Carvers Gap

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Models looks really good at 12z. GEPS ensemble looks perfect. -NAO is showing up. Models are sensing that feature now. Always seems like it takes a few days to reflect effects at the mid latitudes once the NAO shows up on modeling.

Amazing. And then models should settle in a bit....they were all over the place today.

-NAO and -EPO on modeling are right there with the MJO. I don't think the MJO is related to the -NAO. The HLB in the medium and LR is textbook weak La Nina. The MJO is not without its exceptions as well. Kind of an interesting aside, I am pretty sure NC gets a lot of snow in phase 3...maybe one of the guys over there can comment on that. It also seems like that cold can come even if the MJO is in warmer phases during La Ninas - that is the exception but no without precedent. Again, have to be careful no to lean too much on one indicator, but it is also true that it has been a strong indicator during recent winters. I would argue the -QBO has equal or stronger correlation to cold winters. In fact, if this winter does not have a sharp cold shot, you might be able to count on one hand the number of times that happened with a falling -QBO - very few examples of that. Very much agree on the looping aspect. And also maybe @PowellVolzsaid this on another forum, but warm winters don't mean no snow. Sometimes warm winters can have a bit more snow due the storm track not being suppressed.

Good info. Yeah looks east based to me which is why the SER will likely fight all winter. That little ridge in TX is also a product of that on ensembles I think. Yes, the MJO is likely going to crawl. Looks like models have finally corrected for the tropical systems. We should now get a consistent progression with some loops(note crawling) embedded in that progression. The one good thing is if this can get into phases 8-1-2, it could be there a while and during the middle of winter at that.

edit: Actually not so much a dual block as a perfectly positions EPO ridge which is very similar to 17-18.

So the 12z GFS is how it is done...with one tiny problem. The air that gets sent southward from the Arctic is somehow warm! LOL. Normally, when one sees dual blocking send cold off the pole it is bitterly cold and well BN. This is like sending air out of the sub-tropic southward(some hyperbole intended). VERY UNLIKELY that occurs, but the look at 500 we take at this range in spades.

The other thing that is beginning to be a fairly significant feature on LR modeling is a well-placed -NAO. Now wouldn't be something to see a -NAO get us through phase 7, and then the MJO rotate in 8, 1, and 2. I do think dual blocking is now likely. So, the delivery mechanism is there to send very cold air into the Lower 48. But that SER is going to fight for every inch. Remember last winter when the cold made it to the Plateau and stop - THAT kind of fight. Now, I would guess the cold gets at least to the Apps this time, but with the sever cold holding to my west. But there are still a ton of uncertainties out there right now. Those uncertainties are whether the MJO can get into phase 8, location of the NAO block(trend is west), location of the Alaskan block, and whether the jet kinks just enough to allow cold to tuck under a big EPO ridge. I think the -QBO and cold fall argue for winter to push eastward. So, just could be a winter with some really wild swings coming up.

Last winter would be my example. D'Aleo does a great job discussing those tracks as does Cosgrove. Typical Nina tracks would cut west of the Apps and have sliders as primary tracks w/ secondary track along the coast which cuts through the Piedmont. Normally, tracks are rotten for the Carolinas unless on likes ice... Now, western Carolina can score BIG during Ninas and our TN communities in the Foothills can get upslope snow. But primaries are to the Ohio Valley, sliders along the mid-South, and secondary would be inland runners. Really, there is a good reason why many of our most memorable seasons are weak La Ninas. But....not sure what we are seeing on modeling is that traditional golden egg set-up....yet.

Surprised there hasn't been more talk about overnight model runs. Ensembles look good as do the operationals for the most part. 6z GFS even has Christmas Eve mood flakes for the higher elevations. As Mr Kevin noted yesterday, EPS has shown some good trends regarding the EPS and the -NAO. Looks like that continued overnight. Euro control is very cold and really locks in cold after the 21st. The GEFS and GEPS have a progression that makes a lot of sense, and would put into place a very cold pattern by the New Year. Still some things to sort out, but overall nice set of model runs overnight.

Ensembles look decent after just a quick glance. The 12z EPS is a bit of a shift west very late in the run, and centered over the Davis Straits which is textbook.

