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At Stuttgart, Budapest and Nis the lowest ~500 m is poorly represented.  Solar radiation in the atmospheric model is depleted/enhanced by the presence/absence of fog or low stratus cloud.  At Bucaresti the temperature structure of the lowest layers is modelled quite well, but the moisture structure near the subsidence inversion is not.  Differences in boundary layer moisture have a strong influence on the development of stratocumulus as surface temperatures rise during the morning. 

Consequences from an error in the forecast location of a front 

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.    

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

The cold front was associated with very thick cloud cover and patchy rain.  2m temperatures were low for this time of year under the frontal cloud, and in the post-frontal cold air temperatures were only between 13°C and 20°C.  The T+72 forecast for Bucharesti showed no cloud, temperature 29°C, and SW'ly low-level winds.  But observations showed thick cloud layers, temperature 19°C, and NE'ly low-level winds.  However, the ensemble members showed uncertainty in the position of the cold front and the spread in temperature was very large in the whole boundary layer.

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FigXXX: Errors in 2m temperature over the Balkans T+72 DT12UTC 25 June, VT 12UTC 28 June 2023.  The cold front advanced further than predicted with extensive cloud depressing temperatures ahead of the front and allowing an inflow of colder air to the rear.  Colours show where forecast temperatures are too warm (red and purple), too cold (blue).

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FigXXX: Vertical profile showing differences structure of the airmass at Bucharesti.  The T+72 forecast for Bucharesti (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.