Simple, ya can't have air pressure without containment.
Oh really?
So if you boil some water in a kettle, and it starts boiling, and you put a piece of paper or paper towel or tissue over the spout, what happens to it? Does it start to be pushed up? You know, because of the pressure?
Pressure that isn't in a container.... Huh, almost like you CAN have pressure without a container.
Wind and temperature are influencing factors in the cause of pressure gradients.
Wind is the result of temperature and pressure differences in the atmosphere....
Temperature affects how fast atoms move, causing greater or lesser pressure.
There are no significant pressure gradients within a sealed container.
There is NO pressure being exerted on the inside surfaces of a vacuum chamber. That lack of pressure is what causes the train car to implode. It's made for keeping pressure under containment, not withstanding the pressure from external forces.
Every time my furnace kicks on it creates wind, in my outside tank, causing pressure gradients.
But that's not a container, now is it?
I thought you said pressure requires containment. Are you now backtracking?
Again, a gas exerts pressure evenly across all surfaces of the container it is within. You haven't addressed this.