Thanks - I hadn't come across that cloud formation but that sounds spot on:
I just checked the date. It was Jan 2 at about 3.15pm, facing southwest. Looking at the satellite view from a bit earlier that day you can see the bands of cirrus ahead of the cloud which was moving up from the south. The cloud "rays" were aligned SW-NE so they would have been pointing almost directly at the camera, appearing to converge due to perspective.
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Dude... Which satellite view did you use in this post? I am a keen cloud-spotter and have always wanted to use a satellite that shows up clouds in such amazing detail!