It’s clear to see that the El Nino is the main driver starting off winter 2015-16 and not just over the US but globally.

Just look at how warm the continents are but this opening week has been a blow torch over the heart of North America and Eurasia. This will excite the global warming crowd I’m sure.

The combination of warmth further north through an enhanced subtropical ridge and subtropical jet primarily down to this years Nino, there’s also a much stronger than normal westerly flow thanks to the strong +AO/NAO. The strong positive may well be a side reaction to the energy being released into the atmosphere from the Nino but all this is sure making for a warm, wet open to the 15-16 season.

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With the strong westerly, oceanic influence comes a stormy pattern and as shown in yesterday’s post, the Pacific jet is strengthening and so the West Coast is likely to get hit each day this week by a separate low, this will sure pile in the moisture in the form of rain and snow.

While beneficial Out West, it’s all about the warmth further east as lowering heights in the west correspond to height rises further east and southerly flow.

As we progress through the month and rather than it being a warm month across the board, I suspect a cold West, warm East, something similar to December 1984 because cold, potentially Siberian source air will get into the Western US but it looks as though the heights hold above normal in the east.

The GFS ensemble 5-day mean 500mb height anomalies show the Alaska to Arizona trough as we head deeper into mid and late month but a still above normal height field up the eastern side of the continent. With this and potential for Siberian air driving into the Great Basin, we could wind up with a temp profile very similar to Dec ’84.

2 metre temp anomalies are going with the colder west, warm east.

Big snows to come for the West this month, sets the stage for major cold Dec 15-25.

GFS snow forecast over the next 10 days.

Polar vortex displacement towards Asia would suggest some cross polar flow and Siberian air getting into the Western US 10-15 days from now.

Stay tuned, video will be available a little later this evening.

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