To me, the code descriptions I found mean:
Green - think about scrambling
Blue - communicate about scrambling
Yellow - watch the areas we might have to scramble
Orange - tighten security before scrambling
Red - scramble!

Now, being a painter, I see the color code levels a little differently than they were assigned. If I had not read their list, I would have guessed that blue was the lowest level of alert. Blue (1)... mix a little yellow and you get Green (2).., take out all the blue and you get Yellow (3)... add some red and you get Orange (4).... take away yellow and you get Red (5).

Notice there is nothing really practical told to civilian citizens about how to respond to these alerts.

Alice