How has the El Nino forecast held up in the Pacific Northwest so far?

PORTLAND, Ore. (KOIN) -- Warmer and drier. That's what the El Niño forecast called for in the PNW this winter. As equatorial waters warmed during the summer and fall, the forecast has held partially true for Oregon and Washington.

Accuracy of El Niño so far in Oregon

You're not imagining things. Temperatures have been warm in December across the Pacific Northwest. Portland has seen 23 days with above-average high temperatures.

That's in line with the typically warmer conditions seen during an El Niño winter. What's out of the ordinary is just how warm this December has been. When averaging the daytime highs and overnight lows and taking the average mean of all the days seen in December so far, 2023 comes in as the second-warmest December ever recorded in Portland.

Those above-average temperatures are expected to take Oregon and Washington into the first few days of 2024. That's due to a ridge of high-pressure building over the western half of the country.

This is an accurate depiction of what is normal for a winter that falls within the bounds of an El Niño year.

The downside of a warmer winter is the lack of snow over the Cascades. High-elevation rain and above-average temperatures continue to melt snow quickly above 5,000 ft.

Differences in the El Niño winter forecast for Oregon

Despite warmer-than-normal conditions in western Oregon, the rain has been in abundance. Typically, Portland should see less than average rainfall during an El Niño winter. The National Oceanic and Atmospheric Administration (NOAA) typically puts the PNW under the 'below' average precipitation area for the winter season when El Niño is present.

The impacts of multiple atmospheric rivers helped push Portland's December rainfall well above average. Typically, December is the wettest month of the year for The Rose City. That's holding true despite the season's drier outlook.

Portland has already seen a surplus of nearly 3.5" of rain so far in December. That's filled Portland's rain gauges to nearly 8.5". That's a big difference from the normal El Niño pattern seen in the Pacific Northwest during the winter months.

This increase in rain has continued to chip away at Oregon and Washington's ongoing drought situation. The only location in Oregon that still remains under the "severe" drought category is in the rain shadow of the Cascades in north central Oregon.

A surplus in rain doesn't mean the Cascades are seeing the same when it comes to snow. Oregon's snowpack remains low as warmer temperatures continue to melt any fallen snow.

Winter is only a week old. So, these warmer and wetter conditions are still subject to change and aline with the typical El Niño climate patterns seen in years past.