As I begin to prepare my winter forecast each year, my main goal is always to identify what is going to drive the upcoming winter. You may be asking yourself why in the world I would even attempt to put out a winter forecast this early. Some would even argue that seasonal forecasts are pointless and inaccurate. By putting out an early winter forecast, it allows me to take all of my research thus far on the upcoming winter and put it all together in a way that reveals to me what will likely take place this winter. I just happen to make that information freely available to you also! Seasonal forecasts can be very accurate if the right assumptions are made and if you interpret correctly what will occur as a result. If you’re wrong on your assumptions for the upcoming winter, then the forecast will likely be completely off. I will show you what I think is going to happen this upcoming winter, and why I think it will happen. I will explain all of my certainties and my uncertainties for this upcoming winter. My final winter forecast will be released in October, which will be a revised and more-detailed version of this preliminary outlook.
Most of you heard all of the talk earlier this year about the so-called super El Nino that was going to develop by this winter, but I really never bought into that happening. There’s no denying that there were similarities between this year and the developing super El Nino of 1997-98, but there were also some major differences. The atmosphere did not react in a way that would necessarily be expected for a coming strong El Nino, and we are now seeing strong indications that the upcoming winter will likely bring a weak El Nino. This means that this upcoming winter will only partially be driven by El Nino, and that there will be other potentially bigger drivers that could influence the United States winter. We saw a similar situation occur last winter, where we were in a neutral ENSO pattern with other variables driving the winter instead.
So I need to know how strong the El Nino is going to be, and where the location of the warmest waters along the equatorial Pacific will be at this winter. No, we are not going to be going into a Super El Nino, which would have brought us an entirely different winter than we are going to get. Typically when you have stronger El Nino events, the polar jet stream stays further to the north, trapping that Arctic air north and not impacting the United States. However, when you get a weaker El Nino, that doesn’t usually happen because you have other variables that often influence the weather more. That makes it a little more tricky because you have to start identifying those other factors.
To keep things simple, you have an El Nino when sea surface temperatures are above average for an extended period of time over the east-central tropical Pacific. I wrote an article about a month ago explaining what an El Nino was and how it developed, so be sure to check that out if you have any unanswered questions. Another very important factor to take into account is where those warmer waters are located. The difference between having a more west-based vs. east-based El Nino makes a HUGE difference in what the winter will be like. Right now, the warmer waters are in the eastern Pacific, but that is going to likely shift over the next two to three months. You’ll start to notice that the region of warmer waters will be over the central Pacific, surrounded by cooler waters on both sides.
So far, I have identified two very important factors: that the El Nino will likely be weaker, and that it will likely be a more west-based El Nino, which I will refer to as El Nino Modoki. Our last El Nino Modoki occurred in 2009-10, and this phenomenon has been more common in recent decades. The reason I have went through all of this explanation is to show you why you can’t simply come to the conclusion on what the winter will be like simply by saying that it’ll be an El Nino winter. Strength and location DO matter!
Here are the predicted sea surface temperatures: one from June through August and one from December to February. Notice how the warmest temperatures shift from the eastern Pacific and move westward towards the central Pacific by this upcoming winter.
Now that you’ve had to read through all of that, allow me to start making some predictions, followed by even more explanation on why I feel so strongly about these predictions. I am seeing strong indications that the central and eastern United States will see another brutally cold winter with some areas in the eastern United States potentially getting even colder temperatures than last winter. This will partially be driven by El Nino Modoki, and I’ll explain one of the other main drivers later in this article.
When you have an El Nino Modoki, temperatures across the United States can be a lot different than what you would have with a more east-based El Nino. With an El Nino Modoki, you typically have temperatures that are above average in the Pacific Northwest and below average in the southeastern United States. Now, that’s not saying that other regions will have only average temperatures (which is far from the truth), but that the Pacific Northwest and Southeast are typically the two regions that have the largest departures from average temperatures during El Nino Modoki years. Again, the 2009-10 winter is the most recent winter where we can see this occurring as a result of this type of El Nino. Obviously, the stronger the El Nino Modoki, the more likely this is to be a main driver, but as I stated, this El Nino will likely be weaker.
