Because h5 isn’t just that. It’s 500mb which gives you a broader picture of ridges and troughs as well as blocking. Upper dynamics include 900 mb, 850, 700 which is respectively 2;000 ft, 5,000, and 10,000.
Man everyone around here is expecting a rainstorm Monday. I was talking to folks out shoveling when I walked the dog and when I said 6+ they looked at me like I had 4 heads....after they mentioned at least Monday is rain....