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"Overall we have it the coldest and snowiest in 5 years with an exciting Winter if you like bigger snow storms from the Heartland to the Middle Atlantic/East Coast."
[thread] Starting point for this winter, examine the ENSO conditions. From Jin Yi Yu 2012 we can identify CP Nino's 1950-2012, assuming this yr's Nino is largely CP, composite when plotted for DJF:
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Now let's take a look at the same years for OND, for more current conditions, you can see, we have some issues. let's examine in the next tweet.
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The big issues are:
1. Atlantic is FAR to cold in the Analog composite off the ECoast
2. NPAC is also way to cold in the Analog's, and the PNA Region is opposite
3. Waters off the SAMER Coast are warmer in the analogs
But that does not mean ALL the analogs are bad in the set....
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Separating all the years, we come up w/ Analog and Anti Log list:
Analogs:
2009
2004
2002
1991
1987
1958
1957
Antilogs:
1994
1977
1968
1965
1963
1953
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The Analogs get us to something like this:
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Compare it to current SST's:
1. Atlantic is fairly good, although a bit cold off NF, however Central ATL good.
2. PNA Region a bit colder than the analogs - but I presume we will see that change in the coming wks with ridging
3. WPAC cold in the analogs
4. Indian Ocean good
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Under these assumptions, if we roll this forward to DJFM we get to something like this:
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Some final thoughts: This package is not my #1 pick, I will say. It only takes into account ENSO conditions, which for this year is not the way to go. I show this to illustrate what it can give. Next we will do the same for the PDO/AMO, and finally one to combine ENSO/PDO/AMO/etc
Probably not going to happen, especially with the way the weather has been as of late, and, since the AMO is going negative now, I suppose you can kiss those mild winter seasons goodbye.
The Arctic Oscillation (AO) is currently slightly positive and is predicted to remain positive this week and then trend negative next week possibly into negative territory to end the month.
The current slightly positive AO is reflective of mostly negative pressure/geopotential height anomalies across the Arctic and mixed pressure/geopotential height anomalies across the mid-latitudes. The North Atlantic Oscillation (NAO) is currently positive with negative pressure/geopotential height anomalies across Greenland and Iceland and is predicted to remain positive this week and then trend negative next week.
Currently troughing/negative geopotential height anomalies are confined to Western Europe including the United Kingdom (UK) with ridging/positive geopotential height anomalies dominating much of the rest of Europe centered on Northern Europe. Currently below normal temperatures are confined to far Western Europe including the UK with above normal temperatures widespread across the rest of Europe. However predicted deepening troughing for much of Europe will lead to a cooling trend over the next two weeks.
Asia is currently dominated by an omega block pattern with troughing/negative geopotential height anomalies in Western and Eastern Asia and below normal temperatures and ridging/positive geopotential height anomalies and above normal temperatures in Central Asia. Over the next two weeks ridging/positive geopotential height anomalies and above normal temperatures will become more widespread including the Middle East with troughing/negative geopotential height anomalies and normal to below normal temperatures confined to far East Asia.
Currently troughing/negative geopotential height anomalies with normal to below normal temperatures dominate much of western North America with ridging/positive geopotential height anomalies and above normal temperatures dominating eastern North America. However during the week the pattern is predicted to transition to troughing/negative geopotential height anomalies with normal to below normal temperatures in eastern North America with ridging/positive geopotential height anomalies and above normal temperatures in western North America.
I discuss in the Impacts section some global climate model (GCM) forecasts in the context of ENSO and Arctic sea ice.
I try to maintain independent thought when anticipating long term changes to the weather and therefore try not to pay too much attention to the numerical models. The models have their strengths and weaknesses but I do think that I provide the most optimal service when my forecast is independent from the models whether it agrees or disagrees with the model forecast. An example from last winter was in early February when the significant polar vortex (PV) was just beginning and simultaneously a strong Madden Julian Oscillation (MJO) phase 7 and 8 was occurring. I think I was at my best when I disagreed with the models initially predicting mild in the Eastern United States (US) followed by colder and possibly stormier weather which was opposite of model forecasts. However I do believe that knowledge of the model forecasts introduced uncertainty into my thinking.
With that caveat of the benefit of ignoring model forecasts, I present what is I believe is the latest European Centre for Medium Range Weather Forecasts (ECMWF) winter forecast in Figure i taken from climate.copernicus.eu. The ECMWF model is generally considered the best forecast model on the planet. The first thing that jumps out at me is the predicted classic or text book positive Pacific North American (PNA) pattern with a deep Aleutian Low, ridging or elevated heights across northwestern North America including Alaska and troughing or low heights in the Southeastern US.
The ECMWF model is also predicting a quasi-negative NAO with the southern pole or center of action more classically represented than the northern pole. But in regards to the US winter this represents a suppressed storm track along the Eastern Seaboard.
A positive PNA should yield an overall cold winter to the Eastern US. The ECMWF model is most confident in a relatively cold winter in the Southeastern US with greater uncertainty in the Northeastern US while the suppressed storm track will bring elevated risks of East Coast snowstorms. And El Niño does tend to focus the greatest snow threat, at least relative to normal, in the Mid-Atlantic. If you are a winter weather enthusiast especially a snow lover living in the Mid-Atlantic this ECMWF winter forecast should have you very excited.
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