Considerations when interpreting model output

IFS forecasts are true to the physical representation and parameterisation of the atmosphere and its processes within the IFS programs and systems.  However, they are dependent upon good reliable data.  Also they can deviate from reality through amplification of errors on different scales as the forecast progresses.  Capturing possible error-growth scenarios is a strength of the ensemble approach and uncertainty can be assessed by using ensemble products.  However, the more detailed structure of the atmosphere, particularly in the lower layers, requires forecasters to consider how representative of output is in reality.  Forecasters need to understand the derivation of products and their possible consequent shortcomings.

There are (and probably always will be) some problems with NWP modelling including the IFS.   IFS output is constantly monitored for bias or inconsistency between forecast and observed values.  A list of inconsistencies is maintained and dynamically updated with a view to rectification of the problems.  Keep up-to-date with known IFS forecasting issues.  Note, those issues that have been marked as resolved (grey text in the link) will still be relevant when inspecting historical data.

This section gives pointers towards features which can have an impact on output.  These can help users to modify and improve forecasts for issue to customers.  The importance of critical assessment of output by human forecasters cannot be overstated.