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  Numerical weather prediction


There are several groups all working within the Numerical Weather Prediction area of the Met Office, all with the ultimate aim of improving the numerical model that is used to forecast the weather; this in turn increases the accuracy of the forecasts that are issued. The model may be improved by better numerical techniques and representation of the atmosphere, by making better use of existing observations or by developing new observation types.

Numerical modelling

Numerical modelling is the representation of the atmosphere by a computer model. By improving the model, more accurate weather forecasts can be produced. Within this area you may learn more about the numerical model, how physical processes are represented and how we produce operational weather forecasts.

More about numerical modelling

How observations are used

Observations are crucial to weather forecasting. Many thousand are received each day and these are processed, quality controlled and monitored. Within this area you may learn more about different observation types, the daily coverage and the processing that is performed before they are used. Another aspect is rerunning forecasts to determine what effect particular observations had.

More about how observations are used

Data analysis and assimilation

After observations have been processed and quality controlled they then need to be incorporated, or assimilated, into the numerical model. In doing this very important process, we get a representation of the current state of the atmosphere, i.e. an analysis, from which a forecast is obtained.

More about data analysis and assimilation

Satellite applications

Perhaps one of the greatest developments in weather forecasting over the past 40 years has been the development of weather satellites. A satellite image of current cloud conditions is a familiar sight on TV weather forecasts but there is far more to satellite data than simply producing photographs. Here you will learn about the many ways that satellite data are used from an ever-growing range of instrumentation.

More about satellite applications

Observational based research

The observational based research is based on data from two facilities; an aircraft and a large range of surface-based instrumentation including a tethered kite balloon. Both the aircraft and the balloon are heavily equipped with instrumentation for determining standard meteorological parameters and more-specialised instrumentation for measuring turbulence, cloud, aerosol, radiation and chemistry.

More about observational based research

Atmospheric processes and parametrizations

Many of the physical processes that occur within the atmosphere are at a scale too small to be directly resolved by weather forecasting or climate models. Therefore, numerical representations of significant effects of these processes must be developed: we call these representations 'parametrizations'. In order to parametrize the processes we need to understand them. We do this by undertaking research using observations and very-high-resolution numerical models.

More about atmospheric processes and parametrizations

Ensemble forecasts

Typically, a numerical weather prediction model is only run once from a given set of initial conditions to produce a single forecast. However, despite the vast improvements in NWP models over the years, large errors may still occur even over relatively short forecast ranges. This is due to the chaotic nature of the atmosphere which means that a small error in the initial conditions may lead to a large error in the subsequent forecast, the so called 'butterfly effect'. Because we can never know the exact truth of the initial conditions, there will always be a degree of uncertainty in the resulting forecast. To combat this, an ensemble suite of forecasts may be run with each forecast having slightly different initial conditions to reflect the uncertainty. The resulting forecasts may be studied and the possible range of different scenarios evaluated. This may be used to calculate a probability for a particular forecast sequence.

More about ensemble forecasts

External collaboration

Some of the work performed is in conjunction with other meteorological services or other research institutions. Occasionally, the Met Office hosts international conferences or workshops.

More about external collaboration


Much of the work is written up in technical notes and some is published in various journals. A quarterly newsletter NWP Gazette is also produced and an annual Scientific and Technical Review is published alongside the Met Office Annual Report and Accounts.

More about publications

Numerical modelling
Satellite applications
Observational research
Atmospheric processes and parametrizations
Ensemble forecasts
External collaboration
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