As far as I know I can use this structure(how + adjective + a/an + noun) with singular countable nouns. (The plural form is not possible, nor is using the definite article “the.” )
1- No matter how bad a mood you were in, you shouldn't have gone there. (okay)
2- How soft a pillow do you need? (okay)
3- How long the story is it going to be? (wrong)
But I have seen these following sentences on a journal website and now I am really confused. (I have just learnt the rule I wrote above. Before not knowing it these following sentences would be okay to me but now I don't get it.
4- I can't describe how bad the situation was all night. (I don't know why this one is okay according to the rule)
5- Waiting to hear just how bad the news is. (I don't know why this one is okay according to the rule)