EasternLI

That's a solid winter pattern on the eps in the 10-15 day. 2nd half of the month looking very interesting. This is a 5 day mean.

For December, top 3 looks like it's been; #1 Euro #2 UK #3 Canadian

There actually is some cross polar flow into Canada on the eps. Starts building on the 14th. Looks -AO driven to me.

00Z same time period. Looking good.

Sure looks like its shaping up to be a very interesting 2nd half of winter.

End of the eps seems pretty phenomenal.

Schenectady smokeshow right now. https://wnyt.com/article/12543/

Solid moderate snow here with a coating on everything.

Light snow has commenced in Riverhead.

That euro run is about as good as it gets for a forum wide event. Let's do it. Lock that in.

LOL

I like ensemble means at this range. They all seem to strongly suggest a close to benchmark system. The 18z gfs looks well within the spread of the individuals of ensembles. The other operational models too, for that matter. Will be interesting to watch unfold.

That's one of the Singapore daily readings. Those are quite noisy from day to day. The graphic itself comes from the really nice NASA qbo page. https://acd-ext.gsfc.nasa.gov/Data_services/met/qbo/qbo.html

Agree with the warm IO. It's problematic. Exasperating the situation is the QBO this year it looks like. Being westerly, coupled with a la nina, it's just not an ideal situation. All of these things combined looks to keep forcing "trapped" in the IO for the most part. It's why the euro weeklies have been showing the awful pattern moving forward. (Yes, the weeklies have been abysmal at times. The problem is, there's research to support them in this case.) Combined effect of the QBO and ENSO on the MJO https://www.tandfonline.com/doi/full/10.1080/16742834.2019.1588064 The QBOW phase, however, will suppress the MJO intensity over the Maritime Continent through enhancing the diurnal cycle; plus, there is no reinforcement of the MJO over the western Pacific because of the cold central Pacific of La Niña. Thus, the MJO rarely reaches the western Pacific during the La Niña/QBOW phase (Figure 3(d)).

Nice post. It could be a part of a Vortex Intensification event (VI) as is described in the following paper. If so, would be terrible news for any -AO prospects. Here's a couple of relevant quotes from the paper. The life cycle of such events, if that's what is indeed occurring, can be up to 80 days. Stratosphere‐troposphere evolution during polar vortex intensification https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JD006302 Reduced poleward planetary wave heat flux occurs as the circumpolar wind becomes strongest and pressure anomalies penetrate toward the surface. Descending pressure patterns project strongly onto the positive state of the Northern Hemisphere Annular Mode (NAM). Between days −20 to +20, reduced poleward heat flux is observed as the vortex becomes strongest; increased poleward heat flux is observed as the vortex recovers. [41] In our preliminary examination, the anomalous vortex intensification seems to occur preferentially during La Niña conditions.

It's a great question. I'm quite sure the answers are much more complicated than what my current understanding is. I am aware of a few things though. I don't have the data to back this up right now, but there is some relationship with the Indian Ocean and ENSO. Through Ocean current and rossby waves also I believe. Not sure about the Atlantic. I haven't seen anything about a relationship there. Why is it important in regards to the NAO? Mainly, because forcing there strengthens the PV, as it pertains to this year specifically. The following paper describes why that is an issue. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL084683 The state of the stratospheric polar vortex has a clear impact on the NAE (Scaife et al., 2005) weather regimes (Charlton‐Perez et al., 2018). NAO− is most sensitive to this stratospheric state, occurring on 33% of days following weak vortex conditions but on only 5% of days following strong vortex conditions The same paper also goes into what to look for if we're hoping for an increased opportunity for some -NAO. As it relates to MJO activity combined with different ENSO states, La Niña for this year. Naturally, other factors are always at work as well to determine what the end result is. In any event, it would seem that we would really like to see the MJO be active through phases 7+8. We find that the MJO–polar vortex–NAE pathway is strongly active during La Niña years (Figure 3c), particularly for the weakened vortex following MJO phases 8 (corresponding to the third pentad after phases 6–7 in Figure 2), associated with the low in the northwest Pacific following MJO phase 7, increasing vertical heat flux to the stratosphere. There is also a weakened vortex closely following MJO phases 7–8 during neutral years. These contribute to the increased NAO− occurrence around phases 7–8 during neutral and La Niña years (Figure 1).

Published: 12 November 2020 An earth system model shows self-sustained melting of permafrost even if all man-made GHG emissions stop in 2020 https://www.nature.com/articles/s41598-020-75481-z In this paper we report that in the ESCIMO climate model the world is already past a point-of-no-return for global warming. In ESCIMO we observe self-sustained melting of the permafrost for hundreds of years, even if global society stops all emissions of man-made GHGs immediately.

A potential for a shift away from the IO down the road a bit. Maybe. Could shakeup things a bit hopefully.

As far as I can tell, there just wasn't that much research on global effects in the past. There was a lot of research on more localized effects. It's gaining more attention more recently though. Probably because it's identified as an area with anomalous warming trends.

As was brought up earlier in this thread, research says Indian ocean convection will strengthen the PV. The following 2 tweets are related. You can see anomalous negative VP in the Indian ocean first. Signaling anomalous convection. Secondly, the strengthening PV. Quite impressively actually.

Nice outlook Isotherm. I think it's even more optimistic than what I was thinking. Hopefully it verifies.

Some great points. Makes a lot of sense. Perhaps a good cautionary tale of using any older analog years. The arctic sea ice issue is interesting. Something I would like to do some more reading on. I think it's one area that is gaining popularity in research. The QBO has had a good amount of attention recently.

Oh I am in full agreement on your point here. My post was in reference to the tropical pacific warm pool. Which can drive a favorable winter pattern for us. Instead, the models are locked in on the Indian ocean. Which can drive a terrible winter pattern for us. But the current state of the QBO gives support to what the models are showing IRT that. As far as the North Pacific warm pool. My thinking is that it's more of a indicator of what the pattern had been. Not necessarily a driver of much. Maybe more of a modulator? I just feel like those anomalies can be bullied around by what the tropics are doing as that is where the most energy (heat) resides. I feel like this winter is going below average snow maybe way below, much above average temp. Not seeing much for winter fans to be excited about TBH.

Thanks. There's certainly a risk of a very warm winter ahead. I'm not overly fond of anything that I'm seeing at this time. The Pacific warm pool (associated with the PMM) could help us out, but will it? That's one area of very warm water. The other is the Indian ocean, which is what models are keying on right now. Interestingly, the MJO to -NAO connection is strongest in La Niña years. https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL084683 The NAO− regime teleconnection via the stratosphere from MJO phases 7–8 is most enhanced and occurring latest during La Niña years, while it is suppressed during El Niño years. Unfortunately, it seems that the QBO is working against us here being westerly. Suppressing convection where we would prefer to have it. https://journals.ametsoc.org/mwr/article/147/1/389/103189 As MJO events propagate eastward over the MC during boreal winter, static stability anomalies increase in magnitude over the eastern MC and WP. That is, static stability anomalies decrease during QBOEM and increase during QBOWM, corresponding to a less stable atmosphere and increased RMM amplitudes over the eastern MC and WP (RMM phases 5 and 6) during QBOEM, and a more stable atmosphere and decreased RMM amplitudes over the same region during QBOWM.