The National Weather Service is monitoring widespread clouds across northwest Oregon early Tuesday as a weak shortwave trough continues to hold onshore flow over the coast. The city of Portland, Oregon, is expected to see a high temp of about 64 degrees Tuesday, but this is about the end of below-average highs this week. Temperatures are expected to rise as an upper-level ridge over the northeast Pacific Ocean shifts into the Pacific Northwest. The chances of Portland/Vancouver reaching 80 degrees Thursday stand at about 50-70% under mostly sunny skies, with areas south of Portland along Interstate 5 expected to have a 15-25% chance of reaching 80. Meanwhile, extended forecasts are optimistic about high temps climbing into the 80s by Sunday, nearly 20 degrees above average during early May.