I believe that El Nino is going to be a factor this year, but I don’t think it will be the only driver or even the main driver of this winter. If you look at a sea surface temperature map again, you’ll notice above average sea surface temps in the northeast Pacific Ocean in the Gulf of Alaska. You can thank those warmer temperatures for the ridging that built up over Alaska and the western United States last winter, which caused the brutally cold winter for the central and eastern United States. With the combination of the weak El Nino Modoki likely setting up and the likelihood of sea surface temperatures remaining above normal over the Gulf of Alaska, this winter could, in fact, be colder for the eastern United States than last winter, and likely just as cold in the central United States. The western United States would again have above average temperatures with the Pacific Northwest having the highest departures from average. In fact, the Pacific Northwest could be warmer than last winter, while the southwestern United States could have similar temperatures to last winter.
Like I stated above, some of the coldest temperatures could end up being more focused in the eastern United States, where even Florida could get in on the below-average temperatures. Florida actually generally had above-average temperatures last winter, while the rest of the East experienced bitter cold. I don’t think that this will be the case this year, as the Arctic air could push well to the South. The only exception that I see to this is Maine having average to maybe above-average temperatures, but that is still questionable and a difficult call.
The sub-tropical jet stream will likely be very active across the South, where regions from the Southern Plains to the Southeast on up to the Mid-Atlantic and Northeast will likely get plenty of snow/ice this year. I do expect there to be several big storms this year, and places that typically do not get snow or ice will get it this year. I will continue to watch how strong of an El Nino takes hold, and that will play somewhat of a role as to how wet things end up being. We could have several storms that bomb off the East Coast again this year, so regions up the East Coast could get hammered. Again, areas from the Southern Plains to the Southeast will likely get snow/ice, and there will likely end up being a lot of talk about how unusual this upcoming winter is for those areas.
Southern California and surrounding regions will likely get some relief from the drought as I expect precipitation to be average to above-average. This is another one of those things that I am still questioning; however, I do see good indications of a wetter-season. Waters are very warm off the Californian coast, and the pattern could favor some big rain events for that area this winter. I’ll continue to keep a close watch on that, and if I need to make changes on that prediction by this October, I will.
Once you get up to the Pacific Northwest, it will end up being warm and likely very dry. Again, that is the region that could end up experiencing temperatures well above-average. I’m thinking that the western United States will generally have above average temperatures, and most likely, below-average snowfall/precip. We will probably have another winter where there will be a lot of ridging over that area.
The Northern Plains and Midwest will likely have below-average temperatures. In fact, temperatures could end up being quite brutal at times due to troughing that will likely set up over the region this winter. We could have another polar-vortex driven winter, where pieces of the vortex break off and push well to the south. This is a similar scenario that occurred last winter and could in fact happen again this winter.
There are several other indications that are pointing to another cold winter in the central and eastern United States. A combination of several climate models are showing that precipitation will be higher over Eurasia come this October. High snow cover over this region in October can lead to colder temperatures in the eastern United States the following winter. The theory that higher snow cover over Eurasia in October translates to a colder winter in the eastern US has held up quite well over the years. I believe that this also takes into account the rate of snow-cover change over this timeframe.
Sunspot activity is also a factor that I often look into when I’m putting together a winter forecast. This is something that I will likely look into more when I’m putting together my final winter forecast in October, but generally, sunspot activity has been decreasing in recent months. In fact, we just had our first spotless day since 2011 just a few days ago. Winters tend to be colder when there is a lack of sunspot activity, so if this trend continues, that could be another variable that drives temperatures down across the United States this winter.
Sea surface temperatures across parts of the Atlantic need to be watched closely this year also. Ridging over the northern Atlantic can lock the central and eastern United States into a cold pattern if you have ridging out over Alaska and the western US. Sea surfaces temperatures play a big role in this occurring, which is why it’s important to have a good handle on predicting what’s going to occur in the oceans.
Throughout this year leading up to this winter, I will continue to give you more information and updates as I get them. It’s still July, so there will be some changes that have to be made between now and this winter. As I stated above, I will be putting out a final winter forecast in October, and it will break things down even further than I did in this preliminary forecast. If you currently don’t like the Firsthand Weather Facebook page, click here. I will be putting out a lot of updates on there regarding this winter, and you definitely don’t want to miss those!!
Thanks for taking the time to read this preliminary winter forecast, and I can only hope that you get the kind of winter that you’re wishing for!
Matthew Holliday (Curriculum Vitae - Resume) is a graduate of the University of Oklahoma, where he completed a B.S. in Meteorology and a B.S. in Geographic Information Science. He completed his master's degree in meteorology and climatology at Mississippi State University and is currently pursing a Ph.D. in Earth and Atmospheric Sciences.