Most 33"-advertised tires actually measure out to somewhere in the 32" (*EDIT* That's 32", not 22", sorry) range. I forget which tire it was, but one was even 31.XX". You are only going to be adding about an inch, give or take, so there won't be a real noticeable difference. The biggest difference is going to be felt due to changing from a street-oriented tire to a heavier and knobbier A/T or M/T tire.

Yep, none I've seen are that close to the "advertised" size and some are WAY smaller. I know a guy with Mickey Thompson ATZ 33x12.5x17s and they measure a hair UNDER 32". My 35x12.5x17 FCIIs measure out to 34 1/4".
I've seen some "bargain" brand tires rated at 35" measure barely over 33".

Toyo/Nitto seems to be about the closest, the 32" Terra Grapplers on my laid up Grand Cherokee measure out to about 31 5/8"...