Update copy of 9 Physical Considerations when Interpreting Model Output

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 and 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 assessment by forecasters to establish the representativeness of output against reality, and forecasters need also to understand the derivation of products and their possible consequent shortcomings.

There are (and probably always will be) some problems with NWP modeling including the IFS.   IFS output is constantly monitored for bias or inconsistency between forecast and observed values and 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.  It should be noted that those issues that have been marked as resolved (indicated by 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 and so 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.