Over the last week, I’ve watched the computer models bounce around. For the most part, the precipitation part of the models has calmed down to indicate two weeks of mostly dry weather for Arizona…or so I thought. The temperature models have been worse the last few days. Devastating cold and wonderful warmth are the walls the models are bouncing off. Yesterday, I almost wrote a post about how incredibly warm it would be next week. This morning, December 8 shows up in the computer models with Flagstaff 7-10 degrees below normal. By the following weekend, temperatures are 4 or 5 degrees above normal. I’m positive it will look different again tomorrow. But, why?
So, a few years ago, in a place off the western coast of North America, an anomalous blob of warm water (aka The Blob) gathered. It was following the Ridiculously Resilient Ridge. (How can a resilient ridge of high pressure, and a blob of warm water can get Wikipedia pages, and I can’t?) Both of these features interfered with forecasting because of the alterations they made to the weather patterns.
Well, the ridge is gone. Most likely this is because it ran out of ridiculousness. The warm blob is now gone, too. Not only gone, but currently replaced by a “cold blob.” The cold blob has yet to ascertain Wikipedia status. Below is the global sea surface temperature and temperature anomaly animation from the Climate Prediction Center.
Global Tropical Sea Surface Temperature Animation from the Climate Prediction Center. (23 November 2016)
You can watch the remnants of the warm blob fade away as the cold blob migrates from Eastern Russia to the east. Also, you can see the weak La Niña grow across the Equatorial Pacific. Both of these cold water features are going to make forecasting more complex. I think that’s why the forecasts keep bouncing around.
The Navy’s NoGaps forecast model has a bit of moisture in the forecast for the middle of next week. The GFS model has none, as of this post. This will be an interesting winter.
6-hour precipitation rate for Wednesday morning, December 7, 2016. From the US Navy