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Agree here, good point. This may be setting up the two different outcomes.

Can't deny the STJ so far this season........... eventually you have to think they time up correctly for us.

This period has shown interest. The vortex continues to get pressured, zonal winds are forecast to decrease as well , No SSWE on the table, more so the vortex displacements/elongations. IMHO still feel the key to getting sustained cold and snow threats is going to be the improvements in the Pac. As psu alluded to we don't require a stellar Pac later in the season, but we do need deep cold air sources and help from the NAO domain. If the Pac will not cooperate we will indeed need the - NAO domain to deliver. I like to see some really cold air build up in Canada and an improvement in storm tracks allowing us the potential for over running events. Last winter if you recall the storm tracks many times were cutters and inland runner. Let us see if we can reshuffle the cards after the warm up .

Regarding the - EPO once more ........

Snow that hangs around a bit would be cool! Also, an interesting look - like a 1960s-ish which @psuhoffman posted a while back. In those blocking winters of the 1960s winters really ramp up after the 1 st of the year. Plus, the look you posted Bob tends to fit the blocking signature in the Atlantic you find in some of the low solar min periods.

For once it would be nice for the CFSv2 to verify. Analog-wise this forecast does have some support.

In regards to the EPS we have seen it miss the -EPO previously this Fall. I recall one such event. Different ballgame this go around, but Webb states the EPS does not have a good track record with seeing the early signs of a -EPO event at times. Read that over at 33. But, BAMWX has also brought this up previously as well.

I propose the bias of both models in regards to the ensuing pattern change. The GEFS rushing things while the EPS taking too long. Ninja by WxUSAF

This makes sense. Hope it progresses. Also of interest regarding the SER

Webb believes this will happen and expects the models to go to this outcome. In play are model biases and such. He believes the progression is brought about by a combination of wave breaking and an improving Pac / tropical forcing regime, in part due to the weakening +IOD Speculating myself if maybe some sort of - EPO delivery of intense cold is going to get trapped under a block in early to mid Jan. leading to a threat window ( over-running/ clipper / colder version Miller B , etc. )

One final note about the + IOD decay. Echoes the thoughts above.

Will get more data soon but the +IOD is weakening. Really feeling this is a potential game changer. It was more than likely the # 1 pattern driver. It also causes an acceleration of the jet and interferes with ideal West Pac forcing. That looks to be slowly changing. The various modeling weakens the + IOD , but not to below the threshold value until Feb 2020 with universal agreement to below 0.4 C occurring in March 2020 I am hopeful either the weakening is more rapid, or the + IOD weakens enough to allow a more favorable West Pac regime to unfold sooner. http://www.bom.gov.au/climate/model-summary/#tabs=Indian-Ocean&region=NINO34 Indian Ocean Dipole (IOD) outlook Sea surface temperatures in the Indian Ocean have shown patterns consistent with a positive IOD event since the end of May, with the IOD index exceeding the positive IOD threshold from mid-July. The event peaked in mid-October with a weekly index value of +2.2 °C. Despite recent weakening, the latest value (for the week ending 8 December) is +0.9 °C, persisting above the +0.4 °C threshold for the 19th consecutive week. Most models suggest positive IOD index values are unlikely to return to neutral until January or February. This is much later than would typically be expected with an IOD event, and is due to the delayed transition of the monsoon trough into the southern hemisphere. This transition typically happens in early December, heralding the imminent decay of any active IOD event, but has yet to be observed in 2019.

Saw that this morning. Some interesting things going on up top, can almost see an evolution similar to November happening in Jan at some point. Ural block nice to see . Some serious cold may come over the top in Jan., similar to November. Another -NAM state accompanied by an improving Pac would be most welcomed. Looking like the table resets in Siberia and then the move is on.

If the ECM is correct regarding the MJO progression it will take some time to flip colder again, as others have mentioned here. However, this certainly does not look like some of the craziness depicted last year at this time when we started to warm up and the MJO phases were all warm, and at a high amplitude. Not to mention, the movement in those warm phases was VERY slow. From bluewave : << Next few days should be our last Arctic air mass for a while. The MJO forecast to move near phase 6 means mostly a mild Pacific influence into the longer range. >>

If this goes down again could be a plus for us. Bringing this up not because of the potential of this leading to a SSWE, ( which again I put at low odds ) but more so the benefit of anticyclonic wave breaking, etc.

