Excessive Heat — Central Willamette Valley, Oregon

2015-06-26 to 2015-06-28 · Central Willamette Valley, Oregon

Event narrative

Afternoon temperatures were in the low to mid 90s which is around 20 degrees above normal. Nighttime temperatures were in the mid 60s to low 70s which is around 15 degrees above normal. There were several new daily records set for the warmest low temperatures. A man drowned while swimming in the Santiam River on June 28th.

Wider weather episode

A strong upper level ridge of high pressure resulted in hot temperatures across Northwest Oregon. Afternoon temperatures peaked in the low 90s to the low 100s which are around 20 degrees warmer than the seasonal normals. Monsoonal moisture and onshore winds resulted in fairly high humidities (40 to 50% in the afternoons) making the temperatures feel 2 to 5 degrees warmer than they were. The mid-level moisture also added to an increase of thunderstorms around the region. Clouds from these thunderstorms limited overnight radiation cooling. Nighttime temperatures were warm with minimum temperatures 10 to 15 degrees warmer than the seasonal normals.

Source: NOAA Storm Events Database, event_id 580570. Narrative written by the NWS forecast office that issued the report.