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Structure of the lower atmosphere and boundary layer

The IFS atmospheric model has many levels in the lower atmosphere to capture the all important boundary layer but precision is difficult.  This is because there are difficulties modelling the detail of radiation exchanges at the surface the lack of uniform and widespread observations.  This affects the development and persistence of cloud, and hence also the albedo and radiative balance between surface and boundary layer air.  

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Errors in the forecast location of a front lead to large errors in the predicted airmass and surface parameters at a given location.  When a front is misplaced, dissimilar air masses either side of the front mean the structure of the atmosphere can be very different from that actually experienced.   The differences between forecast and observations can be over the whole depth of the atmosphere when a front is misplaced.  Large 2-metre temperature errors can occur.

The user should consider carefully the advance of frontal zones and use ensemble output to assess the uncertainty in timing.  Model representation of temperature and moisture structure in the lower atmosphere can be considerably different from actual observed values if a front is faster or slower than predicted.    

An example - passage of cold front in the Balkans late June 2023

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