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Re: ENSO Updates

#11441 Postby cycloneye » Mon Apr 27, 2020 8:35 am

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Re: ENSO Updates

#11442 Postby cycloneye » Mon Apr 27, 2020 8:42 am

WeatherEmperor wrote:
Kingarabian wrote:
cycloneye wrote:Big blue comming.

[url]https://i.imgur.com/Y2TTRZi.jpg[url]

Let's see if it verifies. Remember the CFS is based off the GFS. These trades need to verify this strong to get that fall blown La Nina by ASO that the CFS forecasts.

BOM had Nino 3.4 @ +0.53C this week. I'm assuming the CPC will do the same.


Looks like 3.4 came in at +0.6C for today's update. Do you have any of the latest sub-surface maps?


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Cooling Ocean Heat Anomalies.

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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11443 Postby cycloneye » Mon Apr 27, 2020 11:23 am

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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11444 Postby Kingarabian » Mon Apr 27, 2020 3:13 pm

We'll likely be seeing a sizeable trade burst that will trigger a new downwelling Kelvin wave. Then models agree on an extended period of relaxed trades across the Pacific. So it's going to be a gradual process but it'll get there.

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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11445 Postby cycloneye » Mon Apr 27, 2020 4:17 pm

Kingarabian wrote:We'll likely be seeing a sizeable trade burst that will trigger a new downwelling Kelvin wave. Then models agree on an extended period of relaxed trades across the Pacific. So it's going to be a gradual process but it'll get there.

https://i.imgur.com/9MgHhRY.png


Extended period? How much will be that period?
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11446 Postby Kingarabian » Mon Apr 27, 2020 4:24 pm

cycloneye wrote:
Kingarabian wrote:We'll likely be seeing a sizeable trade burst that will trigger a new downwelling Kelvin wave. Then models agree on an extended period of relaxed trades across the Pacific. So it's going to be a gradual process but it'll get there.

https://i.imgur.com/9MgHhRY.png


Extended period? How much will be that period?

Till about the end of May it looks like. Though this can easily change though and even if it does verify it will just slow the cooling of the surface temperatures for a little longer. The main player will be a new downwelling Kelvin wave near the dateline that will keep the subsurface cool well into the summer.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11447 Postby cycloneye » Mon Apr 27, 2020 5:24 pm

Kingarabian wrote:
cycloneye wrote:
Kingarabian wrote:We'll likely be seeing a sizeable trade burst that will trigger a new downwelling Kelvin wave. Then models agree on an extended period of relaxed trades across the Pacific. So it's going to be a gradual process but it'll get there.

https://i.imgur.com/9MgHhRY.png


Extended period? How much will be that period?

Till about the end of May it looks like. Though this can easily change though and even if it does verify it will just slow the cooling of the surface temperatures for a little longer. The main player will be a new downwelling Kelvin wave near the dateline that will keep the subsurface cool well into the summer.


If that happens,there will not be La Niña for ASO and also that could bust the expert forecasts and they may have to do changes to the down side. I have seen some doom and gloom things in some forecasts like Weatherbell, WeatherTiger among those. We will see in real time what will occur with ENSO in the comming months.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11448 Postby aspen » Mon Apr 27, 2020 6:24 pm

cycloneye wrote:
Kingarabian wrote:
cycloneye wrote:
Extended period? How much will be that period?

Till about the end of May it looks like. Though this can easily change though and even if it does verify it will just slow the cooling of the surface temperatures for a little longer. The main player will be a new downwelling Kelvin wave near the dateline that will keep the subsurface cool well into the summer.


If that happens,there will not be La Niña for ASO and also that could bust the expert forecasts and they may have to do changes to the down side. I have seen some doom and gloom things in some forecasts like Weatherbell, WeatherTiger among those. We will see in real time what will occur with ENSO in the comming months.

It’s still going to be a cooler ENSO and not an El Niño — that’s the important thing, whether we get a La Niña for ASO or not.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11449 Postby CyclonicFury » Mon Apr 27, 2020 6:49 pm

aspen wrote:
cycloneye wrote:
Kingarabian wrote:Till about the end of May it looks like. Though this can easily change though and even if it does verify it will just slow the cooling of the surface temperatures for a little longer. The main player will be a new downwelling Kelvin wave near the dateline that will keep the subsurface cool well into the summer.


