Portland is heading into a burst of heat that could push temperatures into the 80s this weekend and keep the region warmer and drier than normal into early May. The city’s spring is already running as the 9th warmest on record, and the next stretch looks even more like summer than spring.
Forecast models show 850mb temperatures around or a little above +15 C late Saturday and Sunday, a setup that points to Portland finishing just below 80 on Saturday before moving well into the 80s on Sunday and Monday. Mid-upper 80s are possible in early May with this pattern, and record highs then are generally around 90.
This spring has not been uniformly hot. April brought a mix of cool, gray days and sunny, warm ones, but more than halfway through meteorological spring, most areas in the region are now seeing a Top 5-15 warmest spring so far. Rain has been close to average for most parts of the region, even as the warmth has built.
The bigger story is what that warmth is doing to the mountains. Most areas in the northern Oregon Cascades below 4,500 feet are already snow-free, and at 5,400 feet on Mt. Hood, 49 inches of snow still remain on the ground. The earliest snow-free date at that location is May 24, which shows how quickly the spring melt is advancing.
That matters because almost 3/4 of Oregon is in some form of drought, and the dry pattern expected over the next 7-10 days is likely to make the problem worse. Higher heights continue into the first week of May, the relatively warm and dry pattern is expected to continue into week 2, and the GFS precipitation anomaly forecast for the next 15 days is much drier than normal. By this weekend, potted plants outside are going to need watering.
The cold season is not gone, but it is being pushed aside. The warmth now reaching the Cascades and the Portland area is reducing snowpack, and as that snowpack disappears, drought conditions are spreading across the region. In practical terms, the answer to the question hanging over the next two weeks is clear: Portland Weather is set to stay unusually warm and dry, not just for a weekend, but well beyond it.
