DESS: Why is the forecast 2-6 times higher sometimes - how is solar forecast working?

Last day then a pause for min a week.
Today it should be sunny


But that sunny? 207kWh min?
Irradiation:

I would assume ~40% more than yesterday so I am guestimating a solar engery output of ~61kWh today (most likely bit less).

Update with the result: 52.2kWh


“I” was 15% to optimistic. VRM by factor 4 wrong. I really would like to understand what Victron is calculating.