ENSO Discussion

[stuffradio]

Looks like others are thinking it's peaked too.

 

 

There's a changing of the guards regarding which location on the planet features the most anomalous forcing in the tropics. The El Nino standing wave is weakening in the appended December-January forecast, suggesting that El Nino has peaked in amplitude.

https://twitter.com/MJVentrice/status/1067528103344390145

[Brian_in_Leavenworth]

Looks like others are thinking it's peaked too.

Interesting, since Ventrice has been very bullish on El Nino this year.

[Webberweather53]

Ahh yes right on cue, a few days after OISSTv2 weeklies are ~+1.3C, CDAS is finally starting to catch up a few days later, similar to last month's NINO 3.4 spike.

 

[Front Ranger]

SON should finish +.6 to .7. 

 

The strongest any Nino has peaked with a SON of .7 or lower is 1.1 (low end moderate), which happened in both 1968 and 1994.

[TigerWoodsLibido]

SON should finish +.6 to .7. 

 

The strongest any Nino has peaked with a SON of .7 or lower is 1.1 (low end moderate), which happened in both 1968 and 1994.

 

Those analogs are nice.

[stuffradio]

Ahh yes right on cue, a few days after OISSTv2 weeklies are ~+1.3C, CDAS is finally starting to catch up a few days later, similar to last month's NINO 3.4 spike.

 

Looks like it's dipping again, right on queue.

[stuffradio]

The ENSO 3.4 region is dipping back down again still. I could see it going back to neutral.

[Webberweather53]

Weekly OISSTv2 dropped slightly but is at +1.2C, CDAS isn't really dipping back down either.

[Phil]

Why has OISSTv2 been running warmer than both HADISST and CDAS this year?

[Phil]

Looks like that prolonged WWB on the EPS weeklies (the one we debated over a few weeks ago) turned to be just another intraseasonal pass.

 

[Geos]

Big time cooling in ENSO region 1+2.

 

 

[Front Ranger]

Weekly OISSTv2 dropped slightly but is at +1.2C, CDAS isn't really dipping back down either.

 

The one-sided nature of your posts here may be starting to hurt your credibility. You seem dead-set on this event becoming significant, despite that looking increasingly unlikely.

[Webberweather53]

The one-sided nature of your posts here may be starting to hurt your credibility. You seem dead-set on this event becoming significant, despite that looking increasingly unlikely.

 

That's ironic considering everyone else here is wishcasting for neutral ENSO or a La Nina it seems lol. You don't get +3 sigma AAM anomalies like this w/ "insignificant" ENSO events. Correct me if I'm wrong, but I did in fact call for a weak-moderate El Nino (based on SSTAs) to develop this winter as early as July and that's appearing to transpire atm.

[Phil]

Is the extremely high integral of AAM solely a function of ENSO, though?

 

I think the QBO/MQI constraining convection closer to the equator, along with the cycle of eddy transport of said westerly momentum poleward from the subtropics, is actually more to blame for the high AAM anomaly than the ENSO state (which is barely even discernible in the low pass VP200 anomalies, at this point).

[Webberweather53]

NOAA ERSSTv5 Oceanic Nino Index for SON was ~ +0.7C, this dataset has been reasonably close to the ENS ONI mean of late.

[Webberweather53]

Is the extremely high integral of AAM solely a function of ENSO, though?

 

I think the QBO/MQI constraining convection closer to the equator, along with the cycle of eddy transport of said westerly momentum poleward from the subtropics, is actually more to blame for the high AAM anomaly than the ENSO state (which is barely even discernible in the low pass VP200 anomalies, at this point).

 

This is a loaded question, of course it's not solely a function of ENSO, but you don't get strong, persistent +AAM anomalies like that without there being constructive ENSO interference to supplant the momentum, if we had a NINA/eQBO we may not even high that much +AAM to begin with you need both ENSO and the stratosphere to cooperate to generate the observed behavior we've seen lately.

[Phil]

For instance, the cool season of 1985/86 also put up some outrageously high AAM anomalies, and that was a cold neutral/weak niña year. November of 1985 was particularly insane in that regard.

 

As you said, AAM is complicated..you sort of have to spatially decode it to figure out what it’s actually telling you.

