EasternLI

Just looking through modeling trends and thinking about this again today...

Yeah, just wouldn't be surprised to see changes happen a couple or few days before the 15th is all I'm saying. Nothing crazy. That is a good point about the vortex too. Absolutely.

Yeah nice video from him. Brought up some of what I posted about on Saturday. I'm a little quicker with the process though. Don't need convection at the dateline for things to happen. It's well underway before that. Still think a +PNA is a very real possibility though too. But same general idea. Pacific jet fires off and these waves break. I think the 00z EPS is still suggesting that the whole process gets underway too TBH.

There's a shakeup for the Pacific in the pipeline as we start getting into January. I think this could offer an opportunity for a period of +PNA after the 1st week when these waves break but we'll see. Maybe this ties into Ray's @40/70 Benchmark ideas mid-month so maybe it's part of that timing to transition to +TNH. But I think sometime week 2 we see some changes and maybe clues to that happening during the 1st week of the month. We're being plagued with a series of -EAMT retracting the Pac jet and locking the Pacific block in place on guidance in perpetuity. High pressure into the west of the Himalayas removes the momentum. While high pressure on the east side would add it. This is likely going to change as we start heading into January. An active convective phase looks to cross an Indian Ocean to MC transit to close out December. These set in motion a series of events that eventually leads to +EAMT and a Pacific jet extension. Even at the end of the current EPS 12z I think we can see some signs of a changing Pacific regime. With high pressure building in Siberia in better position and a Jet beginning to be reinvigorated off the coast of Asia.

Regardless of what happens with this blocking potential. I think there's a pretty good chance of popping a +PNA after that first week of January. Via Pacific wave break. I can make a longer post about that tomorrow.

Doubt anyone anywhere sees much of any NAO blocking, unless an actual Scandinavian block happens first. The open ridges rolling over won't work for anyone. Including Europe. Models and ensembles still all over the place with that too. And that's something starting towards day 7 at this point. Need it to happen...

Might be doable. Previous runs had that ridge centered more in Iowa. It's already ticked west a little bit. Maybe that continues.

Still trending on the 00z.

Trending towards the powerhouse Scandinavian block scenario in that 8-10 range on the EPS. As a consequence of that, it's also trending towards a powerhouse Greenland block scenario arriving in the longer range 11-15 day clusters.

Damn who screwed up your breakfast order... happy holidays to you too I'll take the under on 50's after Friday. Seeing a lot of lows in the 20's though.

Can we please make this a thing. Thanks.

This run is vastly different from all the previous gefs runs along the eastern seaboard.

Personally, I'm thinking this 8-10 day range here is pretty meaningful. Does Santa deliver a true Scandinavian block or not. Some of these half attempts probably don't work well for us. This is from the 12z eps cluster analysis. 5 of them for this period today. Todays Euro OP says no, and is grouped with cluster 2. Cluster 1 on the eps, populated with a greater number of members says yes. I flipped this for easier viewing of our side of the world. So clusters 1-5 is left to right. Days 8-10 are bottom to top. If we do happen to see an amplified block like the 1st cluster is displaying then you'd probably see a pretty big wave 2 shot that goes up into the strat along with it. If that does not happen, then you won't see that. Probably not a retrograde to a true -NAO block either I would assume. You can see it expressed in the EPS strat mean during this timeframe too. Which is most likely reflecting that potential feature in the members. One way or another, we want to see that block happen. Incidentally, there are factors which support the block to indeed happen based on reasons laid out in this thread already. We wait and see if one does actually materialize but it does appear as a favored outcome in this 12z eps run as well.

Two clusters on eps cluster analysis in the long range last night. -NAO of unknown impact the general idea. There is a road in some analogs where we start January with a -NAO and as we lose that, the PNA goes positive. Could we take that road this year?