If that happens,there will not be La Niña for ASO and also that could bust the expert forecasts and they may have to do changes to the down side. I have seen some doom and gloom things in some forecasts like Weatherbell, WeatherTiger among those. We will see in real time what will occur with ENSO in the comming months.

It’s still going to be a cooler ENSO and not an El Niño — that’s the important thing, whether we get a La Niña for ASO or not.

Based on this graphic from WeatherTiger, neutral ENSO actually seems to have a higher average Atlantic ACE than a moderate/strong La Niña. As long as El Niño doesn't unexpectedly develop, I think an above-average season is likely.

Image
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11450 Postby Kingarabian » Mon Apr 27, 2020 6:51 pm

cycloneye wrote:
Kingarabian wrote:
cycloneye wrote:
Extended period? How much will be that period?

Till about the end of May it looks like. Though this can easily change though and even if it does verify it will just slow the cooling of the surface temperatures for a little longer. The main player will be a new downwelling Kelvin wave near the dateline that will keep the subsurface cool well into the summer.


If that happens,there will not be La Niña for ASO and also that could bust the expert forecasts and they may have to do changes to the down side. I have seen some doom and gloom things in some forecasts like Weatherbell, WeatherTiger among those. We will see in real time what will occur with ENSO in the comming months.


With the models showing a favorable global VP anomaly setup, to have cool-neutral and not La Nina IMO could be a worst case scenario. In the past twenty years two of the worst seasons in 2005 and 2017 had similar setups and also had cool-neutral instead of La NIna in place during ASO.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11451 Postby cycloneye » Mon Apr 27, 2020 6:59 pm

Thanks to Kingarabian , CyclonicFury and aspen.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11452 Postby CyclonicFury » Mon Apr 27, 2020 7:55 pm

It seems likely FMA finishes at least +0.5°C, which would be the fifth trimonthly in a row. I wonder if CPC will retroactively classify 2019-20 as a weak El Niño event.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11453 Postby DorkyMcDorkface » Mon Apr 27, 2020 8:09 pm

The latest Bureau of Meteorology (BOM) ENSO outlook shows the mean straddling the La Niña threshold for ASO (remember that the BOM's criteria for La Niña (El Niño) is lower (higher) than the CPC's). Also note that there are now very few ensemble members that remain in warm-neutral territory by then, and zero members that rise above the El Niño threshold.

Granted, as mentioned preiously, whether or not we get cool-neutral or weak La Niña conditions doesn't really matter as much as the fact that it's increasingly likely we won't be seeing an El Niño by the peak of the Atlantic hurricane season.

Image
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11454 Postby Shell Mound » Tue Apr 28, 2020 3:03 am

DorkyMcDorkface wrote:The latest Bureau of Meteorology (BOM) ENSO outlook shows the mean straddling the La Niña threshold for ASO (remember that the BOM's criteria for La Niña (El Niño) is lower (higher) than the CPC's). Also note that there are now very few ensemble members that remain in warm-neutral territory by then, and zero members that rise above the El Niño threshold.

Granted, as mentioned preiously, whether or not we get cool-neutral or weak La Niña conditions doesn't really matter as much as the fact that it's increasingly likely we won't be seeing an El Niño by the peak of the Atlantic hurricane season.

http://www.bom.gov.au/climate/ocean/outlooks/archive/20200425//plumes/sstOutlooks.nino34.hr.png

Historically, however, it does seem to matter, at least to a degree. (Note that even 2017 featured La Niña by the peak of the Atlantic hurricane season. If 2020 does not, then its ACE index will likely be substantially lower than that of 2017.) Additionally, if we end up with cool neutral or even plain neutral ENSO—as opposed to weak La Niña—by the peak of the Atlantic hurricane season in ASO, then we may also see a weaker subtropical ridge that results in more storms curving out to sea instead of striking the mainland U.S., given that the -PDO signature—which tends to favour West-Coast troughs and East-Coast ridges—typically tends to be less pronounced in neutral ENSO vs. La Niña. Given current oceanic-atmospheric trends, even weak Niña conditions seem unlikely by the peak of the hurricane season, so not only will the “hyperactive” (as opposed to slightly-above-average) forecasts likely bust on the high side, but the forecasts for steering currents may also prove incorrect.

