Upper Mid and surface CAA

[Silverbird]

Good Morning - 

A recently got this question wrong (and I'm paraphrasing from memory):

You have cold air advection in the upper, mid, and lower levels what can you expect to happen to the heights/prssure in these levels?

B R E A K 

I put fall, fall, fall and got it wrong, the right answer was fall, fall, rise. 

So, dynamically, the upper and mid heights would fall due to the colder denser air dropping them and the low/sfc pressure would rise because it has nowhere to sink to thus adding mass at the surface? 

Thanks in advance...

[Ellinwood]

It appears that the question refers to the upper and mid levels for heights, and the pressure for the lower levels (surface).

Heights in the upper and mid levels fall because the colder air coming in during CAA is denser. It is denser because the air molecules aren't moving as fast and can be closer together.

Pressure rises in the lower levels (surface) because of the denser air. The denser air allows more air molecules to fit into the full vertical column of the atmosphere. More molecules = more pressure.

[Silverbird]

Many Thanks. It made sense after I saw the correct answer but I wanted to make sure my reasoning was dynamically sound.