What does a solar eclipse at 99% totality look like?
At 99% the sun will be reduced to a small sliver. There are simulations on the internet. It will become very notably darker. However, the sun is 400000 times brighter than the full moon, so 1% of the Sun is still 4000 times brighter than the Moon, and so no corona will be visible. You can still damage you eye looking at that sliver.

Since the centre of totality is less than an hour's drive from Portland, if you have a car, and can get out early, you can see totality and the corona (weather permitting)