The paper seems quite readable to me and I also lack the training. But this point is adressed in the beginning. "The highly non-linear physics of weather means

The paper seems quite readable to me and I also lack the training. But this point is adressed in the beginning. "The highly non-linear physics of weather means that small initial uncertainties and errors can rapidly grow into large uncertainties about the future. Making important decisions often requires knowing not just a single probable scenario but the range of possible scenarios and how likely they are to occur."