[Webberweather53]

For instance, the cool season of 1985/86 also put up some outrageously high AAM anomalies, and that was a cold neutral/weak niña year. November of 1985 was particularly insane in that regard.

 

As you said, AAM is complicated..you sort of have to spatially decode it to figure out what it’s actually telling you.

 

1985-86 was strong but did so w/o any help from eQBO shear or ENSO early in the winter.

[Webberweather53]

1985-86 was strong but did so w/o any help from eQBO shear or ENSO early in the winter.

 

Oth, I'm sure having a beefy +PDO in the background helps a lot

[Phil]

We have the ENSO component (which was stronger during the early autumn), and the communicative feedbacks which arise from it (and are reinforced via extratropical/looping conduits).

 

In this case, note the poleward propagation of +AAM via eddy transports w/ low latitude inception. That’s clearly QBO/MQI preconditioned, IMO.

 

[Webberweather53]

We have the ENSO component (which was stronger during the early autumn), and the peripherals which arise from it and are reinforced via extratropical/looping conduits.

 

In this case, note the poleward propagation of +AAM via eddy transports w/ low latitude inception. That’s clearly QBO/MQI preconditioned, IMO.

 

 

It's nice to see how intraseasonal forcing finally instigated the poleward AAM propagation here, you can already see a new westerly regime building in the tropics, it's also possible this one gets refracted back towards the equator. I'm honestly pretty curious to see how the overall system and tropical forcing alike responds to the considerable wave 1 fluxes onto the PV in the coming weeks. We're starting from a warmer base state than last year's split event in Feb 2018 (which arguably helped trigger the initial downwelling OKW thereafter in the Eq Pacific)

[Front Ranger]

That's ironic considering everyone else here is wishcasting for neutral ENSO or a La Nina it seems lol. You don't get +3 sigma AAM anomalies like this w/ "insignificant" ENSO events. Correct me if I'm wrong, but I did in fact call for a weak-moderate El Nino (based on SSTAs) to develop this winter as early as July and that's appearing to transpire atm.

I don't think people in this thread have been wish casting a Nina or neutral. Weak +ENSO seems to be the consensus.

[Webberweather53]

It's nice to see how intraseasonal forcing finally instigated the poleward AAM propagation here, you can already see a new westerly regime building in the tropics, it's also possible this one gets refracted back towards the equator. I'm honestly pretty curious to see how the overall system and tropical forcing alike responds to the considerable wave 1 fluxes onto the PV in the coming weeks. We're starting from a warmer base state than last year's split event in Feb 2018 (which arguably helped trigger the initial downwelling OKW thereafter in the Eq Pacific)

 

It still amazes me to see how strong the links between these extratropical basic state changes in the preceding winter are to state dependent noise forcing before the spring predictability barrier.

[Phil]

It's nice to see how intraseasonal forcing finally instigated the poleward AAM propagation here, you can already see a new westerly regime building in the tropics, it's also possible this one gets refracted back towards the equator. I'm honestly pretty curious to see how the overall system and tropical forcing alike responds to the considerable wave 1 fluxes onto the PV in the coming weeks. We're starting from a warmer base state than last year's split event in Feb 2018 (which arguably helped trigger the initial downwelling OKW thereafter in the Eq Pacific)

I’m interested in the potential SSW as well, since it would profoundly interfere w/ the long term cycle of resonance in the tropical forcing/momentum transfer (we’re actually leaving the eQBO/narrow Hadley Cell regime now, as evidenced by the poleward propagation of +AAM, so a SSW would throw a massive wrench into what would otherwise be a fairly rhythmic pendulum).

[Phil]

It still amazes me to see how strong the links between these extratropical basic state changes in the preceding winter are to state dependent noise forcing before the spring predictability barrier.

I don’t know if you saw it, but the inception of the STJ/subtropical +AAM load late last summer was almost perfectly synchronized w/ the easterly downwell to the tropical tropopause. One of the more impressive cases I’ve seen, tbh.

[Webberweather53]

I’m interested in the potential SSW as well, since it would profoundly interfere w/ the long term cycle of resonance in the tropical forcing/momentum transfer (we’re actually leaving the eQBO/narrow Hadley Cell regime now, as evidenced by the poleward propagation of +AAM, so a SSW would throw a massive wrench into what would otherwise be a fairly rhythmic pendulum).

