I notice this radially symmetric weather radar pattern over London, UK today.
Is this a real weather pattern, or a measurement or model artefact? If it is a real weather pattern, what causes it?
The image is from https://www.netweather.tv/live-weather/radar, which shows the following legend under the chart:
Weather Type Radar The weather type detection uses a combination of hi-resolution model data, along with ground observations to show whether rain, sleet, snow, hail or freezing rain is falling. It's an excellent guide, but bear in mind that in very localised situations some variation may occur.
The pattern seems to have started developing at around 21:35 BST today 2023-07-19.
Edit: I've added an additional image that shows a more dramatic pattern from today 2023-07-22 superimposed on a real rainfall pattern, together with a red dot at postcode HP3 0EJ in the village of Bovingdon (relevant because of the Bovingdon arrival stack for Heathrow airport).