like temperature, pressure, wind speed and humidity, looking out across the globe and entering the data into powerful supercomputers. like the Cray XC40.
These observations are made using advanced technology, such as:
Automatic rain gauges
Weather balloons and Vaisala Radiosonde (an electronic device for measuring meteorological variables in the atmosphere
These computers process enormous amounts of data to make algorithmic predictions about what current conditions say about what might happen next with the weather. Meteorologists also monitor conditions separately to assess whether things are going as expected, and will tweak the forecast when things change.
Why aren’t weather forecasts always accurate?
The Earth’s atmosphere is not always orderly, and relatively small shifts in the ocean can have a huge impact on the behaviour of a weather system. Something that looked like it might only be minor when it reaches land could end up being a lot more severe than anticipated.
With this unpredictability in the atmosphere, things can be missed or misinterpreted. Thus, something that is forecasted to happen in a week’s time is likely to change before that day comes.
Having said that, our understanding of the atmosphere is constantly improving. Similarly, computer technology is advancing and improving, so forecasts are now able to look further into the future with greater accuracy than before. A four-day forecast today is thought to be as accurate as a one-day forecast was three decades ago.
Even when they are not entirely accurate, longer forecasts can give a good general idea of weather trends. You can get a measure of whether it is likely to be drier or wetter than average in the coming week. The computers can also model the way our climate might look in the future, and can make predictions decades in advance.
What makes some weather particularly difficult to forecast
Certain weather patterns present greater challenges for accurate forecasting than others. For example, showers are very small-scale weather features, so it is difficult to accurately predict where they will occur.
It may look to you as if a weather forecast was wrong because you didn’t see the showers they warned you about. But, in actuality, those showers ended up manifesting just a few miles down the road, perhaps in the form of a torrential thunderstorm.
What does the future of weather forecasting look like?
With the continuing evolution of computer technology, particularly relating to processing speed, it will be possible for a greater number of observations to be captured. This data will be able to be put into more complex equations, enabling the creation of more forecasts for even smaller areas.
What this should amount to is greater accuracy in weather forecasting in the future.