They were persistent last year when predicting a cold and epic pattern, we know how that turned out, maybe they are more accurate in a warmer climate, LOL. I do think the 1960's analogs are intriguing. On a brightener note, there are some positive changes taking place. + IOD weakening, but slowly, and some hints that the vortex gets pressured again. No SSWE in sight, and if one were to occur at all this season I place my bet on Feb, or even March. Really believe the fate of significant and sustained winter period(s) is going to ride on the weakening + IOD and more robust and favorable MJO phase(s) and progressions. Also, need to achieve and maintain some sort of -AO and intervals of +PNA. Seeing the deep cold air and snow depth increases once again being modeled over Siberia is a plus for Jan. Maybe Jan evolves similar to November but a week behind and in our peak climo. The biggest tip off today might be the better trends of the AO for the second half of the month and at least not a horrible PNA. moving to neutral at least.

Good luck out there tonight !

Even though we have not had any significant snowfall in the Dc and Baltimore areas so far, it does seem the HL have been friendly and any vortex elongations , at least cold air delivery-wise have benefited the NE part of the country, including us. I hope that continues.

Good point about sources. I know various models have different ideas about the MJO progression. Some on the colder side, other warmer. I believe the ECM depiction might be the warmer phase(s). Meanwhile we have a vortex strengthening event taking place. The vortex normally fluctuates in strength, and I believe this is the time of the year when it is the strongest. I still prefer it to be weaker honestly. Also, the precursor pattern pattern that weakened it after the last ramp up , well, I am not so sure we get a healthy attack going on any time soon. I hear things, but nothing very firm. The seasonal models, as I know, called for the vortex to be on the stronger side and remain so, however that does not mean a weakening vortex can not happen in Jan. Even a SSWE can still occur later in the season, including vortex elongations, and displacement events. A lot to keep up with.

As mentioned previously, a few mets believe the +IOD will weaken. Actually, it has started to weaken, hopefully that trend continues and the caveat is the lag period needed to wash out the residual atmospheric effects of the record + IOD takes some time. I have not heard anyone yet venturing an estimate on when that will be.

If correct, will be interesting tracking that serious cold for mid Jan.

Just looked at some composites, very interesting psu. Hopefully, an eventual Pac transition occurs sooner versus later. Just reflecting, but maybe the Pac puke was due, considering the duration that we had a decent Pac . Granted, the Atlantic muted the recent, no as good Pac, as evident by the warmer December temps out West. Maybe the Pac nasty period is simply the Jan thaw two to three weeks early. My positive side says, I hope so. Not sure that fits though with the other indices in fantasy land. A very volatile period indeed.

Bob, as you stated, not the first time the Pac has ruined everything for us and others, even with a favorable Atlantic. And, as stated several times in the past, the Pac jet has been a long- term concern, as has the inability to achieve a +PNA pattern and improved longer lasting ridging out .Some of the same issues as last winter. Even Tip mentioned in the NE forum a couple days ago, that we ( more so his region, but I find that concerning because they are at a higher latitude and in better climo too ) really need a -EPO cold air delivery and intervals of +PNA. He stated issues regarding the lack of cold air delivery and entrenchment. I found Tip's points right on the mark. I also think back to bluewave's posts, over the past three months, and how the configuration of the Central Pac SST profile supports the ridge further West this year, like last year, and this also eventually could lead to a SE ridge feedback. We need warmer SSTs up against the West Coast.

Ralph, I didn't say I was punting all of Jan. I merely stated that even if the pattern is not so great for a majority of the upcoming winter ( speculation ) all you need is a decent winter like period of say, several weeks, with multiple snows to mentally check off the winter as a decent one. It really is all about perceptions at times. No doom and gloom was intended.

A great period of winter weather from Jan 23 to Feb 25 would make this winter a winner. Still feel it delivers, but as you know, this upcoming winter has always been referred to as one with conflicting signals. regardless, no one should panic now even if the warm up lasts a while.