Ahhh interesting. I thought ground clutter was removed during radar calibration or something. Is there a way to have automatic ground clutter filter on Windy ?
It is strange that it's not a constant problem though, because now it's gone, even on Windy. I wonder if temperature, moisture or other phenomenom can increase the ground clutter.
EDIT:
Well, it's well explained with also other info on the website you provided, thanks.
"Under highly stable atmospheric conditions (typically on calm, clear nights), the radar beam can be refracted almost directly into the ground at some distance from the radar, resulting in an area of intense-looking echoes."