A WebmasterWorld thread asks how much of an impact will a site see if it is moved from a Dubai host to a USA based host? The answer is not really all that known.
This webmaster's main concern is that he receives "80% of traffic from UAE and have lots of content and back links related to UAE." He wants to continue to receive higher rankings in the United Arab Emirates (UAE) regions. He is concerned that by moving his site to a host in the US, it will drop his rankings for searches conducted in the United Arab Emirates region.
Senior member, wheel, said that when he moved a site from one country into the US, he said Google has yet to pick up on that change. He said, he had a "heck of a time getting Google to realize it was a US site." Wheel explained that the site still comes up for "country specific searches" in the old region.
The overall recommendation is that the webmaster continue to obtain links from the UAE region. Plus, if possible, specific in Google Webmaster Tools that the site is specific towards that UAE region. But before doing that, Tedster warns, specifying the region in Webmaster Tools may result in you "forfeiting a lot of international traffic."
I'll track this thread and write a new post based on the results seen by this specific webmaster.
Forum discussion at WebmasterWorld.