Carvers Gap

Been out finishing up some Christmas shopping. Modeling still looking good.

And that would make some since given what we are seeing in the LR.

Waiting for the MJO to roll right now. We may be looking at a pattern change, but more likely a relaxation of some sorts and full change later in January. However, what is on most modeling this morning is the first hints of the current pattern beginning to break down. WxBell still has the PNA negative on its run, but that is a PNA ridge that pops on the 6z GFS. Oddly, and I thought about this yesterday, but wasn't brave enough to post it. It is like the -NAO(which normally we want very strong) is causing a buckle which locks the cold out West, because it is in conjunction with the Aleutians high. When the NAO gets out of the way, it is like a dam breaking. That said, it does its work by forcing the cold south. Without it, the cold would slide across the northern border states. Not saying that is the gospel, but it did cross my mind. Reading through the MA forum which has a great winter thread going as well, they mention the NAO is more strongly correlated to eastern cold during mid and later winter.

The 6z GFS is nearly a pattern reversal to an eastern trough. The Euro control was nearly the same thing. Really good trends in modeling overnight. After reading John’s post, I agree. Looks like a 6 which is now moving to a 7. Have to think the typhoon was causing havoc last week.

0z ICON and CMC sneak a cold front through on the 29th. Worth noting, because that is different than what we have been seeing.

I think we can deal with the Aleutian ridge. It is actually common during many good La Nina winters. The GFS for the past 2-3 runs has shown it basically working to connect over the top with the NAO. If that occurs the TPV will be forced south into a broad trough between the Rockies and the Apps. I take the 0z GFS as is....that would likely be an overrunning event if real. Great discussion, everyone....

It was not as warm here today as I thought. Maybe I have seen all of these warm maps, and just got ahead of myself. Neighbor of mine had his fireplace going all day pretty much.

Definitely a lot of shoveling going on! LOL.

We will see if it is right, but the 18z GEFS is an outlier now among modeling...It may be leading the pack. Not sure.

Good point. This is the most recent update. What do you make of the third bulleted point in conjunction with Aleutians ridge? MJO indices continue to depict an enhanced West Pacific signal, and upper-level velocity potential anomalies show the enhanced phase crossing the central Pacific. The amplitude of the MJO has decreased, and the RMM-based MJO index depicts little eastward propagation over the past week due to interference from the La Niña base state and Rossby wave activity. The GEFS and ECMWF ensembles depict persistent enhancement over the West Pacific, with little to no eastward propagation. It is possible that this signal may reflect a temporary weakening of the La Niña atmospheric response. There is considerable uncertainty regarding the potential for this MJO event to remain coherent as it crosses the Pacific.

Reading reports in the SE forum of steady, frozen precip falling in western NC.

After 300, the Alaska ridge slides southwest into the GOA. Cold air jettisoned from the Arctic headed due south. Very cold pattern beginning around 282 for most of the Lower 48. Like a dam breaking that run.

18z GFS again moves the Aleutian ridge....this time it builds monster heights into Canada. Looks very much like the Canadian ensemble and maybe even the Euro control. Good trend continues.

The 18z GFS has the cold intrusion now on Jan 2nd. We will see if that holds during future runs.

And the GFS at 18z is back on the cold train. That is quite a cold look around Jan 3rd.

I am tempted to post the temp anomaly map for the Euro control at 360...super tempted. The entire US is much below normal. Looks like the Canadian ensemble, and 12z GFS. I lean warm, but barely warm in my thinking. I wouldn't be shocked for the overall high temp in January and low temp in January to have 80 degrees between them. All it is going to take is one strong cutter into the Plains....and it is going to get super cold here.

I think it worthy to discuss the warm solutions for sure, but ignoring the extreme cold solutions is probably unwise. It is worth remembering that the Jan 1-5 timeframe is still in the d10-15 range. It is also worth noting that the only ensemble model with 500 heights AN after 300 is the GEFS. Who knows where this goes, but that isn't exactly a warm set of ensembles after 300. Very possible(maybe even likely) they bust, but we can't ignore colder solutions of the 12z GFS, 12z Euro control, 12z GEPS, and I also thought the EPS looked decent after 300 as well(cold centered out West by bleeding west). I tend to agree with warmer solutions right now as trends support that. I keep saying this, but this reminds me of the run-up to last year's cold/snow event in the middle and western areas of the forum. With that blocking up top and the extreme cold in Canada, I expect the wild, wild swings in modeling to continue.

I very much agree on all points. I just don't understand that kind of talk(cancel winter and giving up) on Dec 22nd. I mean this winter could be a dud, but very unlikely with the cold sitting in Canada right now. We literally have the Canadian ensemble, the 12z GFS, and the Euro control showing Arctic outbreaks. There are some obvious models/runs which are totally the opposite. But there is a ton of model spread right now. I suspect we see a sever Arctic outbreak this winter but I could be wrong.

Euro control worth a look.... Word from an old timer. Webber, Cosgrove, and HM. Roll with those guys. I don't think folks sugar coat in this sub-forum. We just generally don't get overly worked up by a warm pattern. We are from the Upper South - just as slow roll. Cold is never really "pushed back" as it was never real in the first place. We are dealing with computer models which are at the mercy of programing and quality/quantity of data input. When looking at modeling, what we are trying to find is the reality of what will come. If given 25 outcomes, what we are trying to do is to find the one which makes the most sense and will close resemble future wx. So, things aren't really being pushed back or delayed. They just weren't real to begin with. But I do understand that we don't really have a better word/phrase for it. I use the term as well. Modeling is all over the place right now. The Euro control looked very much like the 12z GFS in terms of the surface temp result over the Lower 48. It didn't get there the same way, however. In fact, the control looks an awful lot like the Canadian. I mean it drops 6-12" of snow over the eastern half of the state late in the run. The entire forum area received snow with that slp.

12z GEFS and 12z GEPS are worlds apart. GEFS is warmer. GEPS is colder. The 12z GEPS looks like the 12z GFS.

Yeah, it may be gone next run as that is a major flip which leaves me very wary. Let's see if that looks gets a bit consistent over time....or not. Doubt we see that extreme each run...and that is extreme. But we can hope that is a hint that there is some restructuring about to occur up top. I haven't looked at the strat on that run, but guessing it is on fire.

Updated with better graphic....Here you go...12z compared to 6z...d10.5-15.5. This is 5d mean. The actual final outcome late in the run is far more impressive than this. I like using a 5d mean in order to show this isn't just a one or two day change. This was a wholesale change which means it is an outlier until it gets support. The Aleutian Ridge leaves and the cold heads SE. That is how you draw up an Arctic outbreak. Again, NOT SAYING this is going to happen, but it is always wise to pay attention when a model switches up like that.

That is a large scale shift after 240 - massive. That is what HLB can do in response to an uncooperative MJO.

Actually that couplet begins around the 280 mark. The destruction of the Aleutian Ridge begins about 240. This not just an evolution which begins past 300. Basically, the -NAO region retrogrades. The Pac Ridge connects, gets pulled eastward, and that is how you switch a pattern. NOT saying that is going to happen, but it is a potential. We all need to be rooting for that trend to continue!!!!

That would be a -AO/-NAO couplet on the 12z GFS. Doubt that is right, but there it is beginning around 300.