We’re currently nearing the halfway point of the Northwest’s winter, and it’s interesting to gauge where we are by the weather.
In contrast to California, which is experiencing its wettest winter in a generation… if not longer… most of the Northwest has experienced a quiet winter so far, with thunderstorms. December ice storms are the main exception.
Let’s start with the temperature for the last 60 days (difference from normal, below).
The whole area is 0-4F cooler than usual, but eastern Washington and parts of eastern Oregon are MUCH cooler than usual…to 6-8F. Nothing particularly surprising for a La Nina year.
What about the difference in rainfall from normal over the past 60 days (below)?
A closer look at Washington at the difference in rainfall from normal over the past 60 days better shows the Cascades’ dry western slopes, while the eastern slopes are wetter than normal this usually.
Why this model you ask?
Good question! The reason is that we’ve got persistent low pressure offshore and higher pressure inland, leading to an easterly current heading offshore. So rainfall is more on the EAST of the Cascades but less rainfall on the western slopes of the Cascades.
To illustrate the situation, below you’ll see the 60-day average pressure ending January 11. High pressure inland (red), low pressure offshore (purple).
What about the Northwest snowpack? As shown below, snow and ice in Washington is almost normal this time of year. The same is true for all of Oregon except the southeast which gets more snow than usual.
At this point, I suspect Northwest will continue this quasi-normal regime for a while.
