2025-2026 ENSO

[WVclimo]

1 hour ago, MJO812 said:

Euro is now colder in the long range . All the models have trended colder. 

Euro is frigid

[40/70 Benchmark]

55 minutes ago, WVclimo said:

I'm waiting for Bluewave to embed a tweet about how fast of a flight it was from Tokyo to San Francisco, and then a 1994-2015 minus 2016-2025 250mb zonal wind graphic

[brooklynwx99]

Pacific jet is trending more equatorward towards mid-month, leading to a better wave break and more poleward ridging near AK… this makes sense given the MJO 

[SnowGoose69]

2 minutes ago, brooklynwx99 said:

Pacific jet is trending more equatorward towards mid-month, leading to a better wave break and more poleward ridging near AK… this makes sense given the MJO 

GEFS/GEPS in a snap shot mindset do not look great D14-16, but they're in the process it seems of evolving to something different.  A ton likely depends on where the MJO goes

[Daniel Boone]

9 minutes ago, 40/70 Benchmark said:

I'm waiting for Bluewave to embed a tweet about how fast of a flight it was from Tokyo to San Francisco, and then a 1994-2015 minus 2016-2025 250mb zonal wind graphic

You know he's working on something, lol.

[40/70 Benchmark]

11 minutes ago, Daniel Boone said:

You know he's working on something, lol.

He has a varied approach...may also be a Pacific SST chart along with sentence or six about how the models embellish phase 8 of the MJO in this "new, warmer climate".

[40/70 Benchmark]

I swear he has an alarm on his Iphone that is triggered whenever MJO812 smiles.

[MJO812]

[40/70 Benchmark]

1 minute ago, MJO812 said:

The larger test is mid month and onward.

[bncho]

lets listen to @MJO812 whenever the MJO might enter 8-1-2. it's literally in his name!

[brooklynwx99]

16 minutes ago, SnowGoose69 said:

GEFS/GEPS in a snap shot mindset do not look great D14-16, but they're in the process it seems of evolving to something different.  A ton likely depends on where the MJO goes

I agree that they don’t look as good… given the MJO progression, I feel like the EPS makes more sense. we’ll see

[40/70 Benchmark]

2 minutes ago, brooklynwx99 said:

I agree that they don’t look as good… given the MJO progression, I feel like the EPS makes more sense. we’ll see

Given the progression of the reflection event coupled with a weakening MJO wave, the GEFS make more sense to me mid month. Re-consolidating PV and developing PT regime.

[TheClimateChanger]

How's the weather looking in Ann Arbor on Saturday? Hearing rumors of snow for The Game?

[leo2000]

26 minutes ago, 40/70 Benchmark said:

Given the progression of the reflection event coupled with a weakening MJO wave, the GEFS make more sense to me mid month. Re-consolidating PV and developing PT regime.

The data seems to show though that this SSW event is a combined reflective-absorptive sudden stratospheric warming event. The reflection phase allows for the Alaskan Ridge and a positive AO and positive NAO in the near term. 

• Absorbing Phase: Subsequently, the stratosphere switches to an absorbing state, where it absorbs the upward wave energy, leading to a breakdown or weakening of the polar vortex. This absorption phase causes downward propagation of anomalous winds and is typically associated with a negative phase of the AO/NAM, leading to an increased likelihood of cold air outbreaks in mid-latitudes, particularly across North America and Eurasia. 

 

 

Tropospheric Impacts

The distinct phases of a combined event lead to a sequence of different weather impacts on the Earth's surface: 

• Near-term (Reflective Phase): Stronger westerlies and an active storm track across northern Europe may be observed, with temporary ridging in the North Pacific.
• Medium-term (Absorptive Phase): Increased pattern uncertainty emerges as the vortex breaks down, typically leading to the negative AO pattern and potential severe winter cold in mid-latitude regions. 

From Met Jens Bonewitz 

Stratospheric Update: hashtag#Potential Combined Reflective-Absorptive hashtag#SSW Developing!
Following yesterday's discussion (link: https://lnkd.in/egEFCFuq), models continue to indicate persistent hashtag#wave-1 forcing on the stratospheric polar vortex (SPV) extending into December—this time driven primarily by an intensifying hashtag#Aleutian Low.


We may be witnessing a combined or consecutive reflective-absorptive hashtag#SSW event. As discussed in the recent hashtag#Hannachi et al. (2025) paper, these complex events occur when upward propagating planetary waves first reflect off the disturbed vortex (creating negative heat fluxes that temporarily strengthen the SPV and accelerate the polar jet), before subsequently being absorbed, leading to vortex breakdown and downward wave activity flux propagation to the troposphere.

Expected hashtag#Tropospheric Response:
Near-term (into early hashtag#December):
hashtag#Pacific: Temporary Alaskan Ridge (AkR) development;
N Atlantic: Positive AO/NAO as reflected waves accelerate the jet stream—stronger westerlies and active storm track across northern EuropMedium-term (mid-late December):
Increasing pattern uncertainty as absorption phase dominates.
Downward coupling from the disturbed SPV likely triggers AO/NAO trend reversal. Enhanced (negative) blocking potential across Atlantic-European sector.

Key hashtag#Uncertainty:
The timing and magnitude of stratosphere-troposphere coupling in consecutive wave forcing events remains highly non-linear. While the ~60-day lag framework provides guidance, the volatile nature of this setup challenges deterministic forecasts beyond 2-3 weeks.

hashtag#Graphics (attached):
Time-height evolution of max.wave-1 height amplitude showing sustained and intense forcing in the upper and into the middle stratosphere (1-10 hPa) from late November through early December; source, incl.latest hashtag#forecast: https://lnkd.in/esD7gEtP. The persistent high-amplitude wave activity (>1500-1900 gpdm in the upper stratosphere) represents the continuous pressure on the polar vortex—key driver for the potential reflective-absorptive hashtag#SSW sequence.

Additional Context: 500 hPa hashtag#GFS forecast (30 Nov) showing the main tropospheric driver: intense hashtag#Aleutian Low. Note the deep low pressure system over the North Pacific providing upward wave forcing into the stratosphere.

Additional diagnostics:
https://lnkd.in/eM2nHteb
https://lnkd.in/eXr7cGtG

[MJO812]

27 minutes ago, 40/70 Benchmark said:

Given the progression of the reflection event coupled with a weakening MJO wave, the GEFS make more sense to me mid month. Re-consolidating PV and developing PT regime.

But the MJO is forecast to spend 7 to 10 days in phase 8. Im not sure if its going to be warm mid month. I can see a slight warmup but nothing lasting 

[Daniel Boone]

46 minutes ago, 40/70 Benchmark said:

Given the progression of the reflection event coupled with a weakening MJO wave, the GEFS make more sense to me mid month. Re-consolidating PV and developing PT regime.

Yeah, the reflection thing is a concerning Factor for sure. As mentioned earlier, it will make for an interesting forecast period with the MJO in cold Phases.

[LakePaste25]

The effects of the SSW look to completely decouple from the surface (for now).