It is needle or tip blight, a fungal disease that is encouraged by damp, humid weather and our wet spring so far is a prime incubator of this problem. Most established weeping Atlas cedars will show some symptoms of this in mid to late spring or early in our climate. Generally not a huge problem and can be controlled by pruning out infected portions but it typically runs its course with the season. Extreme infections can be treated with an appropriate fungicide but this is not often necessary.

Here is a link that might be useful: Cedrus tip blight

Thirty years ago I tried growing a weeping Atlas Cedar and got the same thing. I asked about as to what was wrong with it and everybody said spidermites. That didn't seem right as spidermites will be all over the plant and not patchy like what was happening. Besides I looked very close at the foliage with a magnifying glass and couldn't find any mites. After several years I got rid of the tree.
Thank you GardenGal for the info! Finally mystery solved.
In the meantime I was growing several varieties of Cedrus deodaras that were barely, if ever, showing signs of the tip blight.
Fast forward to the present and a few problems have cropped up. A large Cedrus deodara with some gold in it has shown signs of the tip blight more this year than ever before. Read cool, wet, Spring. It is also being severely weakened by Sapsuckers and will have to be taken down. Those birds are beginning to be more than a nuisance.
A couple of years ago a friend gave me a Cedrus atlantica, 'Aurea'. Last year it had tip blight, but I thought, I will give it one more year. This year year it looks like this.
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Needless to say it's going to be taken out.
Even though it's planted in almost full sun and very good drainage, it's just too wet here in the foothills for a tree that naturally grows in a drier climate. I guess that's why the Deodaras are more resistant to tip blight.
Anyone in a drier area want a Cedrus atlantica, 'Aurea'? It's got a good rootball,... for an Atlantica.

What is usually sold under the name is 'Aurea Robusta'. It amounts to a Blue Atlas Cedar with yellow on top, can be quite nice.