2024 ENSO= BoM / CPC have La Niña watch in effect

[Kingarabian]

I personally don't agree with CPC; I agree with the BoM assessment that El Nino ended in April. I understand BoM has a higher threshold for El Nino and thus take longer than CPC to declare an event but also sooner than CPC to end it.

Per the ENSO blog it was splitting hairs either way, analogous to an analyzed 135-kt system with a couple 140-kt sfmrs.

The latest weekly measurement, which comes from the OISSTv2 dataset, was 0.5 °C above average. Given that the El Niño threshold is 0.5 °C, the team decided we’re right on the edge of the transition to neutral conditions.

This is my reasoning: look at this then look me in the eye and tell me this is El Nino I understand why CPC did it tho

https://i.imgur.com/biG3oD9.png

In this scenario from the CPC, I'm getting classic Wxman57 vs the NHC vibes. A once potent TC at the end of its life, but still considered a TC despite visible satellite imagery no longer showing a closed center.

[Woofde]

I personally don't agree with CPC; I agree with the BoM assessment that El Nino ended in April. I understand BoM has a higher threshold for El Nino and thus take longer than CPC to declare an event but also sooner than CPC to end it.

Per the ENSO blog it was splitting hairs either way, analogous to an analyzed 135-kt system with a couple 140-kt sfmrs.

The latest weekly measurement, which comes from the OISSTv2 dataset, was 0.5 °C above average. Given that the El Niño threshold is 0.5 °C, the team decided we’re right on the edge of the transition to neutral conditions.

This is my reasoning: look at this then look me in the eye and tell me this is El Nino I understand why CPC did it tho

I agree with that as well. It may qualify as El nino using the 3 month average, but it's quickly swapping. They themselves even admit that the atmosphere is not in an El Nino state anymore.

From their blog:
"The atmospheric half of El Niño is harder to detect this month; most of the standard equatorial Pacific atmospheric indicators (rain and clouds over the tropical Pacific, trade winds and upper-level winds) were pretty close to average."

If you look at the SSTs through a relative lense (anomalies - global average) instead of an absolute one it's even clearer that it's over and rapidly transitioning.

We have an El nino only in name right now.

[weeniepatrol]

-snipped-

We have an El nino only in name right now.https://uploads.tapatalk-cdn.com/20240511/e6f2a2390adc6e51a1fa48a2454f75e2.jpg

Exactly. That's the thing the atmosphere collectively looks like the ocean. I'd understand if there was WWBs or evidence of a low-frequency convective signal over the Pacific, still. But instead, its oops all trades and low-frequency forcing over Africa/Indian.

[cycloneye]

The transition to Neutral / La Niña is going smoothly.

[Hurricane2022]

These are the changes observed in the last 80d (Feb - May)

[Yellow Evan]

Global mean SSTA anomalies shows a cold tongue off South America extending into the East Pacific, though one could argue that that’s not a great metric to determine when an El Niño ends because the El Niño itself tends to cause global warming. Convective and trade wind patterns haven’t been like El Niño for at least a month.

[cycloneye]

Officially, ENSO is at warm neutral on the weekly update at +0.3C, but the anouncement on the transition from El Niño to Neutral will come on the June 13 update. The ONI is down to +1.1C. LarryWx, how is the data on the RONI?

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

[Hurricane2022]

 https://twitter.com/BOM_au/status/1790251243689959499

[chaser1]

The above graphic/statement does not seem to imply "fast developing" La Nina to me. Not to suggest that it won't occur, just pointing out that by the time that it does come along with the typical downstream pattern impact delay that the extent of impact to the Atlantic Hurricane season might be a bit more muted. Whatever NINA conditions start to evolve (such as decrease in upper-level wind shear perhaps), may result in enhanced favorable conditions that will primarily affect September, October & November development. That is not to say that the upcoming season won't be gangbuster nonetheless but could imply one element that could verify and infer slightly fewer storms then the big numbers broadly forecast. That or, perhaps not as high a ceiling for #'s of hurricanes, or # of majors. The obvious thing that is scary here is when looking back at last year which seemed a clear-cut battle of SST's verses El Nino, 2024 should not have that Godzilla vs King Kong battle of prevailing conditions. A largely neutral ENSO should at minimum suggest a less hostile upper-level wind regime. Whether other unforeseen inhibiting factors crop up such as above average surface pressures, dry mid-level conditions, or lagging early season El Nino upper level shear remain to be seen.

