Empty Cone Above Winchester On Radar - Artifact Or Real?

[trevw]

Hi,

I realize that the radar is not perfect and wouldn't expect it to be - I have noticed however that there is almost always a cone shape on it's side over winchester that doesn't contain precipitation.. anyone know whether it is a radar artifact (no coverage or something blocking the radar) or a real gap in the preciptation perhaps caused by some geographical feature (we do seem to get generally less precipitation here than elsewhere - especially basingstoke than just down the road). I've attached an image that shows the gap..

thanks

Trev