Soap tells all?

I came back from a storm chase this evening (southern Manitoba, and we got some good towers, okay structure and that's about it, and if I remember I may post some pictures), went into the bathroom and there was liquid soap all over the counter. It had come out of the dispenser spontaneously.

What, I thought, would cause that to happen?

Well, I thought about it and realized that a) the approach of a surface trough would decrease the downward pressure on the soap, and b) the moisture in the air (this was by far the most humid day thus far this year) would cause the air inside my house (and thus, inside the soap dispenser) to be more buoyant, causing it to rise. Thirdly, and sort of related to the first 2 things, is that there was an upper-level short-wave trough approaching. Because of some mathematically-explainable stuff, ahead of the trough axis, the air in the entire column was rising, lessening (again) the downward pressure on the soap.

The things we nerds think about.