Final answer:
The mountains in western Washington affect the weather in the area to the east of them by trapping larger clouds and causing higher precipitation on the western side, while the eastern side experiences a rain shadow effect.
Step-by-step explanation:
The mountains in western Washington most likely affect the weather in the area to the east of them by making it wet by trapping the larger clouds. When moist air from the Pacific Ocean encounters the mountains, it is forced to rise, cool, and condense, forming clouds. This process leads to precipitation on the western side of the mountains, while the eastern side experiences a rain shadow effect.
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