[JetFuel_SE]

The above graphic/statement does not seem to imply "fast developing" La Nina to me. Not to suggest that it won't occur, just pointing out that by the time that it does come along with the typical downstream pattern impact delay that the extent of impact to the Atlantic Hurricane season might be a bit more muted. Whatever NINA conditions start to evolve (such as decrease in upper-level wind shear perhaps), may result in enhanced favorable conditions that will primarily affect September, October & November development. That is not to say that the upcoming season won't be gangbuster nonetheless but could imply one element that could verify and infer slightly fewer storms then the big numbers broadly forecast. That or, perhaps not as high a ceiling for #'s of hurricanes, or # of majors. The obvious thing that is scary here is when looking back at last year which seemed a clear-cut battle of SST's verses El Nino, 2024 should not have that Godzilla vs King Kong battle of prevailing conditions. A largely neutral ENSO should at minimum suggest a less hostile upper-level wind regime. Whether other unforeseen inhibiting factors crop up such as above average surface pressures, dry mid-level conditions, or lagging early season El Nino upper level shear remain to be seen.

They're basing their statement on their own model, which has a solid degree's worth of warm bias.

[cycloneye]

La Niña comming very soon.

[zzzh]

 https://x.com/AndyHazelton/status/1791244423226884280

[LarryWx]

Officially, ENSO is at warm neutral on the weekly update at +0.3C, but the anouncement on the transition from El Niño to Neutral will come on the June 13 update. The ONI is down to +1.1C. LarryWx, how is the data on the RONI?

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

https://i.imgur.com/gBYwBvf.jpeg

Luis,
Sorry, I jut saw your question. While FMA ONI was +1.15, FMA RONI was already down to +0.48. Weeklies don't exist for RONI. But based on this FMA difference and assuming the difference is currently similar, an equivalent current RONI weekly would likely be -0.2 to -0.4 (cold neutral).

[cycloneye]

Officially, ENSO is at warm neutral on the weekly update at +0.3C, but the anouncement on the transition from El Niño to Neutral will come on the June 13 update. The ONI is down to +1.1C. LarryWx, how is the data on the RONI?

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

https://i.imgur.com/gBYwBvf.jpeg

Luis,
Sorry, I jut saw your question. While FMA ONI was +1.15, FMA RONI was already down to +0.48. Weeklies don't exist for RONI. But based on this FMA difference and assuming the difference is currently similar, an equivalent current RONI weekly would likely be -0.2 to -0.4 (cold neutral).

Yikes, already at cold neutral. Thanks as always.

[Category5Kaiju]

Question: given current trends and historic ENSO behavior, could we safely state yet that this will likely end up being a multi-year La Nina?

[LarryWx]

Question: given current trends and historic ENSO behavior, could we safely state yet that this will likely end up being a multi-year La Nina?

6 of the last 8 cases back to the late 1800s of strong+ Nino followed by Niña then had a second Niña. However, only 3 of 12 weak to mod Nino’s (and 0 of 7 mod, alone) followed by Niña had a 2nd Niña. Based on RONI, 23-4 Nino was high end mod.

OTOH, 10 of last 14 Niñas (and 5 of last 6) were 2+ years.
Based on that and stats for Niña followed by Nino, I’m going 75% chance of at least a double Niña coming up.

[NotSparta]

Question: given current trends and historic ENSO behavior, could we safely state yet that this will likely end up being a multi-year La Nina?

