A broad ridge over the northeast Pacific is beginning to shift eastward, initiating a trend towards modestly cooler temperatures across the Willamette Valley. Today presents an exception, with high temperatures generally reaching the mid to upper 80s across the interior lowlands. Coastal areas will experience cooler conditions, with highs in the 60s.
Increasing onshore flow will establish this afternoon and evening, with winds turning westerly as a stronger marine push develops tonight. This marine air is expected to spread inland through the overnight hours, with any lingering warmth displaced east of the Cascades by Thursday. Reduced visibility, primarily near the coastline, may also develop…