I've been optimistic and I remain optimistic for this winter as a whole. Look warmth is by far and away the favorite to win out as we move through future decades. That's reality. We aren't all the way there yet either though. Some still get blown away seeing very impressive warm records when they occur. Which is fine. To me, that's to be expected more and more in the future during warm patterns anyway. Cold is more exciting and tends to bring exciting weather especially in winter. Plus I enjoy rooting for underdogs! Yet at the same time I'm going to be honest. Being disingenuous is stupid and makes no sense to me in any facet of life. This year feels like it's acting quite different than the recent ratters we've had. Sure there's a mild pattern set to visit for a time. That's legit, as discussed. IMO it's probably something like 1 week, maybe 2 tops. And new england might not even see very much of that. But this is starting to look more and more like the old classic Scandinavian Block > -NAO sequencing. Do note there is a mild period included during the beginning of that process.

How have the AI Ens been doing? I haven't been following too closely. Some suggestion on them that the pacific trough would retrograde further out into the GOA. With subsequent increasing heights in the PNA region. If you loop them.

Snow is falling here. We'll see what we end up with.

18z Euro

18Z RRFS

Yeah, HRRR gone wild. And still going lol.

Soundings aren't looking half bad... When the lift comes through it's smack in the DGZ. Should see a pretty good shot of snow growth with this. Not really seeing any dry layers to eat it up. That's on the nam. If the RRFS were to verify, would put my area right near average snow for the entire month of December. Something that hasn't happened here since winter 20-21.

Check out what the top 2 clusters (left 1 to right 2) from this run end up with by the end of that same period...

Well sure, a couple things about that though. I've seen those charts change very rapidly in the past for one. As they start picking up on any specific tropospheric pattern that are the drivers of said events. Which models aren't great with at extended leads as we all know. Or even 5 days for that matter . Also that chart is from yesterday's weekly run. I didn't see anything resembling what I posted about on any of the runs yesterday. This was something new today in the 00z eps members. Lastly, I didn't call for anything to happen. That was just perfect opportunity to bring it up as it's a good illustration. Plus seeing that within the 00z eps members is a little interesting.

Hmm, this is an interesting chart depicted by last night's eps cluster analysis. Not for whatever it may be depicting in anyone's backyard. The leading cluster in the day 11-15 range is this one. That progression of the troposphere gets really close to something resembling EOF2 from the following paper. With the +NAO and Scandinavian block. The progression leading to it is even pretty close to what is depicted in the paper. The Scandinavian Greenland dipole. Worth keeping an eye out for that phenomenon in future runs. As it's not something that's well modeled in advance. But a depiction of something like that on a prominent piece of guidance is interesting. Representation of the Scandinavia–Greenland pattern and its relationship with the polar vortex in S2S forecast models https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.3892 From the abstract: "The strength of the stratospheric polar vortex is a key contributor to subseasonal prediction during boreal winter. Anomalously weak polar vortex events can be induced by enhanced vertically propagating Rossby waves from the troposphere, driven by blocking and wave breaking. Here, we analyse a tropospheric pattern—the Scandinavia–Greenland (S–G) pattern—associated with both processes. The S–G pattern is defined as the second empirical orthogonal function (EOF) of mean sea-level pressure in the northeast Atlantic. The first EOF is a zonal pattern resembling the North Atlantic Oscillation. We show that the S–G pattern is associated with a transient amplification of planetary wavenumber 2 and meridional eddy heat flux, followed by the onset of a weakened polar vortex, which persists for the next two months."

Yeah, this warm pool facet of how things are evolving this year is pretty fascinating. Eric Webb had even made a mention of this idea near the beginning of the month too. I mean... we legitimately could be attempting to pull off something exactly like that... Already, over the last 7 days there's been warming and cooling of sst's in all of the right places (1st image). Plus with an outlook favoring some persistent wwb's right around the dateline (2nd image). In the near future and for the seemingly foreseeable future. With that warm pool currently leaning a little to the east already too. Sure sounds a lot like the proper recipe for continuing to see good things evolve out there in the wpac.