Well actually, distance wise, if you can see the White Gold Tower from Anvil or Leyawiin then you would easily be able to see it from southern Skyrin and further.
Here, see for yourself.

http://images.uesp.net/c/c3/TamrielMap.jpg

http://images.uesp.net//6/69/OB-map-Cyrodiil.jpg

However, if there were any obstructions between you and the White Gold Tower (the Jerall Mountains) then distance would be irrelevant.

Sorry, but up in Bruma you CANT see White Gold Tower.

That's because Bruma is a bit closer to the ground and doesn't show an unobstructed view of Cyrodiil. Dive Rock is even further north, but since it's so high up, you can see White Gold Tower from there.