Don't know if WU handles moving stations, unless you have a GPS position to report the data. You can buy vehicle mounted weather stations, but they seem to be oriented towards emergency responder deployment.
Anyways, who wants to drive around with a large antenna thingy? But I've seen HAM Radio aficionados drive around with a dozen antennas on their (usually beater) cars. Then you have the storm chasers with doppler radar and what not, lol.
Not all vehicles have enough of the sensors needed. Of the sensors you might have available on the CAN bus: sun sensor (dash day/night modes), rain sensors (automatic wipers), light sensor (automatic low/high beam), temperature sensor (for hvac), barometric pressure, ... Such sensors tend to be low resolution and not very accurate. I don't think we could measure wind speed on a moving vehicle too well.
Some vehicles have vertical accelerometers, but that might be useful for road roughness measurement and pot hole detection.