2025-2026 ENSO

[donsutherland1]

8 minutes ago, stadiumwave said:

Winter cancel?

0z EPS DEC 4

The 0z EPS rolls the cold forward pretty much as one would expect with a WPO-/EPO-/AO-/PNA- pattern evolution. One sees how the Great Lakes/Upper Midwest is the focus of the cold while warmth proves very persistent in the Southeast.

 

288 hours:

312 Hours:

336 Hours:

360 Hours:

The usual caveats concerning skill apply that these timeframes. Moreover, how the stratospheric warming propagates will influence the pattern evolution for the second half of the month. 

[MJO812]

47 minutes ago, Stormchaserchuck1 said:

That's at odds with the end of the EPS. You're posting a 1.5 day old model. 

Yesterday vs today

This is also phase 8. 

[Stormchaserchuck1]

^That's a massive +NAO, MJO. With heights over Alaska neutralizing, we are going to go really warm there. These are large scale features that have a big impact on the east coast. Look at how the ridging in Alaska is just about gone in that 360hr map. If we don't hold that, the cold pattern is going to fall. 

[mitchnick]

18 minutes ago, mitchnick said:

The question is what period you're discussing. There are conflicting signs the way I see it. Even conflicts with the models' own MJO forecasts and 5H forecasts. In the end, all that be done is to look at modeling and hug whichever one suites one's opinion/gut/biases since everything remains on the table once out 7+ days. But we can't deny the medium and long range forecasts this year of warm, like last year, have not been great. So that along with a weak Niña on its way out the door by year end with noticeable western Pacific cooling, I think the urge to assume warmer LR forecasts are going to verify is risky for now. If they do verify, that will change things in my weenie mind.

 

As evidence of my statement that longer range forecasts haven't done well this year, top pick is last night's EPS forecast for Black Friday 12z and bottom forecast us from 11/15 12z.

[Stormchaserchuck1]

3 minutes ago, mitchnick said:

As evidence of my statement that longer range forecasts haven't done well this year, top pick is last night's EPS forecast for Black Friday 12z and bottom forecast us from 11/15 12z.

Come on man.. there is like 1 instance of a ridge leading to a trough in the east coast over the last year, and it's already been posted like 3 times lol. The large scale features held: -epo, +pna. I don't know why it had a big ridge when the Pacific looked like that anyway, but you know long range models hit at about 0.80 correlation accuracy. Especially when 1,000 mile wide features have a strong signal. It's predictable. 2-4 week models are much less predictable, there is a pretty big fall off after 384hr in predictability. 

[Stormchaserchuck1]

I'm personally not a big fan on long range MJO forecastability. I've seen a lot of times actually over the last 10 years where patterns drastically change when the MJO is projected to go into favorable phases for X. 

[mitchnick]

1 minute ago, Stormchaserchuck1 said:

Come on man.. there is like 1 instance of a ridge leading to a trough in the east coast over the last year, and it's already been posted like 3 times lol. The large scale features held: -epo, +pna. I don't know why it had a big ridge when the Pacific looked like that anyway, but you know long range models hit at about 0.80 correlation accuracy. Especially when 1,000 mile wide features have a strong signal. It's predictable. 2-4 week models are much less predictable, there is a pretty big fall off after 384hr in predictability. 

Come on what? It's a perfect example that the models are doing poorly with warm forecasts and second, we're all wasting our time with these digital slot machines we call models! Lol

[Stormchaserchuck1]

Just now, mitchnick said:

Come on what? It's a perfect example that the models are doing poorly with warm forecasts and second, we're all wasting our time with these digital slot machines we call models! Lol

In the bigger picture, it's not really a big deal. It happens rarely. I think the other notable one was in August when a lot of models were warm in the long range and it ended up being cool. 

[donsutherland1]

Here's my thinking based on the latest guidance and some of the longer-range guidance. I focus on what I believe are the three biggest potential scenarios for much of December.

[stadiumwave]

1 hour ago, donsutherland1 said:

The 0z EPS rolls the cold forward pretty much as one would expect with a WPO-/EPO-/AO-/PNA- pattern evolution. One sees how the Great Lakes/Upper Midwest is the focus of the cold while warmth proves very persistent in the Southeast.

