Weather models are made primarily for making good weather forecasts in the mid-latitudes, i.e. Europe and north America. They are also made to be able to calculate forecasts fast enough to be helpful on computers that are not as fast as the current computers. Therefore we have used a lot of short cuts that are not physical. PhDs as Marvin Kähnert are working on improving the models in the Arctic and introduce more physical correct assumptions.
Music by Lee Rosevere - Arcade montage, B.Y. 3.0.