One other thing I can't explain
ICON model, see snow accumulated layer for Berlin next 5 days, 0.1 cm (=1mm)
0_1514633738477_Screenshot_20171230-122436-1280x800.png
And here forecast for Berlin, look at new snow values for next days
0_1514633431755_Screenshot_20171230-122645.jpg
Wind wave = wave generated by wind
Swell = wave that has moved outside its area of generation
At any given state, there may be multiple series of waves at your location. The wind could be blowing very hard at your location, creating wind waves. A strong cold front could be moving across the ocean, generating waves that will later arrive at your location and in the opposite direction of the wind waves. A third, or fourth swell could also be present.
as kitesurfer - i used the historical data to plan my surfing-trips worldwide. To see what have been dominant winds during a specific time of year on a spot.
i wouldn't mind paying for the feature.