Hi,
Every so often SkyDemon paints a CTA from sea level to FL140, extending about 15 mile radius. Tonight it appeared as notamed from 2100-2110. I can't work out where it's coming from, as it's not listed in the normal notams. Is it spurious?
Thanks in advance. PS. I have a screen shot of today's appearance.

We won't be "painting a CTA", we will be depicting a NOTAM. A screenshot would of course be helpful, if you'd like to post it here.

Hope the upload works.

Thanks Sylvester. That is a NOTAM you're seeing, not a CTA. It's a NOTAM which is you read it, is affecting the CTA.

So, the notam only applies to the three CTA areas of the Norwich zone? The circle on SkyDemon is not the outer limits of the airspace, but the 0-140 extension only affects the original mapped zone?

All NOTAMs are basically big circles of influence. You have to read the NOTAM text to find out what is going on. They have created a circle in this case which contains the pieces of airspace affected by it.