True, but the eddy currents (turbulence) when the blades are turning ARE visible to Doppler...that's how Doppler is able to detect winds. Doppler doesn't require a metallic target. It picks up minute particles and droplets that are moving in the winds. When there is little or no wind...no problem, but the stronger the wind, the more interference is created and shows up quite well on a WSR88-D.
Been there...watched it happen. But didn't get the t-shirt.
Yep, you are right. I was thinking specifically of the blades and why they would cause such reflection. I wasn't considering water vapor or wind distortion being picked up by the Doppler. Amazing stuff, huh?