2025-2026 ENSO

[snowman19]

43 minutes ago, 40/70 Benchmark said:

The real heart to the drought is over northern New England....couple that with a modest +NAO and maybe it’s finally my turn.

You are right about the smax. High sunspots and especially high geomag argue for +NAO as does the cold North Atlantic 

[brooklynwx99]

I can assure you, when we do get a good winter from NYC south, I doubt anyone will have actually forecasted it beforehand. including myself

[40/70 Benchmark]

5 minutes ago, snowman19 said:

You are right about the smax. High sunspots and especially high geomag argue for +NAO as does the cold North Atlantic 

Yea, well don't forget the E QBO. This shouldn't be a super nova +NAO that is devoid of blocking.

[40/70 Benchmark]

IRI plume def. more aggressive with La Nina. I think they have finally caught onto to an event that will will fall just shy of official designation. I called -0.5 to -0.7 ONI peak back in July and it looks like dynamical guidance now peaks at -0.71, statistical -0.53 and mean of all guidance -0.61.

https://easternmassweather.blogspot.com/2025/07/la-neutral-enso-conditions-will.html

Will probably go onto to overcorrect a bit next month, too before tickling back later in the fall. Subsurface is quite stout, but I don't think we will have the trade clout to surface as much of that in region 3.4 as we did in 3 and 1.2.

[snowman19]

[40/70 Benchmark]

19 minutes ago, snowman19 said:

 

We need the trades colocated with the subsurface cold pool...we had that big time througout much of August, when we had the burst of intensification of La Nina due to the upwelling of the cold pool over the eastern half of ENSO. However, trades died down and shifted west in Septmeber. They look to pick up out east again next week and into October, but not as strongly as August. SOI has also been inching upwards. I think at the end of the day, the pedestrian coupling of the trades with the cold pool, owed at least in part to the diffuse PAC pressure dipole (Low west/high east) is what will have this La Nina struggling to be acknowledged by CPC in the record books. Will be very close.

The subsurface says game on...but the hemisphere isn't totally on board.

[40/70 Benchmark]

Maybe a hair stronger than last year-

[michsnowfreak]

4 hours ago, snowman19 said:

Honestly, the most concerning thing, at least as far as snowfall is the drought. These typically aren’t easy to break, especially when in place for several months. They form a feedback cycle. And parts of the northeast are historically dry

 

 

 

As far as the SE ridge, I think we do see much more SE ridging this time around due to the state of the Atlantic. BAMWX actually touched on this yesterday

 

 

 

 

 

 

I imagine color is ramping up bigtime in NNE with the drought.

Our average peak in SE MI is mid-late October, but color began in late August as the cool nights arrived and even with the pattern shift to warmer, color continues to expand. The air smells like fall with all the drying leaves, even in the warm sun, and I suspect the dry conditions have to be playing a part. 

Kind of hard to tell in this picture from earlier, but the gold of the grass is only a few shades lighter than the gold on the trees.

 

[snowman19]

I imagine color is ramping up bigtime in NNE with the drought.
Our average peak in SE MI is mid-late October, but color began in late August as the cool nights arrived and even with the pattern shift to warmer, color continues to expand. The air smells like fall with all the drying leaves, even in the warm sun, and I suspect the dry conditions have to be playing a part. 
Kind of hard to tell in this picture from earlier, but the gold of the grass is only a few shades lighter than the gold on the trees.
 

It’s been insanely dry since the end of July

[Stormchaserchuck1]

The newly released CPC Winter outlook is colder than 90-95% of what they've put out in the long range for the last 10 years, for the CONUS. 

The NW, US is an interesting forecast, because the Euro, CANSIPs, and other seasonal models are above average there. 

[TheClimateChanger]

1 hour ago, Stormchaserchuck1 said:

The newly released CPC Winter outlook is colder than 90-95% of what they've put out in the long range for the last 10 years, for the CONUS. 

The NW, US is an interesting forecast, because the Euro, CANSIPs, and other seasonal models are above average there. 

