Is Tomorrow Going to be an Encore day for the Steam Sale?

most probably yes

I really hope monaco is going 80% again, missed it >.<

It also will be on sale on Winter sale aswell, which is only like 2 or 3 weeks away I think.
I'm not sure if there's going to be an Encore, Doubt it though.

Wait for the Winter sale in two weeks, it'll definitely be in that sale.

Odd that Fallout hasn't been a daily or flash sale.

Not likely, the leaked date was to the 3rd, not including the 3rd.

will there be another daily tomorrow or will it end?

AFAIK, there weren't encores in other Autumn Sales, so they probably won't change their tradition. Wait for Xmas sale.

Hmm, maybe Bethesda wants to make some bigger sale for rumored-Fallout-4-announcement?

The sale ends tomorrow at 10am PST so if you want to grab something it has to be today.

Fallout didn't hit 75% during this sale but it certainly will in a few weeks during winter sale.. just wait for it then.