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The developing weather pattern for December, (the first month of meteorological winter) continues to be a fascinating challenge to unravel. The U.S. based GFS and the EURO are at odds with their respective MJO forecasts, the GFS going to cold phases while the EURO goes full bore into warm ones.

The EURO is usually my bread and butter but as I've mentioned here recently that model has not handled cold in the pattern recently as well as the GEFS. For that reason I've been leaning more on the GEFS with it's consistent depiction of the MJO and the EPO (eastern Pacific Oscillation) in cold phases.

In an interesting development today (and this could swing back the other way) the EURO EPS went from a positive early December phase Thursday, to a negative one Friday. Here's the reversal.

That puts it in the camp of the GFS which Friday had an EPO forecast that looked like this.

That makes me feel much better about the prospects of December cold (especially the first 10 days of the month). something I've been touting here recently. At least for now, both models are showing it. With that in mind, the EURO ensemble temperature departure forecast for days 10-15 (December 2nd-7th) came in this way.

The GEFS ensemble for the same period. It's even more widespread with the cold.

It's no wonder we see such a chilly trend with an upper air pattern at 500mb that looks like this December 3rd. There is going ti be a big cool down in early December but I'm still seeing conflicting signals if this is just a short term trend or one that sticks around the whole month. Some data shows the cold lifting out quickly after the 7th. I'll have more on where this is headed in coming days.

On the topic of winter cold. I thought this was interesting. Just 11 days ago the U.S. climate model the CFSv2, showed temperatures for the month of December at blow torch levels, similar to last year.

Thursday the upgraded outlook for December came in like this. Getting colder but still off the mark in my opinion.

Today the daily CFSv2 showed a big reversal as it indicated a 30 day December departure like this for the period Nov. 28-Dec. 28

Wow, that model got off the steroids in a big way! If that's not enough (if you trust it after that) it has this for departures the rest of meteorological winter. Actually I think the general idea has merit, just now sure if readings will be this extreme.



If the CFSv2 is on the right track a long cold winter would be ahead of us. On the other hand, this models track record leaves a lot to be desired.

So what about snow? The model does show precipitation December-February (0.50 to 1.5 inches) below normal. I'm sure the reason for that is the amount of cold air that's shown in the pattern. Cold air holds less moisture and the predominate NW flow would overall keep that to a minimum. However, snowfall could very well end up above normal with what precipitation occurs coming mainly in the form of white gold! I'm very intrigued to see how we fair out come March. Maybe another winter to remember!

That brings me to the potential snow system next Tuesday. The first thing that comes to mind in my area is that this is going to be a tough forecast with the rain sno