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Argiope aurantia
You might try looking at Argiope (orb weaver that makes a pattern) on http://bugguide.net/node/view/2007 - - this website is where I identify many of the spiders and other bugs I am spotting.
It's a writing spider, you can tell with the white 'zigzags' in the web above and below the spider. http://www.projectnoah.org/spottings/817... - here is my spotting of a very similar spider, but you would have to check spiders in your area to get an exact match. Hope that helps. :)