Coming out of a super El Nino in a Pacific under the iron grip of -PDO, I imagine La Nina will stick around for 2025

[Blown Away]

Question: given current trends and historic ENSO behavior, could we safely state yet that this will likely end up being a multi-year La Nina?

6 of the last 8 cases back to the late 1800s of strong+ Nino followed by Niña then had a second Niña. However, only 3 of 12 weak to mod Nino’s (and 0 of 7 mod, alone) followed by Niña had a 2nd Niña. Based on RONI, 23-4 Nino was high end mod.

OTOH, 10 of last 14 Niñas (and 5 of last 6) were 2+ years.
Based on that and stats for Niña followed by Nino, I’m going 75% chance of at least a double Niña coming up.

Larry, the timing of the cold neutral into hurricane season and likely moderate Nina into ASO seems to significantly increase the chances for a hurricane for NE Caribbean, SE Bahamas, and SFL. Many of the big storms for these areas occurred under a similar setup and the wildcard are these epic SST’s. Don’t you think there is a likelihood of a big impact in these areas??

[LarryWx]

Question: given current trends and historic ENSO behavior, could we safely state yet that this will likely end up being a multi-year La Nina?

6 of the last 8 cases back to the late 1800s of strong+ Nino followed by Niña then had a second Niña. However, only 3 of 12 weak to mod Nino’s (and 0 of 7 mod, alone) followed by Niña had a 2nd Niña. Based on RONI, 23-4 Nino was high end mod.

OTOH, 10 of last 14 Niñas (and 5 of last 6) were 2+ years.
Based on that and stats for Niña followed by Nino, I’m going 75% chance of at least a double Niña coming up.

Larry, the timing of the cold neutral into hurricane season and likely moderate Nina into ASO seems to significantly increase the chances for a hurricane for NE Caribbean, SE Bahamas, and SFL. Many of the big storms for these areas occurred under a similar setup and the wildcard are these epic SST’s. Don’t you think there is a likelihood of a big impact in these areas??

The research I did was for CONUS landfalls overall. It showed that on RONI basis, the highest risk vs climo for one’s area ON AVG is especially when ASO is -0.5 to -1.0 with closer to avg risk for one’s area when it is already below -1.0. With RONI likely already down to -0.2 to -0.4 and with Aug still 2.5 months away, the odds favor below -1.0 for ASO or thus close to avg risk for CONUS landfalls overall.

Out of curiosity to see if there was a suggestion of an agreement with this finding, I decided to look at CONUS precip anomalies map for ASO for seasons with ASO RONI -0.5 to -1.0 vs seasons with sub -1.0:

Here’s precip anomalies for ASO RONI -0.5 to -1.0:

https://psl.noaa.gov/cgi-bin/data/uscli ... reate+Plot

Notice that the wettest anomalies are concentrated from FL peninsula up the E coast with dry to the west of the wetness stretching from TX to the N and NE

Now, here’s precip anomalies for ASO RONI sub -1.0:

https://psl.noaa.gov/cgi-bin/data/uscli ... reate+Plot

Notice that the wettest anomalies go from FL Panhandle westward to SE 1/3 of TX with the dryness further west in W/NW TX N to NB and W into SW US. The FL pen and up E seaboard averages out NN.

So, these maps suggest the tendency for storms to move into the FL pen and/or go up the E coast (i.e., some recurvature tendency near the E coast) for ASO RONI -0.5 to -1.0 vs tendency of further W most active storm track N or NW into Gulf coast with subsequent N movement inland for ASO RONI sub -1.0.

Interesting! This seems to imply the mean steering high is centered further west and/or stronger when La Niña is stronger during ASO. Does this make sense?

RONI: https://www.cpc.ncep.noaa.gov/data/indi ... .ascii.txt

*Edited for modifications

[dexterlabio]

The last moderate-strong El Niño during -PDO was followed by a double dip La Niña and two cold neutral years. If I have to bet, La Niña/cold neutral will stay for quite a while, until the next potent El Niño (say 4-5 years from now) attempts to flip the PDO positive.