Oslo is 9 hours ahead of Portland
Best overlap: 8:00 AM to 9:00 AM in Portland is 5:00 PM to 6:00 PM in Oslo.
Schedule calls for 8:00 AM to 9:00 AM in Portland — your colleagues in Oslo will be online from 5:00 PM to 6:00 PM. With overlap this short — around 1 hour — a recurring slot at 8:00 AM in Portland (5:00 PM in Oslo) is worth its weight in gold.