The upper level pattern we saw for much of December 2025 was essentially identical to the March SW heat dome pattern. Very different results on the ground though. Massive PNW blowtorch while the Central Valley in CA was trapped under an extended tule fog inversion in December. By March, inversion season is long gone and North Pacific SSTs are at their annual nadir.

Well you see, everyone loves warmer climates and its actually good for the plants. Now if you will excuse me, I am on my way to go ignite some methane hydrates and test their ignition point at 9600ft below sea level.

Daniel Swain had some pretty good insight into how an atmospheric river over Washington state influenced the record breaking ridge over the desert SW back in March

There are so many subtleties to our regional climate which unfortunately gives fuel to the statistic cherry pickers. The warming is highly asymmetrical on a seasonal scale with summer warming being dominant and wet season warming being more subtle and generally felt more in terms of low-to-middle elevation snowpack. Then you have the Columbia river project which continues to keep irrigated areas several degrees cooler in summer than they would be if they were compared directly to pre-1950s climate. Plus all of the decadal and multi-decadal ocean current variability which Phil is constantly hammering us about. Oh—and lots of new research indicating a direct connection between the warming Pacific Ocean and western US heatwaves via latent heat release in atmospheric rivers. A new study on the connection with the 2021 heatwave just came out: https://cw3e.ucsd.edu/cw3e-publication-notice-the-role-of-an-atmospheric-river-in-amplifying-the-june-2021-western-north-american-heat-wave/

What's more unbelievable than that is what it has for DJF overall (and it's had this kind of look for multiple runs now). This despite it also showing a super Nino. There is no known precedent for a temp layout like this in a higher end strong/super Nino, so I continue to be skeptical. Depending on how fast the Nino weakens along with some other factors, there's a possibility that parts of January or February could offer up something that resembles winter for us, but we'll see. I would at least lean toward it being more likely to have a favorable stretch in that timeframe compared to December.