Thought this was a cool animation embedded in a Tweet by Webber. Found this in the MA forum. Looks very familiar to current modeling. The have another good post about the disconnect between the strat and troposphere which you can go see for yourselves. I hate just to grab all of it without sending folks to see that great thread.

Pretty interesting to also see that feature on the 0z CMC. 6z GFS is too progressive as usual, but is close. CMC actually has a great track, but a weak precip shield in the NW quadrant.

Not much to add this AM. Was good to see the Euro Weeklies and now the CFSv2 with a similar look. CFS now has a reasonable progression of its MJO. It is now the GEFS which is leading the way towards phase 8. Right now I am going to break down the wx pattern into 10 day blocks: Dec20-31st: Certainly appears that we get a couple of cold shots with warmth in between those transient thoughts. Real question is whether the cold holds after Christmas. For now, I think it warms back up briefly. Jan1-10th: Looks cold. Could always be a mirage, but certainly seems like the pattern will evolve to a least a temporarily cold pattern. Fits climatology. Fits with teleconnections. Fits with the MJO look. Fits with HLB. Jan10-20: HUGE question mark for me. I can see where a cold pattern would lock-in or simply leave and never return. If one looks at the analogs...84-85 is still in the there. December '92 is in there. Both of those had memorable events. @John1122, any other big winters in that group of analogs.

The 18z GEFS has a really impressive -NAO. Ensembles are now picking up those trends which is great.

I feel like I need to dust off my Tolkein concordance.

Oh, I think we are moving forward(famous last words I know). Just think about where things were ten days ago. The Euro Weeklies are money...if they are to be believed. I think once the tropics settle down in the MJO region, we will see a true orbit through the MJO. The MJO is moving, but the OLR is a wreck right now from what I have heard. The OLR is in turn creating issues with the MJO plot. Once those invests are out of the MJO region, I suspect modeling will reflect a similar pattern evolution found on the 12z CFS and today's Euro Weeklies. In other words, the pattern transition to cold might begin in very early January vs December. Some will say that is pushing back the pattern, and it might be, but IMHO it more like correcting an error with the MJO plot. Good to see so much blocking on LR models. That is a BIG change for the positive. As Jeff notes, just have to let a lot of this sort itself out.

Can you produce a Weeklies 500 gif? Thanks, man!

Yeah, I didn't know what anomaly he was referring to....if he was talking about La Nina's producing cold or just February being cold or what. For the record, extreme cold(though rare at this latitude)...if it is going to happen a weak La Nina is great bet. 84-85 have been showing up in analog packages of late. 95-96 is also similar. The cold snap of 17-18 comes to mind as well. NOT saying that will happen this winter, but saying a weak La Nina is going to be wall-to-wall warm is shaky, shaky ground. It can happen as it did during the late 90s, but man, they can go super cold as well. It is just a pattern of extremes. A pattern such as this has produced some forgettable warmth and memorable cold. But if we want a shot at wild weather, this is the pattern.

And indeed the Euro Weeklies are latching onto a pronounced -NAO and high latitude blocking scheme during the second week of January. Looks like the CFSv2 but without the initial cold shot that the CFS has. Good call...you called your shot on that earlier this afternoon about those changing. Also, great post. Models struggle with blocking. And totally agree about winter really not even starting for us yet. And yes, if we are having the same conversation about four weeks from now...different story! But anyway, Weeklies are now on board for better or worse.

It is literally what folks have been saying on this subforum here for 2-3 months. Glad those two could join the party.

I have no idea what that last sentence means.

Euro does well, because it has a warm bias. It is almost always the last to effectively model cold. When the pattern is warm, it does well. Of late the Euro Weeklies just basically have been wash, rinse, repeat of whatever the first two weeks are. Been pretty much useless. They and the EPS have not had realistic modeling during the past couple of months IMO - just total repeats of the first few days of each run. GEFS has not been much better. The Euro right now is to warm what the CFS is to cold - biased. That said if one knows the bias, they can still work with it. Still a good model. I could be wrong, but I don’t think the Weeklies will change...but who knows. Euro is not good IMBY until about January. Shoulder season for the Euro is tough. I much prefer the GFS and CMC are much preferred as they can see cold. Now, by Jan the Euro is the boss.

The Euro/EPS completely and totally whiffed on the trough after the 20th. It was the last on board. It is always safe to bet warm in the south though.

We know.