Bear in mind that sometimes it is difficult to know whether the speaker is using the subjunctive to convey a future idea or a shared information. Have a look again at this example:
Aunque esté nevando, voy a sacar al perro a pasear.
There are two possibilities here:
the speaker is thinking that it might snow later (but even so, nonetheless, he is taking the dog for a walk)
the speaker and the listener both know that it is snowing at that moment of speaking (but even so / nonethelesss, he is going to take the dog for a walk), so it is a background/shared information.
In this sentence, how can one say "aunque este nevando" and be speaking about the future? This seems like it would have to be an instance of shared information, right?