Stormchaserchuck1

https://ibb.co/BtJGb7J March 2018 was the last time we saw -NAO-based trough in the East in the Winter months.

I've been telling everyone "not through Jan 15th" (more realistically looks like through the 20th, then we'll probably change).

In 7 days it posts a big Aleutian ridge. This has been overwhelming the NAO just constantly since 2018-19

These setups don't trend favorably inside 7 days. We would need a big Pacific pattern change.

I don't see this being snow at all in verification https://ibb.co/gTZh53c Pattern is building from the Pacific. looks like the GFS gets luckily with the timing but you see there is a 2nd low developing to the west of the system.

12z Euro actually shows us getting some flurries Monday with a clipper. That's what I'm most excited about. Cool pics guys!

Good post Don. Not many examples, but -PDO/El Nino December's are very close to verification for the month: https://ibb.co/yfBVPXY https://ibb.co/tmFPSmv January of the 4 analogs I came up with: https://ibb.co/2nnqHrG https://ibb.co/sR01NT1 Talk about getting it coincidentally right for half of the Winter!

We have had an anomalous global pattern since 1998. As you can see below, the -PNA (North Pacific ridge), has recently exceed global warming and appears as an anomalous area in the Hemisphere: https://ibb.co/2csFL89 Because we have had a N. Pacific Ocean ridge, many have identified the waters effected as "-PDO", because they are measured based on cyclical moves over long periods. However, if you look at the whole globe, you will see that the area effected in the N. Hemisphere where the Hadley Cell and Mid-latitude Cell meet is the same place as in the S. Hemisphere where the Mid-latitude Cell and Hadley Cell meet: https://ibb.co/yRGTTHn Based on that, you would say forcing is not coming from a body of water in the N. Pacific ocean, but the equator, and more specifically the Nino 3.4 region where variations have been known to make big global impacts. So in the last 25 years, I separated years by ENSO event and Neutral, and found that we are seeing a La Nina base state in both conditions: ENSO analogs: https://ibb.co/V9yfKh2 Neutral ENSO: https://ibb.co/g7ffp52 The Hadley/mid-latitude cell meet is still there on both composites, but it expands both north and south in the Northern and Southern Hemisphere on the Neutral ENSO years. I think that instead of identifying this period as -PDO phase, we should call it more of a La Nina phase (98-23). Basically, when ENSO is Neutral we are still getting an equilateral La Nina base state.

Stratosphere warming is happening https://ibb.co/MRc03C6 That was basically my theorem, that El Nino and -QBO would give us good snowfall/cold Winter periods. I don't see why that can't be achieved. -PNA is pesky but it might change at the coldest Winter time, and our precip has been well above avg since the Summer: https://ibb.co/r5k2sc6 It might also help to keep up with Natural Gas price, Lots of things are happening that we don't know about.

I'm more worried about the cold air flow. but I guess this is closer, problem with the first system is lack of High pressure to the north, or 998mb low in SE Canada. 2nd storm has a Aleutian ridge already building so this starts to pump a SE ridge in the 500mb pattern. In my experience those two factors trend less favorable as we move toward the actual storm getting closer (lack of cold air needed)(rain), but the system could amplify. To trend better, The El Nino may start effecting the pattern in trend? I think it's 90/10 these will be rainstorms in verification.

Yeah, I don't think this is because it's an east or west-based Nino https://ibb.co/yQxk7bS

Do you think that models like the EPS are too programmed for it? In researching, I found that Stratosphere warmings in 10mb never exceeded +2500, and we are already at +1600 as of 12/27

I'm not one to give up on snow. It seems like a lot more precipitation is happening, and the possibility for stronger storms. I always thought 09-10 was a step in this direction. You see how on the coast the trend is actually upward. I think the -PNA is the real problem, and that even held in a lot of the early 2000s when we were doing well with snowfall. https://ibb.co/2csFL89 As the pattern relaxes, low's are energized not inland, but off the coast over the water, and the early 2000s were filled with examples of this, where they would track just right off the coast. I don't see that trend as disappearing, I just think it has been a very -PNA for 7 years. In the later part of a -PNA cycle, SE ridges are more dominant.