 

Ugh, I'm actually starting to get used to this eQBO/narrow Hadley Cell regime, would be nice if we get a momentary extension & reinvigoration of the BDC later into the winter.

[Phil]

I saved these images from October 2nd. This was epic..very little vertical/interhemispheric disconnect.

 

30mb 50mb 100mb 200mb

 

[Phil]

[Webberweather53]

I’m with you there, lol. It was nice to finally have a cool mid/late autumn and early season snowfall. Stuff like that is once in a blue moon nowadays until Feb-Apr.

 

I'm potentially staring down the barrel of one in the coming days, hard to not have tunnel vision beyond this given the rarity of seeing potential winter storms this early in my neck of the woods.

[Phil]

[Phil]

So far, so good.

 

[Front Ranger]

Full context matters. 

 

 

It doesn’t look like a coherent MJO to me. Technically a wave-2 structure there (waves in W-IO & Pacific), with Indo-Pacific subsidence (which is more niño-esque). That said, November could be decent in the West due to the retracting jet/AAM deposition by Eurasia, with the poleward propagation via eddy transports becoming evident as well.

This feels like something that would end up tightening the vortex into December, though. Don’t really expect big cold anywhere in the USA until after New Years, at this point.

 

 

I disagree. I think there's a good shot at a major cold wave into the U.S. in mid November, and another one by late December.

 

 

I guess we’ll see. I envision a run-of-the-mill cool pattern morphing into a zonal pattern by December with a strong vortex.

 

 

I don't see any pattern locking in for long over the next couple months. More variability than usual.

 

 

There was a major cold wave into the U.S. in mid November. Definitely pattern variability overall. We'll see if the late December major cold wave happens.

 

To your credit, it does look like a zonal pattern developing this month for a bit, so you got that part right.

[Phil]

The November cold wasn’t all that extraordinary, though. Didn’t even come close to 2014, let alone the big dogs back in the 1980s.

 

Henceforth, I think “run of the mill cold pattern” is a more fitting description. Though maybe it was somewhat more intense than I originally thought.

[Front Ranger]

The November cold wasn’t all that extraordinary, though. Didn’t even come close to 2014, let alone the big dogs back in the 1980s.

 

Henceforth, I think “run of the mill cold pattern” is a more fitting description. Though maybe it was somewhat more intense than I originally thought.

 

Right...only brought some of the earliest snowfalls on record to some places and weekly anomalies in the -15 to -20 range.

 

If that didn't qualify as a major cold wave, then apparently only a once in decades one does. 

[Phil]

Right...only brought some of the earliest snowfalls on record to some places and weekly anomalies in the -15 to -20 range.

 

If that didn't qualify as a major cold wave, then apparently only a once in decades one does.

In terms of the anomalies for the month, it certainly wasn’t extraordinary. That cold shot into the Deep South during the middle of the month was very impressive, though.

[Front Ranger]

In terms of the anomalies for the month, it certainly wasn’t extraordinary. That cold shot into the Deep South during the middle of the month was very impressive, though.

 

You're changing the goal posts. I never said it would be an extraordinarily cold month, I predicted a major cold wave in mid November. That did occur, as you just admitted.

[ShawniganLake]

You're changing the goal posts. I never said it would be an extraordinarily cold month, I predicted a major cold wave in mid November. That did occur, as you just admitted.

Wasn’t it the coldest thanksgiving in more than a century in the NE.

[Front Ranger]

Just one of many examples from the cold wave in the middle of the country this past month. St. Louis, MO with the daily departures bolded.

 

9 37 23 30 -20 
10 35 18 27 -23 
11 45 29 37 -12 
12 40 27 34 -15 
13 28 20 24 -24 
14 32 17 25 -23 
15 35 28 32 -15

 

Add it up and you have a weekly departure of about -19.

[Front Ranger]

Wasn’t it the coldest thanksgiving in more than a century in the NE.

 

Not sure. There were multiple notable cold shots in November, but the one that affected the largest area for the longest time was the one from around the 10th to the 15th in the middle of the CONUS.

[BLI snowman]

Wasn’t it the coldest thanksgiving in more than a century in the NE.

 

Boston had its coldest November high since 1901. Portland had its coldest November high since 1875. It was an extremely impressive cold shot for New England.