ENSO Updates (2007 thru 2023)

[Ptarmigan]

Here is the subsurface cross of April 1973. Courtesy of ecmwf ocean reanalysis

1973-1974 is one of the strongest La Nina. There were strong ones in 1915-1918, 1955-1956, 1956-1957, 1988-1989, and 2010-2011.

[Kingarabian]

This drought in Hawaii caused by this El-Nino has been brutal lately.

[cycloneye]

10 days after the CFSv2 fix,it has slowly gone in tune with the other models and now it forecasts Moderate La Nina around the August,September and October period.

[Ntxw]

Down to 1.3C this week. If we went the rapid fall (0.2-0.3C drops per week) we would fall below 0.5C by the end of May. If it was stair stepped it would probably be June.

One thing the potential Nina is lacking at the surface thus far is significant above normal trades.

[cycloneye]

Found this nitid loop from 1970 to 2001 of the subsurface anomalies.

[cycloneye]

Text of the CPC update of 4/11/16 that has Nino 3.4 down to +1.3C.

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

[TeamPlayersBlue]

That loop was fascinating. Great find!

[Dean_175]

Down to 1.3C this week. If we went the rapid fall (0.2-0.3C drops per week) we would fall below 0.5C by the end of May. If it was stair stepped it would probably be June.

One thing the potential Nina is lacking at the surface thus far is significant above normal trades.

Why would we expect trades to be significantly above average while still in El Nino?

[cycloneye]

La Nina watch has been issued by the Aussies.

El Niño declining; 50 per cent likelihood of La Niña for later in 2016



While the 2015–16 El Niño remains at weak to moderate levels, recent changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks, suggest the likelihood of La Niña forming in 2016 has increased to around 50%. As a result, the Bureau's ENSO Outlook status has moved to La Niña WATCH.

Temperatures below the Pacific Ocean surface have declined since late 2015, with all but the top 50 metres now cooler than normal. At the sea surface, temperatures have cooled by over 1 °C since their peak, but remain warmer than average and still at El Niño levels. The Southern Oscillation Index and trade winds also show clear signs that El Niño is in decline. The SOI has recently risen to near-neutral levels, while trade winds are near normal. However some indicators, such as cloudiness near the Date Line, have shown only a limited shift away from El Niño patterns.

International climate models suggest El Niño will continue to weaken during the southern autumn, returning to neutral levels by mid-2016. By spring, five of the eight surveyed models suggest La Niña is likely, with three remaining neutral. ENSO forecasts made at this time of year tend to have lower accuracy than at other times, with a clearer picture to emerge over the coming months.


The ENSO Outlook is now at La Niña WATCH. While the current El Niño is expected to persist until late autumn or early winter, there are early signs that the chance of a La Niña developing by spring 2016 has increased.

The La Niña WATCH criteria have been met following expert assessment of the steady cooling in the surface and sub-surface of the tropical Pacific Ocean and updated model outlooks indicating increased likelihood of cooling to La Niña thresholds by spring 2016.

A La Niña WATCH means that there is approximately a 50% chance of a La Niña developing in 2016, which is about twice the normal likelihood.


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

[cycloneye]

March PDO was up to +2.40.It was at +1.75 in Febuary. El Nino trying to resist from going away?

http://research.jisao.washington.edu/pdo/PDO.latest

[Ntxw]

Down to 1.3C this week. If we went the rapid fall (0.2-0.3C drops per week) we would fall below 0.5C by the end of May. If it was stair stepped it would probably be June.

One thing the potential Nina is lacking at the surface thus far is significant above normal trades.

Why would we expect trades to be significantly above average while still in El Nino?

Should there not be at least some spurts of stronger trades? I wouldn't expect a reversal until La Nina is established though.

[Kingarabian]

Down to 1.3C this week. If we went the rapid fall (0.2-0.3C drops per week) we would fall below 0.5C by the end of May. If it was stair stepped it would probably be June.

One thing the potential Nina is lacking at the surface thus far is significant above normal trades.

Why would we expect trades to be significantly above average while still in El Nino?

Should there not be at least some spurts of stronger trades? I wouldn't expect a reversal until La Nina is established though.

Are La Nina transitions not the same as El Nino transitions? Because you're right. The precursor to this super Nino were patches of strong WWB. Because we all saw what happened 2 years ago... very warm pool surfaced but with no winds kept El Nino at bay.

Also the SOI is tanking again. Looks like the atmosphere is not on the same page.

[NDG]

Why would we expect trades to be significantly above average while still in El Nino?

Should there not be at least some spurts of stronger trades? I wouldn't expect a reversal until La Nina is established though.

Are La Nina transitions not the same as El Nino transitions? Because you're right. The precursor to this super Nino were patches of strong WWB. Because we all saw what happened 2 years ago... very warm pool surfaced but with no winds kept El Nino at bay.

Also the SOI is tanking again. Looks like the atmosphere is not on the same page.

Similar to '98 about this same time, when the SOI did not go to a positive regime until June of that year, something to keep in mind.

