2026-2027 Record-breaking El Nino

[40/70 Benchmark]

28 minutes ago, 40/70 Benchmark said:

It comes down to the position of the ridge, which should be over se Canada, so I doubt it will be too warm in the NE. Maaaaaaybe the se.......

23-24 it was over se Canada, so it was too cool anywhere near that ridge.

Last year it was too cool in the SW, under the ridge.

This should be pretty accurate, so forecast maybe about right for the northeast and could be a hair warm south of about DC....but another trend we have seen is for the ridges to verify south of forecast, which places "too cool" on the able for the NE forecast, if that were to be the case.

[mitchnick]

8 minutes ago, 40/70 Benchmark said:

This should be pretty accurate, so forecast maybe about right for the northeast and could be a hair warm south of about DC....but another trend we have seen is for the ridges to verify south of forecast, which places "too cool" on the able for the NE forecast, if that were to be the case.

Definitely expect some adjustments over the next 2 months...hopefully not in the wrong direction. After that, it's December with the daily weeklies update! What a drug this hobby can be! Lol

[LakePaste25]

Officially crossed +3C on ONI and +2.5C on RONI!

 

[Stormchaserchuck1]

8 hours ago, bluewave said:

Even single model forecasts have been missing the magnitudes of the ridges and the warmth underneath. But this is to be expected due to the much lower resolution and nature of long range forecasts beyond 15 days.

In our rapidly warming climate there have been many more opportunities for the models to be biased too cold than too warm.

So it’s beyond technology of present day weather forecast models to have been able to see the historic 600 dm ridge this week from beyond 5-10 days out.

 

 

Are we really getting such a large 500mb ridge? Surface temps aren't as impressive as H5. That's actually not too far away from the all time US record. I wonder if we are shattering mid-Sept US record?

[GaWx]

38 minutes ago, Stormchaserchuck1 said:

Are we really getting such a large 500mb ridge? Surface temps aren't as impressive as H5. That's actually not too far away from the all time US record. I wonder if we are shattering mid-Sept US record?

Chuck,

 I’m thinking that the reason the 2m anomalies aren’t as impressive as the H5 anomalies is probably that there’s a lot of Atlantic origin moist and cooler air in the 2m mix as opposed to drier and hotter land based air.

 Opinions?

[GaWx]

10 hours ago, GaWx said:

Latest (0Z of Sep 15th) CFSv2 AAM forecast, which is already at a very high >+3, is like yesterday progging an off the charts extreme/historic? +4+ starting by Sep 19th (earliest in the forecast I’ve ever seen) and lasting at least through Sep 24th:

9/15 12Z CFSv2 consistent with 0Z run having AAM on Sep 19th go to a historical extreme level (+4+):

[raindancewx]

Still following the progression of the four most recent El Ninos, but at much more extreme severity.

The +15F stuff centered over Kansas should wash out a bit by the end of the month, same for the -5 to -10 centered on Oregon.

We're seeing widespread heavy rains this month in New Mexico after very little rain in June-Aug. Will be curious to see how the month finishes locally. But 2015/2018/2023 had fairly wet Septembers as well locally.

 

[Stormchaserchuck1]

Should be interesting to see if we follow the last 3 El Nino's post-2016 PDO-change in October with a SE ridge and an area of real cold. 

1948-2020 Oct Nino:

[bluewave]

12 hours ago, Stormchaserchuck1 said:

Are we really getting such a large 500mb ridge? Surface temps aren't as impressive as H5. That's actually not too far away from the all time US record. I wonder if we are shattering mid-Sept US record?

https://forecast.weather.gov/product.php?site=NWS&issuedby=OHX&product=AFD&format=CI&version=1&glossary=1

Dangerous heat is the main concern this week, especially during
the afternoon hours. A powerful 6000+ meter 500 mb ridge over the
region will keep conditions hot and humid with no meaningful rain
potential.

BNA reached a record-setting 100 degrees Tuesday and there is no
reason to doubt it will happen again Wednesday as the ridge
intensifies directly overhead. Record high temperatures are in
jeopardy each day this week.

[GaWx]

 The E US heat of Sept 2026 is somewhat similar to the intense E US heat of another El Niño Sept, that of record breaking 1925.

