It’s that time once again… as the leaves change color and fall to the ground, we begin to turn an eye on the coming winter season. Every year, at about this time, our thoughts start shifting to the winter… and to what horrors (or joys, depending on your point of view), it may hold. And while nobody knows the future… we will try to take a sneak peek into the looking glass, and see what the Hudson Valley may be in store for this winter.
We analyze a combination atmospheric and oceanic conditions. We look at the conditions as they exist today, as well as what those conditions are projected to be during the winter. Then we look back at historical data, and search for periods that were similar to what we are seeing now. We have used these analogs in conjunction with other trends and indicators… to create the Hudson Valley Weather 2015-2016 Winter Outlook:
Temperatures: 0.5° to 1.5° Below Average
When we talk about “Winter Temperatures” we are focusing on December, January and February (meteorological winter). Last winter (2014-2015) was 3.3° below average. The HVW 2014-2015 Winter Outlook called for temperatures 1° to 3° below average, so it was even colder than projected, thanks to a record cold February. This winter, while cold, doesn’t appear likely to be as intense as last winter.
After an October – November period that features several ups and downs… December appears likely to feature near to above average temperatures. December will likely be followed by a January and February with below average temperatures. A slow start to winter may catch some people by surprise, and cause them to let down their guard. But last December was much above average, and we all remember how last winter finished.
Snowfall: 25% to 50% Above Average
The snowfall projection covers the entire winter period (now thru April). Based on the data collected over the previous 25 years, Poughkeepsie’s average season snowfall is 46.7″. Last winter (2014-2015), Poughkeepsie saw 59.6″ of snow, which was 28% above average. This winter, we anticipate season snowfall totals between roughly 60″ and 70″ across the Hudson Valley. This projection has a high level of uncertainty, due in large part to the current strong El Niño. The drivers that helped provide the cold, snowy winter last year… are generally still in place. Exactly how those features interact with the strong El Niño, will determine just how snowy our winter is.
To arrive at the winter summary above, we performed a detailed analysis of historical trends and current projections. Using data from previous years where conditions were similar, we can project forward, and create an outlook for the coming winter. Lets take a look at what we expect month by month.
We expect winter to get off to a rather slow start. That’s not to say there can’t be cold outbreaks and bouts of snow, but in general, the month of December is likely to see near average, to slightly above average temperatures. The El Niño’s influence will be felt, and in conjunction, the warm waters of the North Pacific will only begin to favor the western ridge we have seen the past two winters. As a result, the cold snaps may be few and short in duration. This was also the case last winter, where Poughkeepsie saw December 2014 register 4.6° above average. This December may not be as warm… but there are plenty of reasons to think it will be a mild month.
January could be a big transition month for the Hudson Valley. As the western ridge builds into the winter, it should create a general trough in the eastern half of the United States. This general trend will be interesting to watch, because how that trough interacts with the moisture and storminess influenced by the El Niño… could translate into a chilly and stormy month of January. As mentioned above, the key to our seasonal snowfall totals, will be in the details.
It appears likely that, when compared to average, February will be the harshest month of the coming winter. By this time, the ridge and warmth may have once again locked into the western states, while repeated troughs drop in from Canada, with a continual supply of cold air. This map paints a frigid picture for the eastern US, but even so… it shouldn’t be nearly as bad as last February… when Poughkeepsie saw a February that was 13.0° below average.
With the influences of the El Niño continuing to provide an active storm track across the southern US, if the eastern trough is persistent, and we get the expected assistance of a negative North Atlantic Oscillation (-NAO), the jet stream could capture several storms and pull them up the coast in the form of nor’easters. It should make for a very busy forecasting winter.
Winter 2015-2016 (Dec, Jan, Feb)
When we combine the months together, you get a winter that looks like this. Very warm across the northern plains and northwest… and cooler than normal east of the Mississippi, with the chilliest winter in the southeast, mostly due to the numerous storms keeping it damp and chilly. The east coast generally sees above average snowfall with this sort of setup, as the El Niño provides the ingredients for snowstorms… the question is how often do the pieces come together?
By now, you’ve likely heard a wide variety of forecasts for the coming winter. Anything from “worse than last year”, to “a mild El Niño winter”. The reason is because we have a complicated setup for this coming winter.
A strong El Niño, generally influences the storm track across the southern United States by providing additional moisture, and creating a more active subtropical jet stream. Traditionally, the Hudson Valley would expect a mild winter and below normal snowfall during a strong El Niño. Here is what the winter temperatures looked like compared to average, during the strong El Niño winters of ’82-’83 and ’97-’98:
Those 2 El Niño winters were very warm across the northern half of the United States. But there are aspects of this El Niño that are very different from recent strong El Niños. Here is what the sea surface temperatures looked like in those two winters…
Notice the very strong El Niño (A), indicated by the very warm water in the tropical Pacific Ocean. Also notice how with the exception of the immediate coastline, all of the water in the northern Pacific Ocean is rather cool (B & C). How does this compare to the current sea surface temperatures?
In addition to the strong El Niño (A) like the previous example, notice how warm the northern Pacific is. The northern Pacific (C) is much, much warmer than the previous strong El Niños, and very similar to last winter… and surely, you remember what last winter was like…
With the exception of the strong El Niño (A), our current Pacific Ocean temperatures are quite similar to the conditions present during last winter (B & C). A winter that had ocean temperatures similar to last winter in the northern Pacific Ocean… as well as an El Niño like we have now, is the winter of 1957-1958…
The comparison is not perfect… but compared to how unique the combination of a strong El Niño (A) and warm northern Pacific (C) is, it is the closest comparison by far. What did the winter of 1957 and 1958 look like in the United States?
The winter of 1957-1958, with Pacific Ocean patterns quite similar to those currently in place, had a very similar outcome to what we expect this winter. By identifying what happened when conditions were similar in the past, we try to project what may occur this winter. So by using the analog winters displayed above, as well as some additional winters with similar characteristics… we are able to create our winter outlook. Hopefully this gives you a general understanding of how we arrived at our ideas.
We hope you enjoyed the 2015-2016 Winter Outlook. Please let us know what you thought, either in the comments section, or on the Facebook fan page. Also, be sure to check out our 2015-2016 Winter Outlook video on YouTube. And as always… we appreciate your endless support!