They are forecasting A LOT of drought though:

[PhiEaglesfan712]

[snowman19]

[GaWx]

 Although the chances are now pretty low, we still don’t know for sure that ACE won’t get to near the 30 yr 122 avg especially based on 2024, 2020, 2016, and 2005, but also on 1894, 1893, and 1878. However, all of these very active Oct+ years were more active through Sept though 2016 and 1894 not by that much.

[anthonymm]

19 hours ago, Stormchaserchuck1 said:

The newly released CPC Winter outlook is colder than 90-95% of what they've put out in the long range for the last 10 years, for the CONUS. 

The NW, US is an interesting forecast, because the Euro, CANSIPs, and other seasonal models are above average there. 

they always predict a very cold PNW if it's a nina. Also it is impressive how little orange they used!

[snowman19]

Also, a very strong -IOD signature here

[Daniel Boone]

20 hours ago, Stormchaserchuck1 said:

The newly released CPC Winter outlook is colder than 90-95% of what they've put out in the long range for the last 10 years, for the CONUS. 

The NW, US is an interesting forecast, because the Euro, CANSIPs, and other seasonal models are above average there. 

Enso is always their main source for their Seasonals, as we all know. 

[PhiEaglesfan712]

1 hour ago, GaWx said:

 Although the chances are now pretty low, we still don’t know for sure that ACE won’t get to near the 30 yr 122 avg especially based on 2024, 2020, 2016, and 2005, but also on 1894, 1893, and 1878. However, all of these very active Oct+ years were more active through Sept though 2016 and 1894 not by that much.

Three of those years rank among the 11 hyperactive (180+ ACE) seasons, with 2 of the Top 3 overall:

1            2005      247.65

3            1893      231.0738

11          2020      180.3725

[raindancewx]

Here is how the global blend I mentioned a while ago looks for September - 2013, 2018, 2022, 2024 minus 2007. Not half bad. 

Given that ACE is heavily favored to finish under 100 now, I'd go colder than the blend with -2007, especially Plains/Southwest.

[snowman19]

@Gawx

[snowman19]

@Stormchaserchuck1 IMO we are on the verge of finally going into a -AMO cycle

[bluewave]

2 hours ago, snowman19 said:

@Stormchaserchuck1 IMO we are on the verge of finally going into a -AMO cycle

Still looks pretty warm to me since the Atlantic is currently the 5th warmest on record for the date. We also have to remember that this is the warmest 1991-2020 climo. So the actual historical ranking is pretty high.

The cold pool west of Ireland is from the locally stronger winds there with the deep low pressure. 

 

[GaWx]

3 hours ago, snowman19 said:

@Gawx
 

 

 

 

 

 What do you and others think about the Nov 1950-March 1951 weak La Ninaish ENSO before warming up late as an analogue for 2025-6? A well-known met. got on that train yesterday due to an anticipated active late tropical season having the potential to be similar to Oct of 1950 based on precip anomaly progs by the longer term Euro. This met. talked about the severe effects on the NE US caused by the 11/25/1950 superstorm.

[snowman19]

12 minutes ago, GaWx said:

 What do you and others think about the Nov 1950-March 1951 weak La Ninaish ENSO before warning up late as an analogue for 2025-6? A well-known met. got on that train yesterday due to an anticipated active late tropical season having the potential to be similar to Oct of 1950 based on precip anomaly progs by the longer term Euro. This met. talked about the severe effects on the NE US caused by the 11/25/1950 superstorm.

I don’t think we are going to see a big October burst in Atlantic tropical activity. This is how many months in a row now that people have been saying a big burst is coming? The finish line just keeps getting moved further and further forward in time. Now it’s October. This is becoming The Boy Who Cried Wolf. Eventually you have to acquiescence and admit defeat

[PhiEaglesfan712]

33 minutes ago, GaWx said:

 What do you and others think about the Nov 1950-March 1951 weak La Ninaish ENSO before warming up late as an analogue for 2025-6? A well-known met. got on that train yesterday due to an anticipated active late tropical season having the potential to be similar to Oct of 1950 based on precip anomaly progs by the longer term Euro. This met. talked about the severe effects on the NE US caused by the 11/25/1950 superstorm.

