Mid-Long Range Discussion 2026

[suzook]

2 hours ago, GaWx said:

The 12Z EPS for SAV has gotten my attention for the small chance of Sun AM light snow/flurries, which in this area would be a big deal due to the relative rarity being that most winters get nothing, not even a T. We got nothing Feb 2018 through Dec 2024.
 

 My expectations, especially for measurable, are low due to climo, it being pretty dry overall with member qpf progs being light, and marginal temps.

So, fwiw, here are some 12Z EPS images: ~25% of members have snow, which is notably high:

 

Mean: 0.2”, notable for here:

As much as I would like to believe this, it's been dry as f here. Every precip chance just fizzles out. I'm just thinking it will be dry

[Coach McGuirk]

Late January looks interesting. 

[Jimbo!]

I see potential near 24-26 and I’d bet it does a rare s trend. My surgery on the 14th got rescheduled til the 26th cause surgeon was sick.


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[BornAgain13]

1 hour ago, BooneWX said:

Funny you say that: the NBM’s footprint is further west tonight than some of the snowier OPs we saw at 18z. It would favor Delmarva southwest through the Virginia/NC piedmonts into western NC.

U have a map of the NBM?

[GaWx]

From Don Sutherland:

Yes, the PNA is far more important to Atlanta's January snowstorms than the NAO. Since 1950, the PNA was positive for 84.2% of Atlanta's 1" or greater snowstorms. The NAO was negative for 63.2% of such storms.

 I’ll add that that these Jan snowstorms were during La Niña:

Dates……PNA…….NAO

1/15-17/1965…+1.191…+0.438

1/6-8/1996…+0.289…-0.640

1/19/2008…+0.430…+0.287

1/9-10/2011…-0.223…-0.524

1/16-17/2018…+0.101…+1.430

1/10/2025…+1.105…-1.208

 

 So, just for the six 1”+ Jan storms during La Nina:

-5 of the 6 PNAs were >0 and the lowest was only down to -0.223. Avg PNA was +0.5

-In contrast, 3 of the 6 NAOs were positive with one of them strongly positive. The avg NAO was near 0/neutral.

—————

 The 1/18/26 potential SE snowstorm looks like it will be during a moderate MJO phase 6, a strong +PNA, a neutral to moderately -AO, slightly + to neutral NAO, -WPO, and a very strong -EPO, which may be sub -3 then.

 So, the highlight is strong +PNA/-EPO during a phase 6.

[BooneWX]

U have a map of the NBM?

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[Daniel Boone]

55 minutes ago, GaWx said:

From Don Sutherland:

Yes, the PNA is far more important to Atlanta's January snowstorms than the NAO. Since 1950, the PNA was positive for 84.2% of Atlanta's 1" or greater snowstorms. The NAO was negative for 63.2% of such storms.

 I’ll add that that these Jan snowstorms were during La Niña:

Dates……PNA…….NAO

1/15-17/1965…+1.191…+0.438

1/6-8/1996…+0.289…-0.640

1/19/2008…+0.430…+0.287

1/9-10/2011…-0.223…-0.524

1/16-17/2018…+0.101…+1.430

1/10/2025…+1.105…-1.208

 

 So, just for the six 1”+ Jan storms during La Nina:

-5 of the 6 PNAs were >0 and the lowest was only down to -0.223. Avg PNA was +0.5

-In contrast, 3 of the 6 NAOs were positive with one of them strongly positive. The avg NAO was near 0/neutral.

—————

 The 1/18/26 potential SE snowstorm looks like it will be during a moderate MJO phase 6, a strong +PNA, a neutral to moderately -AO, slightly + to neutral NAO, -WPO, and a very strong -EPO, which may be sub -3 then.

 So, the highlight is strong +PNA/-EPO during a phase 6.

Just looking at MJO Charts one would expect a mild Pattern in the East. Goes to show other Drivers sometimes dictate or throw the MJO effects off kilter. Even the location of La nina apparently according to some research. 

[Daniel Boone]

12 minutes ago, BooneWX said:

.

It's a blend of the Model's as most know as it's pretty obvious. I don't know how many are used or which one's to come up with the Average of them all. It's been awhile since I was told by the NWS . They just explained it and said it's the one they use.

I don't think any Model's are given more weight than the others. If the better Model is showing 10" for a given area while 2 of the worst are showing zilch, the printout is going to be very low and may be way off.

   So, it's overall a good Idea Model. You get the average of the Consensus so to speak but, it can sometimes be way off because of what I mentioned above. 

[GaWx]

19 minutes ago, Daniel Boone said:

Just looking at MJO Charts one would expect a mild Pattern in the East. Goes to show other Drivers sometimes dictate or throw the MJO effects off kilter. Even the location of La nina apparently according to some research. 

 Actually, I did a study recently that surprisingly showed that Jan phase 6 in the SE (using GSP as a representative) has had a mix with a bit more cold vs warm phase 6 Jan periods. Examples of cold during La Niña in Jan:

1975 (8 BN), 1976 (9 BN during a long period of 13 days), 2000 (4 BN), 2011 (7 BN during a long period of 12 days), 2022 (9 BN), and 2025 (5 BN). 
 
 There were some mild Jan phase 6 periods during La Niña also like 1989 (+8) and 2008 (+8) although those two were only 3 days long each.

Keep in mind though that the current phase 6 started off mild. So, it remains to be seen how cold it will end up overall as it’s progged to last through ~Jan 21st.

 

[Daniel Boone]

1 minute ago, GaWx said:

 Actually, I did a study recently that surprisingly showed that Jan phase 6 in the SE (using GSP as a representative) has had a mix with a bit more cold vs warm phase 6 Jan periods. Examples of cold during La Niña in Jan:

1975 (8 BN), 1976 (9 BN during a long period of 13 days), 2000 (4 BN), 2011 (7 BN during a long period of 12 days), 2022 (9 BN), and 2025 (5 BN). 
 
 There were some mild Jan phase 6 periods during La Niña also like 1989 (+8) and 2008 (+8) although those two were only 3 days long each.

Yes. That's what I was referring to irt research. I'd saw a thing or two on where you had did that. Was that dependant on La nina location Larry ?