The prediction is for 19.8 +/- 4.4 total named tropical cyclones, which corresponds to a range between 15 and 24 storms, with a best estimate of 20 named storms. ... If no La Niña develops (by the peak of the Atlantic hurricane season — ed.), then the prediction will be slightly lower: 18.3 +/- 4.3 storms (range of 14-23 storms, with a best guess of 19).

PSU’s 2020 ATL hurricane forecast

Note the significant drop in total NS (from 19.8 to 18.3) simply by having cool neutral ENSO instead of weak La Niña by ASO.
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Re: ENSO Updates

#11455 Postby cycloneye » Tue Apr 28, 2020 6:36 am

The BoM update of April 28:

Negative Indian Ocean Dipole possible in 2020
The El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) both remain neutral. Neutral ENSO conditions are likely to persist over the coming months, with some likelihood a La Niña-like state could develop in the tropical Pacific Ocean late in the southern hemisphere winter or spring (less than 50% chance). Most models suggest a negative IOD could develop in the Indian Ocean from mid-winter.

Atmospheric and oceanic indicators of ENSO including the Southern Oscillation Index (SOI), trade winds, cloudiness near the Date Line, and sea surface temperatures in the tropical Pacific Ocean generally persist at levels consistent with a neutral ENSO state. Sub-surface temperatures in the tropical Pacific Ocean have cooled over the past two months, indicating increased potential for cooling at the surface in the coming months under the right conditions.

Most climate models surveyed by the Bureau indicate that ENSO is likely to stay neutral through the southern hemisphere winter. By late winter/early spring, three of the eight climate models surveyed by the Bureau reach or exceed La Niña levels, while the remaining five stay neutral. ENSO predictions made during autumn tend to have lower accuracy than predictions made at other times of the year, so current ENSO forecasts should be used with some caution. The Bureau's ENSO Outlook remains at INACTIVE but conditions and outlooks will be assessed regularly against the criteria needed for elevation to La Niña WATCH.

The Indian Ocean Dipole (IOD) is currently neutral. All six international climate models surveyed suggest negative IOD conditions could develop from the middle of the southern hemisphere winter. However, each of the models show a broad spread of possible scenarios between the neutral IOD and negative IOD levels, with almost no sign of a re-emergence of a positive IOD event. But again, caution must be taken as accuracy of IOD forecasts made at this time of year is low, with forecast accuracy improving from late autumn. A negative IOD typically brings above average winter–spring rainfall to southern Australia.

The Southern Annular Mode (SAM) is currently negative but is forecast to return to neutral levels in the next few days and remain neutral for the coming three weeks. SAM has little influence upon Australian rainfall in autumn.


Image

http://www.bom.gov.au/climate/enso/

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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11456 Postby DorkyMcDorkface » Tue Apr 28, 2020 9:00 am

Shell Mound wrote:
DorkyMcDorkface wrote:The latest Bureau of Meteorology (BOM) ENSO outlook shows the mean straddling the La Niña threshold for ASO (remember that the BOM's criteria for La Niña (El Niño) is lower (higher) than the CPC's). Also note that there are now very few ensemble members that remain in warm-neutral territory by then, and zero members that rise above the El Niño threshold.

Granted, as mentioned preiously, whether or not we get cool-neutral or weak La Niña conditions doesn't really matter as much as the fact that it's increasingly likely we won't be seeing an El Niño by the peak of the Atlantic hurricane season.

http://www.bom.gov.au/climate/ocean/outlooks/archive/20200425//plumes/sstOutlooks.nino34.hr.png

Historically, however, it does seem to matter, at least to a degree. (Note that even 2017 featured La Niña by the peak of the Atlantic hurricane season. If 2020 does not, then its ACE index will likely be substantially lower than that of 2017.) Additionally, if we end up with cool neutral or even plain neutral ENSO—as opposed to weak La Niña—by the peak of the Atlantic hurricane season in ASO, then we may also see a weaker subtropical ridge that results in more storms curving out to sea instead of striking the mainland U.S., given that the -PDO signature—which tends to favour West-Coast troughs and East-Coast ridges—typically tends to be less pronounced in neutral ENSO vs. La Niña. Given current oceanic-atmospheric trends, even weak Niña conditions seem unlikely by the peak of the hurricane season, so not only will the “hyperactive” (as opposed to slightly-above-average) forecasts likely bust on the high side, but the forecasts for steering currents may also prove incorrect.

