It’d be really neat to be able to tune into altitude data, if it were available in the data set. I’m not sure what the best option is for trying to express that dimension of information on a 2D canvas though. At a fixed altitude, as the author mentions, vertical winds are simply expressed as low or zero movement, and tend to indicate what looks like shear boundaries for converging fronts.
Maybe a depth-fade render would look nice, with particles fading into high saturation and brightness as they move toward the viewer, and out to transparent (but not completely invisible) as they move toward the ground?
Windy gives altitude data, though it just does it by letting you select a given altitude to slice. What would be really neat is if nullschool let you rotate the globe and showed 3d airmasses.