Weather Wise - Weather Forecast
published: November 4th 2016
by: Brian Bledsoe
Is our recent very warm weather anything out of the ordinary? Not particularly. Much of the United States is usually quite warm following a strong El Niño. The graphic below shows what a typical September and October looks like after a strong El Niño...1983 and 1998 are used as examples:
All of that yellow, orange, and red represents MUCH warmer than average temperatures. So, this warm weather should not come as any surprise.
What is up with the oceans and La Niña? Well, La Niña is still in the developing stages, but really hasn't been fully reflected in the atmosphere. You can clearly see the colder than average water off the West Coast of South America:
The coolest water associated with the developing La Niña is located in the Central Pacific Ocean versus just off the coast of South America. This feature will also likely have implications for the upcoming winter. You can also see warmer than average water off the West Coast of the United States and MUCH warmer than average water in the Gulf of Alaska.
Good common sense tells us that if the water surrounding a land mass is warmer than average, the land should be warmer than average. No surprise here... This sea surface temperature pattern is still associated with a positive/warm phase of the Pacific Decadal Oscillation. However, the PDO has cooled quite a bit recently. The graphic below charts the PDO Index back to 2005:
While the PDO is much cooler than it was just a few months ago, it is still positive. A positive/warm PDO usually does not produce a pattern favorable for colder than average weather for us. In fact, it is usually the opposite...especially when other forces are at work.
What are the oceanic and atmospheric teleconnections doing? See below:
All of the major teleconnections tied to the Pacific Ocean have been or are in a very positive mode. When considering this, the PNA seems to have the biggest impact on us right now. A very positive Pacific / North American Oscillation (PNA) floods us with warm Pacific air and keeps most of us warmer than average.
CFSv2 Model Temperature Forecast:
CFSv2 Model Precipitation Forecast:
With this particular model, you can clearly see the trend toward a warmer than average winter.
The CFSv2 also shows a pretty stout dry signal across parts of Texas.
I won't go through every model here but did want to show you the NMME Model and what is is showing. Remember, the NMME stands for North American Multi-Model Ensemble. I.E. it is looking at a bunch of different models.
NMME Model Temperature Forecast:
NMME Model Precipitation Forecast:
Like the CFSv2 Model, the NMME (which does include the CFSv2 Model) is showing a warm winter. It is also showing that same stout dry signal for Texas and much of The South. Based on the current trend and what is likely to occur in the coming months, I can't disagree with that.
Regarding temperature, I think it is a pretty done deal that our winter will be warmer than average overall, especially the farther west you live. Areas farther east will eventually get colder, but that may also take a while.
It may sound all like doom and gloom, but I do think there is a chance for us to turn the corner in the spring, and of course we won't stay 80 degrees forever. Computer models suggest that any La Niña impact will weaken sufficiently in the spring. The graphic below shows that trend, with the yellow line being the mean of all the computer models sampled:
If we are going to see a period of time that could potentially allow us to see more active and potentially wetter type weather, it would be during the spring. I remain somewhat skeptical, but at least we may have a better chance.