A forecast for strong auroras, the result of powerful solar flares both on Monday and again Thursday, is expected for this evening through tomorrow morning (September 12-13). Astronomers are predicting that the best time to see the northern lights will be after midnight, but they could be visible as soon as it gets dark.
Portland area weather forecasts clear skies for Friday evening. Viewing will likely be best away from city lights.
For more information, click this link:
Northern Lights May Ignite in Northeast, Central US Skies: Where to See Rare Show – AccuWeather.com