The prediction is for 19.8 +/- 4.4 total named tropical cyclones, which corresponds to a range between 15 and 24 storms, with a best estimate of 20 named storms. ... If no La Niña develops (by the peak of the Atlantic hurricane season — ed.), then the prediction will be slightly lower: 18.3 +/- 4.3 storms (range of 14-23 storms, with a best guess of 19).

PSU’s 2020 ATL hurricane forecast

Note the significant drop in total NS (from 19.8 to 18.3) simply by having cool neutral ENSO instead of weak La Niña by ASO.


According to the CPC, the ONI for ASO 2017 actually came in at cool-neutral (-0.4). The transition to full-blown La Niña didn't occur until later.

Image

Also, the graphic posted earlier from WeatherTiger does indicates that, on average, seasons that occur during cool-neutral ENSO (and even warm-neutral in some cases) can actually produce more activity than seasons that occur during stronger La Niñas.
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11457 Postby aspen » Tue Apr 28, 2020 11:03 am

DorkyMcDorkface wrote:
Shell Mound wrote:
DorkyMcDorkface wrote:The latest Bureau of Meteorology (BOM) ENSO outlook shows the mean straddling the La Niña threshold for ASO (remember that the BOM's criteria for La Niña (El Niño) is lower (higher) than the CPC's). Also note that there are now very few ensemble members that remain in warm-neutral territory by then, and zero members that rise above the El Niño threshold.

Granted, as mentioned preiously, whether or not we get cool-neutral or weak La Niña conditions doesn't really matter as much as the fact that it's increasingly likely we won't be seeing an El Niño by the peak of the Atlantic hurricane season.

http://www.bom.gov.au/climate/ocean/outlooks/archive/20200425//plumes/sstOutlooks.nino34.hr.png

Historically, however, it does seem to matter, at least to a degree. (Note that even 2017 featured La Niña by the peak of the Atlantic hurricane season. If 2020 does not, then its ACE index will likely be substantially lower than that of 2017.) Additionally, if we end up with cool neutral or even plain neutral ENSO—as opposed to weak La Niña—by the peak of the Atlantic hurricane season in ASO, then we may also see a weaker subtropical ridge that results in more storms curving out to sea instead of striking the mainland U.S., given that the -PDO signature—which tends to favour West-Coast troughs and East-Coast ridges—typically tends to be less pronounced in neutral ENSO vs. La Niña. Given current oceanic-atmospheric trends, even weak Niña conditions seem unlikely by the peak of the hurricane season, so not only will the “hyperactive” (as opposed to slightly-above-average) forecasts likely bust on the high side, but the forecasts for steering currents may also prove incorrect.

The prediction is for 19.8 +/- 4.4 total named tropical cyclones, which corresponds to a range between 15 and 24 storms, with a best estimate of 20 named storms. ... If no La Niña develops (by the peak of the Atlantic hurricane season — ed.), then the prediction will be slightly lower: 18.3 +/- 4.3 storms (range of 14-23 storms, with a best guess of 19).

PSU’s 2020 ATL hurricane forecast

Note the significant drop in total NS (from 19.8 to 18.3) simply by having cool neutral ENSO instead of weak La Niña by ASO.


According to the CPC, the ONI for ASO 2017 actually came in at cool-neutral (-0.4). The transition to full-blown La Niña didn't occur until later.

https://i.ibb.co/G7VtfQS/ASO2017.png

Also, the graphic posted earlier from WeatherTiger does indicates that, on average, seasons that occur during cool-neutral ENSO (and even warm-neutral in some cases) can actually produce more activity than seasons that occur during stronger La Niñas.