 

288 hours:

312 Hours:

336 Hours:

360 Hours:

The usual caveats concerning skill apply that these timeframes. Moreover, how the stratospheric warming propagates will influence the pattern evolution for the second half of the month. 

 

Dump west...bleed east

[anthonymm]

14 minutes ago, donsutherland1 said:

Here's my thinking based on the latest guidance and some of the longer-range guidance. I focus on what I believe are the three biggest potential scenarios for much of December.

Not to be a weenie but what makes you think it’s “very unlikely” the pna flips positive for a period in december?

[stadiumwave]

15 minutes ago, donsutherland1 said:

Here's my thinking based on the latest guidance and some of the longer-range guidance. I focus on what I believe are the three biggest potential scenarios for much of December.

Great post! 

CFS: AO

[donsutherland1]

49 minutes ago, Stormchaserchuck1 said:

I'm personally not a big fan on long range MJO forecastability. I've seen a lot of times actually over the last 10 years where patterns drastically change when the MJO is projected to go into favorable phases for X. 

And going beyond the lack of skill in MJO forecasts beyond 10 days, other factors can overwhelm it. Sometimes even high amplitude passages through Phase 8 during  passage through Phases 7-2 don't generate a wintry response in North America. December 1-12, 1990 is one example.

March 1-25, 2023 is another example, even as it was an off-the-scales passage through Phase 8.

 

[donsutherland1]

17 minutes ago, anthonymm said:

Not to be a weenie but what makes you think it’s “very unlikely” the pna flips positive for a period in december?

The teleconnection idea (predominant state during the periods) is based on the GEFS and EPS, including the weekly EPS ideas. That's why I noted that the probability for Scenario 3 has increased somewhat, as some of the guidance now moves toward a more robust AO+. The consensus remains a persistent PNA- (closer to neutral but not positive). Here's the latest GEFS forecast going into December (preponderance of ensemble members show a PNA<0):

[stadiumwave]

1 hour ago, mitchnick said:

As evidence of my statement that longer range forecasts haven't done well this year, top pick is last night's EPS forecast for Black Friday 12z and bottom forecast us from 11/15 12z.

 

We too quickly buy as gospel LR guidance, which in my experience seems to be at its worst in the winter months. Best to take warmth or cold with a grain of salt. 

[stadiumwave]

5 minutes ago, donsutherland1 said:

And going beyond the lack of skill in MJO forecasts beyond 10 days, other factors can overwhelm it. Sometimes even high amplitude passages through Phase 8 during  passage through Phases 7-2 don't generate a wintry response in North America. December 1-12, 1990 is one example.

March 1-25, 2023 is another example, even as it was an off-the-scales passage through Phase 8.

 

 

To your point...DEC, 2010. First half of DEC was in low-amp MJO phases 3,4,5,6 (blue line is DEC):

Here are the 2m Temps for DEC 1-20:

 

Certainly other factors can override MJO.

[FPizz]

After Dec 2 the pattern has a 2013 look to it if it comes to fruition.  Credit to a met on another page.

[GaWx]

45 minutes ago, donsutherland1 said:

And going beyond the lack of skill in MJO forecasts beyond 10 days, other factors can overwhelm it. Sometimes even high amplitude passages through Phase 8 during  passage through Phases 7-2 don't generate a wintry response in North America. December 1-12, 1990 is one example.

March 1-25, 2023 is another example, even as it was an off-the-scales passage through Phase 8.

 

12/9-14/91 also was a mild strong phase 8 in the E US though it cooled afterward:

[stadiumwave]

1 minute ago, GaWx said:

12/9-14/91 also was a mild phase 8 in the E US though it cooled afterward:

 

The can be a lag. I know Roundy has said such a common mistake is to think MJO phase correlation automatically or immediately shows up. Both are a mistake to think. 

[GaWx]

6 minutes ago, stadiumwave said:

 

The can be a lag. I know Roundy has said such a common mistake is to think MJO phase correlation automatically or immediately shows up. Both are a mistake to think. 

 Whereas there can be a lag, the diagrams by phase are based on concurrent temps. So, phase 8 being the coldest in Dec is based on temps during phase 8 being the coldest of any phase rather than with a lag.

[MJO812]