Therefore, ASOS will not report any cloud layer above 12,000. The next descriptions relate directly to the number of eighths covered by clouds in the celestial dome. Remember that a broken layer is also a ceiling. Now I will discuss the first part of the equation and as an observer, I find it the most interesting. Remember that the layers are additive from an observation point of reference.
Lets look at an example of how layers are added.
This is a broken layer. This by definition is a scattered layer. However, in this example the 8,000-foot layer covers that area of the dome not covered by the layer at 3,500. Therefore, the layer at 8,000 feet is OVC 080, or overcast 8,000. Sooooo if you are flying along in your trusty 150 at 4,500 and look up and see a scattered layer of clouds at 8,000 ASOS will call that layer overcast.