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When Allen posts I listen. @RaleighWx · 1h The 12z EPS shows the 10mb zonal wind at 65N is approaching a reverse to easterly late in the extended. This COULD harbor continued/enhanced blocking in the high latitudes in the troposphere as we head deeper into January. Image from http://stormivstawxmodels.com

Regime ensembles paint a pretty picture for January regarding a favorable - NAO Blocking signature and location. @SimonLeeWx · 1h In terms of the surface response to this weak vortex, it is too soon to say anything substantial - but note that the regime of the ensemble-mean is the negative NAO for the middle third of January, with Greenland blocking prevailing...

A player for sure ....maybe Jan 3 rd to the 14 th. Eric Webb @webberweather The 12z full res ECMWF is going w/ absolute min temps as low as -60F in southern Russia as a 1069 hPa sfc high descends into Mongolia. Oof 2:03 PM · Dec 21, 2020·Twitter Web App

To me the Euro took a step back. Its active but not cold enough. Hard to say what will transpire. Not worth the time to think it over, hopefully after the 25th its clearer. By that time wave breaking will be working it's way through the modeling and a more realistic outcome will present itself, whether it is more rain or snow.

Hopefully it does bode well for January. I am wondering whether any effects from say a relocation of the PV , displacement event, PV elongation, etc. may get us into a improved source region without depending on a -EPO. Total speculation here but there are some interesting animation regarding the NH PV and how it evolves over the next 15 days. Here are some still images of the forecasted GFS NH polar vortex ellipse. Also a great reference site : https://stratobserve.com/

The consistency and the depth portrayed regarding the - AO and the - NAO for the rest of this month and the first week of January are really stunning. Added to this is the ongoing warming up top and you have to really wonder what we may achieve at the lowest point of the - AO phase. This is pretty crazy looking.

Impressive London & Southeast @TheSnowDreamer *Huge* heat flux now being modelled by ECM goodnight vienna stratospheric polar vortex. 3:16 AM · Dec 21, 2020

Very true and yes folks require the digital fix. Looking at the next 10 days there appears to be two robust Atlantic wave breaking events. Perhaps the Atlantic blocking is underplayed currently despite the great looks by the models. Maybe the block will be even stronger than modeled. I expect medium range changes moving forward.

Just like last year, typical climo. Sigificance is when the mean is 6 or more inches. Then let the dogs out.

Certainly some of the looks that we saw back in the winter of 09 10 were incredible. I would never reference since xxxx.

Beyond the physics of the GFS to handle that mega block. I would not trust the Euro either just yet. Although I would think the EPS mean snowfall should be above climo, we shall see later .

Even with blocking it is fair to say that expectations should be tempered. But, wow, night and day versus last year at this time.

Is the blocking more West based ? Can you share an image?

Again not sure SSTs in NW Atlantic are responsible. I recall Blue Wave in the New York Forum doing a post back in the late summer where he mentioned the SST pattern over the Northwest Atlantic was responsible for the Western Atlantic Ridge being displaced further north this year versus further south . Wondering if it is still a factor. Is it at Play here again here with the Greenland block.

Well, psu made a great post on that. You can search for it, but we have our friend the - AO to help us. At least we are in the game after the 25 th.

When looking at the PNA domain it is possible things improve there, a short window with a more pronounced +PNA will help the storm threat window(s). I have not checked today, but yesterday it appeared the PNA was headed more positive and the NAO more negative.

For once I can say that is starting to look better. Models are still catching on to the blocking scenario and eventual outcomes at the lower latitudes. Also, I have not seen this blocking signature for some time, evident by the temp anomalies to our far NE via the Canadian 10 day mean.

Highest heights are not in our favored area, looks like a East based Greenland block. We need that block to retro West into the Davis Straights. That could be one reason, but not the only one.

Also pondering data sparse regions with some of these Northern disturbances and last minute model swings. HM did mention if blocking develops robustly as the models indicate it could lead to interesting low latitude winter storm analogs.

OP at range, but it's almost the exact same location as the last of debacle. Really looking to achieve offshore ideal track, hopefully upstream blocking will shake things up. Also this regarding the 25th. Ethan Sacoransky @blizzardof96 · 8m Model guidance will continue to struggle with the #Christmas system. The storm energy is currently located over a data sparse region of the north pacific & is embedded within a broad/complex jet streak. The energy is incident on the west coast by Monday evening.

Impressive !

Looking good as we near the end of December and early January.

Today 1/3 of the CFS members go for dramatic weakening, ( zonal wind reversal ) but the look in general is a weakening PV over time in two phases. Early January may feature a deep- AO dive in my opinion and a significant storm threat.

A few more members yesterday jumped to the dramatic weakening

Clever insert there