[michsnowfreak]

1 hour ago, GaWx said:

 The E US heat of Sept 2026 is somewhat similar to the intense E US heat of another El Niño Sept, that of record breaking 1925.

Any idea the strength of the 1925-26 Nino?

[GaWx]

2 hours ago, michsnowfreak said:

Any idea the strength of the 1925-26 Nino?

Per Eric Webb’s table, 1925-6 trimonthlies peaked at +1.3.

[frontranger8]

20 hours ago, Stormchaserchuck1 said:

Should be interesting to see if we follow the last 3 El Nino's post-2016 PDO-change in October with a SE ridge and an area of real cold. 

1948-2020 Oct Nino:

Yep, severe cold snaps and huge snowstorms is a common hallmark of Nino falls for the middle of the country, here included.

[GaWx]

5th CFSv2 AAM run in a row with an extreme/historic level of 4+ being progged starting Sep 19th! It looks like it’s going to actually happen, folks! My inner weenie is genuinely excited:

 

 

 

 

[Stormchaserchuck1]

Must be one heck of an El Nino pattern in the Southern Hemisphere. 

[Stormchaserchuck1]

498dm in the Arctic circle for the next 4 days. Continuing the warm season theme from 2024 and 2025. 

[MJO812]

https://www.severe-weather.eu/long-range-2/new-polar-vortex-emerging-winter-2026-2027-disruption-forecast-stratospheric-warming-trend-united-states-canada-europe-fa/

[40/70 Benchmark]

5 hours ago, GaWx said:

5th CFSv2 AAM run in a row with an extreme/historic level of 4+ being progged starting Sep 19th! It looks like it’s going to actually happen, folks! My inner weenie is genuinely excited:

 

 

 

 

Uh oh....Larry is aroused

[bluewave]

September 500mb  ridge axis continues to be much further south and stronger than past developing super El Niño events. This has lead to the record warmth across the CONUS this month. At the least the trough near the West Coast matches with the other years. But it’s a weaker area of low pressure than 1997.
 

 

 

[40/70 Benchmark]

1 hour ago, MJO812 said:

https://www.severe-weather.eu/long-range-2/new-polar-vortex-emerging-winter-2026-2027-disruption-forecast-stratospheric-warming-trend-united-states-canada-europe-fa/

I think he needs to do a better job of emphasizing that a full reversal is less likely than a stretch and/or reflection event, as he completely neglects the solar and QBO aspects, which are pretty hostile. I could see something like the scenario he laid out from January 2016 (I used this season as a strong polar analog), but I don't think a full reversal is as likely as he seems to intimate.

[40/70 Benchmark]

12 minutes ago, bluewave said:

September 500mb  ridge axis continues to be much further south and stronger than past developing super El Niño events. This has lead to the record warmth across the CONUS this month. At the least the trough near the West Coast matches with the other years. But it’s a weaker area of low pressure than 1997.
 

 

 

This makes sense, though, if you consider that the N hemisphere was not at all redolent of El Nino throughout the summer, likely due in large part to the antecedent state of the extra tropical Pacific. If that were to begin to change, this is what it would look like. I think October will be the month that will really be telling, which I know you have posted data to the same effect.

[adam7288]

On 9/15/2026 at 8:21 PM, GaWx said:

9/15 12Z CFSv2 consistent with 0Z run having AAM on Sep 19th go to a historical extreme level (+4+):

Any chance you can explain what this means? Tried googling AAM nothing useful came up.

[mitchnick]

27 minutes ago, adam7288 said:

Any chance you can explain what this means? Tried googling AAM nothing useful came up.

Try "Global Relative AAM"

[soadforecasterx]

Climate Drivers: Anomalously high relative AAM values frequently occur during El Niño events and specific active phases of the Madden-Julian Oscillation (MJO) due to broad westerly wind anomalies in the tropics and subtropics.

[soadforecasterx]

Seems like we are still seeing some good heating going on to push this el nino stronger. 

[40/70 Benchmark]

32 minutes ago, adam7288 said:

Any chance you can explain what this means? Tried googling AAM nothing useful came up.

Basically, high AAM means that the hemisphere is more representative of warm ENSO, low AAM cool ENSO.