well there is no picture but i can tell you what the anwser most likely is from living in WA
Anwser
The places regions that get the most rain are on the coast and the dry parts are on the east side behind the cascade mountains. The west side doesn't get any rain because the cascade mountains force the clouds to presipacte down on the coast side. Leading to the coast getting the most rain and the east side getting the most side.
