They appear as perfect circles because they represent the range of specific weather radar stations. Inside each circle, precipitation data is being actively detected (in blue/green colors), but outside that range, the radar can't directly measure, so you see a sharp edge.
This effect often happens when:
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You're viewing composite weather radar where multiple stations overlap.
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The data source hasn’t smoothed or stitched the images seamlessly.
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The radar is focusing on specific areas (like monsoon rainfall zones) and the rings show its scan limits.
In short:
It’s not two giant storms — it’s the "footprint" of two radar stations picking up rain in their range.
If you want, I can zoom in on that area in a different satellite layer to confirm whether there's actual weather activity there.