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Description:

The largest spin-up issues occurs during the first 2 hours of the forecast. It is therefore recommended to primarily use the 6 hourly analysis fields whenever this is possible. Also, it seems that three hourly values can be used without larger restriction. The spin-up problems are most pronounced during turbulent conditions, for example connected to deep low pressure systems, and should therefore be limited in space and time.

These spin-up problems are in some situations causing too high wind speeds for the 1-2 hour forecasts. This is most pronounced in the wind gust but the problem also occurs for the mean wind at 10 meter altitude. Similar problems can be seen for maximum/minimum temperature. Then in general there is a spin-up problem for precipitation. Here, it is not recommended to use the first 6 hours of the forecasts. Therefore, if a user wants to use the 24 hour accumulated precipitation it is recommended to use the 30-6 hour forecasts.