Siberian Snow Cover
Throughout October, the spread of snow cover from Siberia into Eurasia was ahead of climatological schedule.
The books have closed on October 2015 Eurasian snow cover and the numbers are impressive.
This chart snows a very robust Eurasian snow cover at the end of October:
The relative lack of snow cover in Alaska and western Canada doesn’t bother me at all. That is a reflection of the warm PDO+ pattern in the North Pacific that drove our consistent cold last winter.
October 2015 Eurasian snow cover ranked 6th out of the past 48 years. That’s not quite as high as the number 2 ranking achieved last year, but it’s still rather impressive:
For those who have just stumbled upon this site, this link will lead you to why a rapid spread of Siberian snow cover in October often bodes well for a cold winter here.
SST Anomalies
You can see the Big 3 players here:
- Warm PDO+ in North Pacific
- El Niño
- Warm western Atlantic
The strong El Niño has many long term forecasters predicting a mild winter for the eastern United States. But the warm PDO+ and rapid expansion of Siberian snow cover are two big things standing in the way of a typical boiler plate “super Niño” winter.
El Niño:
I’m not writing off the 2015 El Niño as a factor, especially when it’s one of the strongest in recent history.
The CFSv2 ensembles are showing the collapse of El Niño in 2016, weakening to moderate by late winter/early spring. Quite honestly, I’m not sure whether the collapse would occur fast enough to help us out:
I will say that if El Niño doesn’t show definite signs of weakening in December, this winter could be in trouble.
This panel shows two types of El Niño:
- Central or (Modoki) with the warm core around 150W
- Eastern with warm core near the South American Coast
Modoki El Niño events are tied to long term PNA+ ridging and usually result in cold, snowy winters for the eastern United States. Eastern El Niño events (like 1997-98) tend to put the subtropical jet stream into hyper-drive and keep the cold away from us.
But the 2015 El Niño is not strictly central or eastern. It’s a hybrid between the two, with the CFSv2 keeping the warm core centered around 120W for the winter:
The “tweener” factor, combined with the warm PDO+ and rapid spread of Siberian snow cover makes it difficult to determine exactly what effect El Niño will have on this winter.
Possible Early Winter Pattern:
The strong El Niño and the warm western Atlantic have me very concerned about the prevailing pattern for December into early January.
Persistent wet weather in the central United States over the past several months could favor a trough position that would result in a west-cutting storm track with the warm Atlantic pumping up the ridge over the southeastern United States:
As the cold pattern deepens and matures over the course of the winter, the storm track should sag further south and east. But I think December could be rather mild for the eastern United States.
Does this absolutely mean that Snodeo Weekend is a lost cause?
Not necessarily. It only takes one well placed-bomb at the right time to lay down the white carpet! December 2014 was nearly a complete bust. But this beauty dropped a foot of snow on ilsnow land just before Snodeo last year:
Short term:
The big picture looks rather boring through mid-November with the polar vortex stuck in the Arctic and PNA- trough over the western United States:
I’m not worried this will become the “winter pattern” because the SST anomalies and Siberian snow cover spread do not support it. As much as we want winters like 2002-03 when it started in November and continued into April, it doesn’t usually work like that.
Closing thoughts:
I’m trying to give you a general pattern of what I think will drive the weather this winter. My outlook is not meant for planning your trips or to help you decide whether to buy a new snowmobile. My motto is always be ready to ride when we have snow!
Assuming the 2015 El Niño begins to weaken in December, I believe we have a shot of a solid second half of the winter. The other “super Niños” of 1982-83 and 1997-98 did not have strong Siberian snow cover growth in October.
This could be a very interesting winter…
For the ilsnow nation,
Darrin
ps. My views on what might happen this winter caught the attention of Adirondack Life. You can check out their article at Adirondack Life Blog.
