2025-2026 ENSO

[GaWx]

On Nov 29th, the WCS daily PDO rose from ~-0.81 to -0.52, the fastest daily rise since Sept. 2nd:

[MJO812]

https://x.com/commoditywx/status/1995575448089309449?s=19

Another warming event on the way

[MJO812]

[Krs4Lfe]

42 minutes ago, MJO812 said:

Maue has become quite the hype over the past few years as far as weather Twitter goes. Long range (over next few weeks) looks active which is good. It’s good that we have the cold air (though tjat will warm up a bit in mid month, and I’m sure we will torch around Christmas) but timing the cold air during the storminess is a hard sell over in these parts 

[bluewave]

19 hours ago, leo2000 said:

So we should expect the models to be getting colder?. For some reason the Ak vortex is still there plus the EPS this morning did not look that cold. 

The split forcing that I mentioned is preventing s clean MJO 8 response due to the interference leading to a moderation of the pattern mid month on the EPS.

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

The MJO resumed its eastward propagation while greatly strengthening in amplitude over the Western

Pacific during the past week.

• RMM observations currently show the signal at greater than 3 standard deviations in amplitude,

the highest registered since March, 2024

• Based on objectively wave filtered upper-level velocity potential anomalies, the recent strengthening is

likely tied to higher frequency wave modes constructively interfering with both the enhanced and

suppressed MJO envelopes.

• The strong Western Pacific MJO has led to a weakening of the La Nina background circulation over the

equatorial Pacific, with convective anomalies developing off the equator.

• As the faster propagating tropical variability moves away of the slower MJO envelopes, a transition

towards more competing interference is favored, resulting in a substantially weakened MJO signal over

the Western Hemisphere during the next two weeks.

• Even with a weakened MJO, subseasonal forcing still favors the greatest chances for tropical cyclone

development over the South Pacific, with lowered chances over the Indian Ocean.

• The extratropical response associated with Western Hemisphere MJO events during December

historically consists of development of high latitude blocking over/near Greenland, potentially allowing for

Arctic air to be advected into portions of the central and eastern CONUS.

[A-L-E-K]

10 hours ago, MJO812 said:

ready 2 b buried

[MJO812]

52 minutes ago, A-L-E-K said:

ready 2 b buried

Same

[EasternLI]

I think this whole process was slowed down a little by the original Kelvin wave coming in stronger than longer range guidance was suggesting. So a little after mid month now looks like a better bet. After that period of destructive interference this is a pretty nice look starting to show up. And with the next Kelvin wave about to constructively interfere with it just beyond this. 

[MJO812]

Latest Euro Weeklies MJO 

[schoeppeya]

12 hours ago, MJO812 said:

Not possible, I was told it was a foregone conclusion that the PV was going to be strong by mid month and we were going to torch. 

[PhiEaglesfan712]

-ENSO and deep -IOD usually favor a cool December, in comparison to the rest of the season. That was the case in 2016-17 and 2022-23. It's January and February when it really torches.

If December ends with <1 inch of snow, then the winter is in trouble. That's what happened at PHL, BWI, and DCA those winters. PHL got lucky with the March 2017 snowstorm, but the snow totals for those seasons are as follows:

PHL: 0.3 inches 2022-23

BWI: 3.0 inches 2016-17, 0.2 inches 2022-23

DCA: 3.4 inches 2016-17, 0.4 inches 2022-23

[GaWx]

GEFS AO forecasts:

Just 4 days ago (11/28 run), it was forecasting the AO to be at +0.7 on Dec 7th (only 9 days out):

 Today’s run (12/2) has the Dec 7th AO way down to -2.3 or 3.0 lower than the run from a mere 4 days ago:

 Thus, even the ensemble means when looking out just 8-10 days have recently been missing high latitude blocking. So, for the time being, I’m taking the 11-14 day progs with more of a grain than usual.