[Yellow Evan]

Levi Cowan ‏@TropicalTidbits 3h3 hours ago

Substantial cooling beginning in eastern equatorial Pacific. This did not happen following 1983 and 1998 El Ninos.

Not too surprising given that the El Nino has been more center-based that normal. We could be in store for an extended La Nina with interesting consequences.

[Hurricaneman]

Levi Cowan ‏@TropicalTidbits 3h3 hours ago

Substantial cooling beginning in eastern equatorial Pacific. This did not happen following 1983 and 1998 El Ninos.

Not too surprising given that the El Nino has been more center-based that normal. We could be in store for an extended La Nina with interesting consequences.

Maybe even a nasty Atlantic hurricane season possibly

[Dean_175]

Why would we expect trades to be significantly above average while still in El Nino?

Should there not be at least some spurts of stronger trades? I wouldn't expect a reversal until La Nina is established though.

Are La Nina transitions not the same as El Nino transitions? Because you're right. The precursor to this super Nino were patches of strong WWB. Because we all saw what happened 2 years ago... very warm pool surfaced but with no winds kept El Nino at bay.

Also the SOI is tanking again. Looks like the atmosphere is not on the same page.

Well yes, there can be some spurts of stronger easterlies- but the most important thing for now is that the easterlies be at least near-normal. The El Nino is weakening, but there won't be La Nina atmospheric patterns until there are some cool anomalies at the surface. We will still eventually need to get stronger than normal trades if a La Nina is to actually develop though. In 2014, the surface actually did warm to near El Nino levels- but there were never any westerly anomalies, and so we ended up warm neutral. I guess that if we never had any stronger than normal easterlies at all this year, we could end up just reaching cool neutral.

The thermocline is becoming shallower across the equatorial Pacific, and the subsurface temperatures are up to a few degrees below normal. Even normal trades will produce stronger upwelling of cooler water than normal.

[Kingarabian]

Should there not be at least some spurts of stronger trades? I wouldn't expect a reversal until La Nina is established though.

Are La Nina transitions not the same as El Nino transitions? Because you're right. The precursor to this super Nino were patches of strong WWB. Because we all saw what happened 2 years ago... very warm pool surfaced but with no winds kept El Nino at bay.

Also the SOI is tanking again. Looks like the atmosphere is not on the same page.

Similar to '98 about this same time, when the SOI did not go to a positive regime until June of that year, something to keep in mind.

Well yes, there can be some spurts of stronger easterlies- but the most important thing for now is that the easterlies be at least near-normal. The El Nino is weakening, but there won't be La Nina atmospheric patterns until there are some cool anomalies at the surface. We will still eventually need to get stronger than normal trades if a La Nina is to actually develop though. In 2014, the surface actually did warm to near El Nino levels- but there were never any westerly anomalies, and so we ended up warm neutral. I guess that if we never had any stronger than normal easterlies at all this year, we could end up just reaching cool neutral.

The thermocline is becoming shallower across the equatorial Pacific, and the subsurface temperatures are up to a few degrees below normal. Even normal trades will produce stronger upwelling of cooler water than normal.

Good points. But the PDO is still very warm. I wonder how that will affect things. The Super Nino of 97-98 had very warm PDO values until April before switching negative. So we'll see what happens this time.

[Ntxw]

I think the La Nina will come. It's just if there is going to be a stronger one vs a weak Nina we'd need to see some more impressive trades to kick up. The longer it takes the more difficult it could be.

[cycloneye]

ENSO Alert System Status: El Niño Advisory/La Niña Watch



Synopsis: A transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with an increasing chance of La Niña during the second half of the year.

Sea surface temperature (SST) anomalies were between 1.0° and 1.5°C across most of the central and eastern equatorial Pacific Ocean during early April (Fig. 1), having weakened appreciably over the last month. The latest weekly values for all of the Niño indices dropped to below 1.5°C (Fig. 2). The subsurface temperature anomaly in the central and eastern Pacific decreased to negative values (Fig. 3) in association with a significant expansion of below-average temperatures at depth (Fig. 4). Low-level westerly wind anomalies and upper-level easterly wind anomalies weakened compared to February. The equatorial Southern Oscillation Index (SOI) remained negative but weakened, while the traditional SOI was near zero. Enhanced convection continued over the central tropical Pacific but weakened east of the Date Line, and was suppressed over northern Indonesia and the Philippines (Fig. 5). Collectively, these anomalies reflect a weakening El Niño.

Nearly all models predict further weakening of El Niño, with a transition to ENSO-neutral likely during late spring or early summer 2016 (Fig. 6). Then, the chance of La Niña increases during the late summer or early fall. The official forecast is consistent with the model forecasts, also supported by a historical tendency for La Niña to follow strong El Niño events. A transition to ENSO-neutral is likely during late Northern Hemisphere spring or early summer 2016, with an increasing chance of La Niña during the second half of the year (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).

[NDG]

Going down down down. Things from this point on ain't no repeat of '83. By this time in '83 Nino 1+2 is nearing +3 deg C on its way up to a whopping +4.62 deg C in June.