I have seen numerous thing in the MP level outpost which makes me believe it is set on the cliffhanger level.

towards the spetsnaz spawn i think (the one hear the little cave sort of thing) and the control tower you can see the refuelling things roach blew up (not the same obviously) and past the fence you can see some fighter planes like the ones from the cliffhanger airfield. i might be wrong BUT ask yourself this. why put a snow map in when no levels are set during a snowstorm also there wasn't a snowstorm after the mission turbulence but i think they added the storm afterwards.

it might be delta force because TF141 doesn't properly exist in MW3