Why? Most El Nino's have a nasty +PNA by mid-January (historically), this usually correlates to an east coast trough. It seems like as things are happening "a lot of people expected it"

Pretty strong Stratosphere warming already happening in the historical CDC daily dataset https://ibb.co/MRc03C6 The average time-lag of 500mb -NAO effects is +25-30 days, so that give us ~Jan 19-24 as the start of probable -NAO conditions. Here is how the NAO correlates to US temperatures [default positive]: https://ibb.co/S0rqMcL Believe it or not, the Jan 19th date matches exactly when my roll forward Jan 5-13 N. Pacific ridge in ENSO changes/reverses and becomes a +PNA/colder pattern (2 different variables in different region). So I would watch maybe Jan 21st on as a possibility to go colder, and have a wintery period in the east.

I'll include updates about the Stratosphere warming in this thread We are already hitting Stratosphere warming territory, as of Christmas: (as per the method I used to research historical -NAO correlations): https://ibb.co/Htm37sB 12-27 is already pretty strong https://ibb.co/MRc03C6 Dec 25-27 has a normal/average lag to 500mb of +25-30 days. So that makes the highest probability of -NAO conditions to start on Jan 19. Stratosphere warmings at 10mb usually last a total of 15-45 days. This one seems projected on models to go on pretty long.

We are already hitting legit Stratosphere warming territory, as of Christmas https://ibb.co/Htm37sB 12-27 is pretty strong https://ibb.co/MRc03C6

GOA stands for Gulf of Alaska. WC stands for West Coast

GOA ridge, WC trough, ridge overtop here in the east.. no way. bluewave posted something where most of our snows since 09-10 have happened with a ridge in the West as the most dominate N. Hemisphere feature (for NYC at least).

Nice to see the 540 line barely getting here in January as dark purple on that map. TT must use 91-20 averages.

That's what the ENSO analogs show https://ibb.co/xzVYnx5 But this El Nino so far has not really had much of an impact on the N. Pacific 500mb pattern so we'll see https://ibb.co/LxKM678

Look at this massive Pacific ridge on the CPC ensembles https://ibb.co/yQxk7bS I'll bump my roll forward from yesterday since it's trending more probable to happen as a dominant pattern

Coldest day of the year is Jan 27th. Precip does slightly uptick in the 2nd half of Winter vs the 1st.

We just don't do well in trend when there is a High pressure near the Aleutians. As we get closer, The relative SE ridge undercuts and the cold air gets cutoff. I have seen this so much in the last few years, that I would call it a small to no chance that this threat (Jan 7th) becomes snow. We need the Pacific to change. The only thing I can think of is that models have a equilateral wind reversal happening over Nino 3.4, and this is rushing them to develop a -PNA.

A strong High pressure in the N. Pacific ocean during the cold season is not usually an El Nino pattern. Looking at the long range models, we are going to have that feature through Jan 15th, and that is going to give us a net +epo/-pna for Dec 1-Jan 15, which compares to only 2 El Nino Winters: 65-66 and 72-73. If you look at the whole El Nino event to-date, there is no N. Pacific Ocean trough south of Alaska! https://ibb.co/LxKM678 In fact, the strongest pattern in the whole Hemisphere is a ridge over the N. Pacific warm pool (-PDO)! Considering the El Nino is around +2.1c, that's not a high correlation to its normal effects. Models are showing a strong N. Pacific High pressure (-PNA) Jan 5-13 [18z GEFS]: I composed a list of 15 analogs that had a -PNA/El Nino or [minus]+PNA/La Nina during that time, and see that the pattern usually reverses in the N. Pacific Ocean after. The roll-forward shows the Pacific pattern usually flips quickly after 1/14. By 1/19 it's +PNA. And by 1/25 it's -EPO. 500mb roll forward Animation: https://ibb.co/xzVYnx5 So ENSO-weighted analogs show that the N. Pacific pattern we are seeing on LR models is a temporary, and not permanent feature. Let's see if this reversal carries through. Here are US Temps in the roll forward: https://ibb.co/kGL4bZp