If you can get east of the Cascades from Portland, that would be your surest bet. Even if the weather is expected to be clear in the Willamette Valley on the 21

If you can get east of the Cascades from Portland, that would be your surest bet. Even if the weather is expected to be clear in the Willamette Valley on the 21st, there is a risk that the marine layer could settle in and not clear by the time of the eclipse. The risk is less in August than now, in June, but it could happen.