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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  But modelling the structure of the lowest, near surface, layers is very important for analysis (and forecasting), especially for cold temperatures at 2m.  The detailed structure of the temperature in these lowest layers can be particularly difficult to define where there are low level inversions or over complex orographic areas.  Wind shear and mixing processes at lower levels can also have an impact.

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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Fig9.1-4: Vertical profile showing differences structure of the airmass at Bucaresti.  The T+72 forecast for Bucaresti (red) showed no cloud, temperature 29°C, and Sw'ly low-level winds.  The radio sonde data showed thick cloud layers, temperature 19°C, and NE'ly low level winds.