To make you and the Englishman glorious I washed dishes , removed waste baskets swept the counters . I did not say the particles compress the air. Think about a small cloud the cloud have a certain volume (A), with ( K) particles as the cloud bumps into a second cloud of volume (B)with ( L) particles the two might have a volume A + B or will have a volume ( A + B ) - x , if the volume (A+B)-x then there will be a increase in concentration and this will make the particles be closer to each other we have to keep in mind there is air in between which is expressed in certain atmospheric pressure. . As clouds accumulate more and more the density of particles will increase more and more and the spacing will decrease and some air molecules will be dissolved in the particle and a collapse in the system takes place were large drops of liquid of water will come down. Well you guys can have your model and I will keep mine unless come with some better de tails instead hand waving.