I like 1949-50 as an analog better than 1950-51. (By the way, those years still hold the record for the least snowy 2-year period at PHL.) 50-51 was a very active Atlantic hurricane season. By my calculation, it is the 5th highest ACE season at 227.1413 (Wunderground has it as the 2nd highest at 243). We don't have anywhere near that this year.

November 1950 was month of weird extremes. In some places in the east, you had high temperatures in the 80s (at the beginning of the month), and by the 25th, you had low temperatures near 0.

[DarkSharkWX]

decent amount of bob warming recently

[snowman19]

decent amount of bob warming recently

I think the question becomes when does the -IOD bottom out? Did it bottom out already or do we see another burst of strengthening in October. Either way the BOM and all models are projecting the -IOD event to continue the next few months. From the BOM: “The Indian Ocean Dipole (IOD) index has now met the negative IOD threshold (less than or equal to −0.4 °C) for 8 consecutive weeks, sufficient to be classified as a negative IOD event. The latest IOD index value for the week ending 14 September 2025 is −1.17 °C.
The Bureau's model predicts the negative IOD event to continue throughout spring, with a return to neutral in early summer. This is consistent with most international models assessed and the typical IOD life cycle.”

https://www.bom.gov.au/climate/enso/?ninoIndex=nino3.4&index=rnino34&period=weekly#tabs=Indian-Ocean

[GaWx]

20 hours ago, raindancewx said:

Here is how the global blend I mentioned a while ago looks for September - 2013, 2018, 2022, 2024 minus 2007. Not half bad. 

Given that ACE is heavily favored to finish under 100 now, I'd go colder than the blend with -2007, especially Plains/Southwest.

 I continue to fear what late seasons are capable of producing based especially on the recent past. Having 3 of the 7 most active Oct-Dec periods ACEwise (70+) during just the last 9 seasons is not comforting at all. Moreover, 3 of the last 6 (50%) La Niña seasons (2024 per RONI counts as La Niña) were in these top 7! 

 The one somewhat comforting thing, however, is the relative slowness of 2025 so far and how that affects the chances for a highly active Oct-Dec. There appears to be some correlation between how active a season is prior to Oct and how active is a season Oct-Dec, which means that having a relatively slow season through Sep does appear to reduce the chance for a very active Oct-Dec (50+ ACE) somewhat vs that chance when pre-Oct isn’t slow:

Seasons with 50+ ACE during Oct-Dec:

Year/pre-Oct ACE/Oct+ ACE
2024: 78/84
2020: 106/75
2016: 59/80
2005: 171/75
1969: 93/57
1963: 49/63
1961: 134/55
1950: 157/54
1932: 87/82
1894: 59/76
1893: 159/73
1887: 123/59
1878: 84/97

 Per this list based on each era’s normal ACE, the pre-Oct ACE for these 13 very active Oct-Dec was as follows:

- 6 MA normal (2005, 1961, 1950, 1893, 1887, 1878)
- 3 AN (2020, 1969, 1932)
- 1 NN (1894)
- 3 BN (2024, 2016, 1963)

 So, 50+ Oct-Dec years have been heavily biased toward pre-Octs that were active.

Where is 2025 headed for pre-Oct? Through Gabrielle, the prog is for ~~55. Then there’s the current MDR orange. The consensus has this as TS Humberto by 9/26-7 and a H soon after. That would have a realistic potential of 10-15 ACE 9/26-30. So, that would get total 2025 pre-Oct ACE to as much as ~65-70. That compares to 94 for the 1991-2020 pre-Oct avg, which means 2025 pre-Oct will end up solidly BN just about regardless of what Gabrielle and Humberto do.

What does this tell me? With 2025 almost definitely headed for BN pre-Oct, the chance for a 50+ Oct-Dec is <50%. However, 2024, 2016, and 1963 as well as 3 of the most active 7 Oct-Dec on record having occurred just within the last 6 La Niña seasons also say don’t bet the farm on <50 for Oct-Dec at least as of yet.