The mean ENSO anomaly from the BOM graphic is -0.8 C by ASO, which is comparable to that of 2011 (-0.7 C) and 2016 (-0.6 C). 2011 was a hyperactive year in terms of named storms and had an ACE of 125, while 2016 was more of a “quality > quantity” active season with an ACE of 141. While this would seem to show decreasing ACE with a stronger La Niña, this is a very small sample size and two very different scenarios. 2011 was coming off of a strong La Niña (-1.6 at ASO), while 2016 transitioned to a weak La Niña after an extremely strong El Niño (peak anomaly of +2.6 C). 2020, by comparison, is projected to gradually reach a similar ENSO anomaly by ASO after only a weak El Niño.

I’m not exactly sure what this could mean for activity in 2020 compared to 2011 and 2016, but I thought this was worth pointing out. I’m thinking hurricane and major hurricane totals will be slightly higher than 7/4 in both 2011 and 2016 because of a potentially broiling Gulf and a favorable MDR, but at this point, it’s all up in the air (no pun intended).
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Re: ENSO Updates

#11458 Postby cycloneye » Tue Apr 28, 2020 12:11 pm

As all the models are showing and the comments from some members that there will not be El Niño in 2020 I wanted to add a little more humor by showing this. :D

Image
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Re: ENSO Updates

#11459 Postby OURAGAN » Wed Apr 29, 2020 5:51 am

All el Nino values are going down now
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Re: ENSO Updates: CPC Weekly update= Niño 3.4 down to +0.6C

#11460 Postby Shell Mound » Wed Apr 29, 2020 5:59 am

DorkyMcDorkface wrote:
Shell Mound wrote:
DorkyMcDorkface wrote:The latest Bureau of Meteorology (BOM) ENSO outlook shows the mean straddling the La Niña threshold for ASO (remember that the BOM's criteria for La Niña (El Niño) is lower (higher) than the CPC's). Also note that there are now very few ensemble members that remain in warm-neutral territory by then, and zero members that rise above the El Niño threshold.

Granted, as mentioned preiously, whether or not we get cool-neutral or weak La Niña conditions doesn't really matter as much as the fact that it's increasingly likely we won't be seeing an El Niño by the peak of the Atlantic hurricane season.

http://www.bom.gov.au/climate/ocean/outlooks/archive/20200425//plumes/sstOutlooks.nino34.hr.png

Historically, however, it does seem to matter, at least to a degree. (Note that even 2017 featured La Niña by the peak of the Atlantic hurricane season. If 2020 does not, then its ACE index will likely be substantially lower than that of 2017.) Additionally, if we end up with cool neutral or even plain neutral ENSO—as opposed to weak La Niña—by the peak of the Atlantic hurricane season in ASO, then we may also see a weaker subtropical ridge that results in more storms curving out to sea instead of striking the mainland U.S., given that the -PDO signature—which tends to favour West-Coast troughs and East-Coast ridges—typically tends to be less pronounced in neutral ENSO vs. La Niña. Given current oceanic-atmospheric trends, even weak Niña conditions seem unlikely by the peak of the hurricane season, so not only will the “hyperactive” (as opposed to slightly-above-average) forecasts likely bust on the high side, but the forecasts for steering currents may also prove incorrect.

The prediction is for 19.8 +/- 4.4 total named tropical cyclones, which corresponds to a range between 15 and 24 storms, with a best estimate of 20 named storms. ... If no La Niña develops (by the peak of the Atlantic hurricane season — ed.), then the prediction will be slightly lower: 18.3 +/- 4.3 storms (range of 14-23 storms, with a best guess of 19).

PSU’s 2020 ATL hurricane forecast

Note the significant drop in total NS (from 19.8 to 18.3) simply by having cool neutral ENSO instead of weak La Niña by ASO.


According to the CPC, the ONI for ASO 2017 actually came in at cool-neutral (-0.4). The transition to full-blown La Niña didn't occur until later.

https://i.ibb.co/G7VtfQS/ASO2017.png

Also, the graphic posted earlier from WeatherTiger does indicates that, on average, seasons that occur during cool-neutral ENSO (and even warm-neutral in some cases) can actually produce more activity than seasons that occur during stronger La Niñas.

In my post, I used the MEI instead of ONI-based ENSO values. The MEI can be a more reliable indicator of the overall atmospheric state than the ONI.
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