I also live here in the NW and wind will tear that tarp down with those poles at least it would where I am at. A standard tarp is much cheaper and so is some PVC or 2x4's look at some of the simple hoop coops that is a design that would hold together better for the long term meaning all winter...
Schedule 40 PVC and a tarp would be better and cheaper than what you have linked. Make a frame for a roof from schedule 40 PVC use either 3/4" or 1" make bows over the area tie it all together and pull a tarp over it use wire or zip ties or both. I built a roof for a large dog kennel this way...