1. A method to illustrate a weather condition via a near-eye display system, the method comprising: displaying a representation of a geographic region via the near-eye display system; for each of a series of elevations above the geographic region, receiving a weather-data slice defining a weather-parameter value for each of a plurality of 2D coordinates at that elevation; constructing a volume-filling weather model based on the weather-parameter values received for each elevation and 2D coordinate; applying a digital filter and a coordinate transform to the volume-filling weather model to obtain a weather-display model, the weather-display model including a display-parameter value for each of a plurality of 3D coordinates; and displaying the weather-display model via the near-eye display system, co-registered to the representation of the geographic region.