2024 ENSO Updates

[Kingarabian]

Cool neutral is almost the same as weak la niña for the NATL as the hurricane season will still be very active with Caribbean activity.

The outlook has gotten more ominous per data I've seen with the RONI not looking as strong. Per the July Euro after bias correction, it is predicting ASO RONI of near -0.8. If that or something nearby were to verify, that along with Beryl and the near record warm Atlantic would be an ominous indicator for the heart of the season in an area stretching from the NE Caribbean to the SE US. Of course, much of this region along with TX/NE MX has already been very active.

But it being an ominous indicator for the heart doesn't mean it will be as the RONI based stats are based on averages with lots of variability.

It also could allow the EPAC to become active and behave more like 2016 than 2010. EPAC activity could have implications on the Atlantic.

[cycloneye]

We have a delay of La Niña but eventually, will be present in the August thru October period.

Extract of update:

https://www.cpc.ncep.noaa.gov/products/ ... disc.shtml

Compared to the previous month, the most recent IRI plume delayed the emergence of La Niña to September-November 2024, with La Niña then persisting through the Northern Hemisphere winter [Fig. 6]. The forecast team is also favoring a delayed development of La Niña this month, but is anticipating the transition to occur earlier (August-October). This is, in part, supported by the continuation of below-average subsurface ocean temperatures and near-term forecasts suggesting a resurgence of easterly wind anomalies in July. In summary, ENSO-neutral is expected to continue for the next several months, with La Niña favored to emerge during August-October (70% chance) and persist into the Northern Hemisphere winter 2024-25 (79% chance during November-January)

[cycloneye]

Phil Klotzbach shows La Niña coming very soon.

 https://x.com/philklotzbach/status/1811407535292702794

[cycloneye]

Here is the ENSO Blog where a more detailed discussion about the update is made.

https://www.climate.gov/news-features/b ... r-vacation

[cycloneye]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

[USTropics]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

I'm with LarryWx and Ben Noll on this one, I think it's difficult to compare ENSO events using ONI given the current climo and the background climate change signals. Instead of using a 30-year climo period average, RONI focuses more on the tropical domain (20N to 20S). This has been shown to better capture SST gradient changes that drive the Walker circulation (and thus, is better at diagnosing atmosphere-ocean coupling imo). Here is the latest forecast from Ben Noll:

[LarryWx]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

The latest model consensus for early July, despite the slightly warmer Euro, is actually cooler:

Summary of latest SON ONI forecasts (subtract ~0.5 to estimate RONI):

Euro: warmed 0.2 to ~-0.1 (has a longterm warm bias/slightly too warm last year but warm bias stronger when non-Nino)

BoM: cooled 0.3 to ~-0.2 (huge warm bias last year)

MeteoFrance: cooled 0.5 to ~-0.4 (strong warm bias)

JMA: cooled 0.3 to ~-0.8 (no known significant bias/did well last year)

UKMET: cooled 0.1 to ~-1.0 (did best last year/no known significant bias)

CFS: warmed 0.1 to ~-1.1 (overall limited accuracy; I think it has cool bias)

So, with the significantly cooler JMA/MeteoFrance, I’m thinking the chances for a solid weak La Niña per ONI are increasing again (vs cold neutral). This also means the chances for a moderate La Niña per RONI are increasing again (vs weak).

If we can get a stronger moderate (say -1.2 to -1.4) as opposed to just weak La Niña based on RONI for ASO, it MIGHT lead to a slight reduction in the risk for the rest of the season for H hits for the area from the E Caribbean to the E Gulf/SE US vs what I thought a week ago.

Based on longterm averages, the highest risk for that corridor is when ASO is ~-1.0/-1.1 to ~-0.5. In last week’s post I had said it was looking very ominous for E Car. to SE US due to what appeared to be a -0.8ish ASO RONI in combination with the very warm Atlantic and what Beryl portends. But if ASO RONI were to instead be, say -1.2 to -1.4, that might lead to a suppression of many W Atlantic basin tracks from the NW Caribbean into C America/MX/S TX like was the case in 2010 (which wouldn’t be good for them obviously but wouldn’t be as bad from NE Car to SE US). But even so, this is only based on averages and the Atlantic is near record warm. So, it could still end up bad even with a moderate RONI based Niña in ASO.

[weeniepatrol]

the easterlies didn't get the memo

[Kingarabian]

the easterlies didn't get the memo

https://i.imgur.com/KRD4uh1.png

July trades never fail. Just need to see some reflection in the SSTs over the Nino regions.

[Kingarabian]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

I'm with LarryWx and Ben Noll on this one, I think it's difficult to compare ENSO events using ONI given the current climo and the background climate change signals. Instead of using a 30-year climo period average, RONI focuses more on the tropical domain (20N to 20S). This has been shown to better capture SST gradient changes that drive the Walker circulation (and thus, is better at diagnosing atmosphere-ocean coupling imo). Here is the latest forecast from Ben Noll:

https://i.imgur.com/K0Dla3q.png

The only thing that's giving me some pause is that the SOI most recently was more reflective of the ONI vs RONI.

[Kingarabian]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

Because it's almost mid July and the weeklies remain warm, I think cool neutral is most likely for ASO. We'll probably see a weak La Nina for the winter though.

