Yes porcelain would be the correct type of tile to use. When tiling outdoor areas, the slab has to be sloped so that all of the water runs off. The spec is a min. of 1/4" per ft. You will never see that much slope built in a patio by the concrete guys tho unless the slab was built with tiling in mind.
So, this slab is not a good candidate for tiles, even in Houston. If you insist, you have to get rid of the birdbath. You also MUST have either expansion joints or control joints every 8-12 ft. both in the slab and in the tilework directly above in the field and around the perimeter.