If Glass follows Escape Room:
3.7M
12M (inc. previews) Fri
10.4M Sat
6.4M Sun
28.8M
If it follows Insidious 4:
3.7M
23.8M (inc. previews) Fri
20.6M Sat
10.9M Sun
55.3M
If it follows Split:
3.7M
27M (inc. previews) Fri
30.5M Sat
16.4M Sun
73.9M
If it follows American Sniper:
3.7M
21.2M (inc. previews) Fri
24.1M Sat
17M Sun
12.5M Mon
62.3M 3-Day 74.8M 4-Day
Insidious seems like the best reference to go off of, since both are Blumhouse sequels, though there will obviously be a harsher Saturday drop and a softer Sunday drop for Glass. The thing to remember is the winter storm will put a big dent in this weekend's grosses, which none of these movies dealt with IIRC, so sub-50M for the three-day is still a strong possibility