[toad strangler]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

The latest model consensus for early July, despite the slightly warmer Euro, is actually cooler:

Summary of latest SON ONI forecasts (subtract ~0.5 to estimate RONI):

Euro: warmed 0.2 to ~-0.1 (has a longterm warm bias/slightly too warm last year but warm bias stronger when non-Nino)

BoM: cooled 0.3 to ~-0.2 (huge warm bias last year)

MeteoFrance: cooled 0.5 to ~-0.4 (strong warm bias)

JMA: cooled 0.3 to ~-0.8 (no known significant bias/did well last year)

UKMET: cooled 0.1 to ~-1.0 (did best last year/no known significant bias)

CFS: warmed 0.1 to ~-1.1 (overall limited accuracy; I think it has cool bias)

So, with the significantly cooler JMA/MeteoFrance, I’m thinking the chances for a solid weak La Niña per ONI are increasing again (vs cold neutral). This also means the chances for a moderate La Niña per RONI are increasing again (vs weak).

If we can get a stronger moderate (say -1.2 to -1.4) as opposed to just weak La Niña based on RONI for ASO, it MIGHT lead to a slight reduction in the risk for the rest of the season for H hits for the area from the E Caribbean to the E Gulf/SE US vs what I thought a week ago.

Based on longterm averages, the highest risk for that corridor is when ASO is ~-1.0/-1.1 to ~-0.5. In last week’s post I had said it was looking very ominous for E Car. to SE US due to what appeared to be a -0.8ish ASO RONI in combination with the very warm Atlantic and what Beryl portends. But if ASO RONI were to instead be, say -1.2 to -1.4, that might lead to a suppression of many W Atlantic basin tracks from the NW Caribbean into C America/MX/S TX like was the case in 2010 (which wouldn’t be good for them obviously but wouldn’t be as bad from NE Car to SE US). But even so, this is only based on averages and the Atlantic is near record warm. So, it could still end up bad even with a moderate RONI based Niña in ASO.

2010 is a CSU analog from their update two days ago. As I’m sure you are aware of!

[USTropics]

LarryWx, Kingarabian , Yellow Evan What are your takes on this CPC July update? Anyone apart from those 3 members can chime in.

I'm with LarryWx and Ben Noll on this one, I think it's difficult to compare ENSO events using ONI given the current climo and the background climate change signals. Instead of using a 30-year climo period average, RONI focuses more on the tropical domain (20N to 20S). This has been shown to better capture SST gradient changes that drive the Walker circulation (and thus, is better at diagnosing atmosphere-ocean coupling imo). Here is the latest forecast from Ben Noll:

https://i.imgur.com/K0Dla3q.png

The only thing that's giving me some pause is that the SOI most recently was more reflective of the ONI vs RONI.

TBF the SOI has been on a monthly pendulum swing this year:


Another complication with climate change is that both Tahiti and Darwin lie south of the equator. There was a recent research paper published that using the Equatorial Oscillation Index is a better tool now:
https://ui.adsabs.harvard.edu/abs/2020JMetR..34.1025S/abstract
https://www.cpc.ncep.noaa.gov/data/indices/

[weeniepatrol]

Rip and tear

[cycloneye]

No important changes to the data on this week's CPC update.

The latest weekly
SST departures are:
Niño 4 +0.7ºC
Niño 3.4 +0.3ºC
Niño 3 -0.1ºC
Niño 1+2 -0.2ºC

https://www.cpc.ncep.noaa.gov/products/ ... ts-web.pdf

[Kingarabian]

Buoys show +1C t/+2C anomalies from the dateline to 90W, extending to about 100meters deep at the subsurface.

GODAS/PENTAD show -2C anomalies continuing to erupt in the EPAC. Two different climo datasets painting a different subsurface picture.

[LarryWx]

Buoys show +1C t/+2C anomalies from the dateline to 90W, extending to about 100meters deep at the subsurface.

GODAS/PENTAD show -2C anomalies continuing to erupt in the EPAC. Two different climo datasets painting a different subsurface picture.

Indeed, buoys 2N to 2S continue to measure a very stubborn warm layer down to ~100m above a La Ninaish cold layer below. Seems highly unusual. Will that warm later ever be pushed out? It is like a weak Nino lying just above a solid Niña (2N to 2S, not 5N to 5S).

[Kingarabian]

MJO is in the region but there are some strong daily negatives on the SOI this week. Has pushed the 30 day SOI back in negative territory.

[LarryWx]

MJO is in the region but there are some strong daily negatives on the SOI this week. Has pushed the 30 day SOI back in negative territory.

They’re about bottoming now and should head back up shortly. What’s been driving the recent strong -SOI days have been very high Darwin SLPs. For those who don’t follow the SOI closely, a developing La Niña favors +SOIs in late spring and especially summer+. AN Tahiti SLP and BN Darwin SLP correlates to +SOI.

But recent Darwin SLPs have been anything but low. On the contrary, we just had 2 days of 1017.55+ with today in highly rarified territory at 1017.85. How rare is 1017.85?

Since 1991 and prior to today, there had been only 4 days with Darwin SLP of 1017.85+:

1018.35: June 22, 2004
1017.90: July 25, 2023
1017.90: Aug 5, 2023
1017.85: Aug 12, 1994

Note that all of these other 4 1017.85+ Darwin days were during an incoming or already existent 1st year El Niño. That’s far from the case now.

Since 1991 there’s been only one day during a year with a first year Niña immediately following a Nino that had a Darwin SLP >1017 mb: the 1017.15 mb of Aug 12, 1995.

For Niña following Nino, highest daily Darwin SLP:

1995: 1017.15
1998: 1015.35
2005: 1016.00
2007: 1016.00
2010: 1014.65
2016: 1015.25

[dexterlabio]

It seemed easier for La Nina to develop rapidly this summer with the negative PDO, also climo favors La Nina following right after a moderate to strong El Nino. At this point in ENSO we are still in the warm neutral phase, and it may take some time to dive into cool neutral.