ENSO Updates

[cycloneye]

Euro may be showing its natural warm bias again but the MEAN looks realistic IMO. The mean favors a warm up to neutral levels and then dipping back negative entering JJA.
https://i.postimg.cc/bwqcFbRK/ezgif-7-b8432b1ccfbe.gif

If this scenario occurs, then an active North Atlantic 2021 season will happen but I dont think it will reach 30 TC's, however it may be hyperactive with 18-20.

[NotSparta]

Euro may be showing its natural warm bias again but the MEAN looks realistic IMO. The mean favors a warm up to neutral levels and then dipping back negative entering JJA.
https://i.postimg.cc/bwqcFbRK/ezgif-7-b8432b1ccfbe.gif

In this scenario of a slowly warming ENSO that peaks at neutral by April-June before starting to cool again, would the atmosphere switch out of a La Niña state, or will a La Niña state (or a similar state) continue without interruption as the ENSO cools off again?

The current SSTA pattern supports a return to neutral, you probably wouldn't need to change the pattern radically to make it neutral during summer. Perhaps a weakening in the atmospheric footprint but I think a slight Niña signal will remain there

[Kingarabian]

Euro may be showing its natural warm bias again but the MEAN looks realistic IMO. The mean favors a warm up to neutral levels and then dipping back negative entering JJA.
https://i.postimg.cc/bwqcFbRK/ezgif-7-b8432b1ccfbe.gif

If this scenario occurs, then an active North Atlantic 2021 season will happen but I dont think it will reach 30 TC's, however it may be hyperactive with 18-20.

You can definitely still have a hyper active North Atlantic hurricane season with a weak La Nina in place. See 2005 for the Atlantic that barely had a weak La Nina in place for ASO, and also see 2018 for the EPAC hurricane season which had a very weak El Nino in place but ended up hyperactive.

[cycloneye]

The cool pool at the subsurface looks to be expanding. Let's see how things evolve in the next few weeks and months.

[Category5Kaiju]

Euro may be showing its natural warm bias again but the MEAN looks realistic IMO. The mean favors a warm up to neutral levels and then dipping back negative entering JJA.
https://i.postimg.cc/bwqcFbRK/ezgif-7-b8432b1ccfbe.gif

If this scenario occurs, then an active North Atlantic 2021 season will happen but I dont think it will reach 30 TC's, however it may be hyperactive with 18-20.

You can definitely still have a hyper active North Atlantic hurricane season with a weak La Nina in place. See 2005 for the Atlantic that barely had a weak La Nina in place for ASO, and also see 2018 for the EPAC hurricane season which had a very weak El Nino in place but ended up hyperactive.

Heck, you can have a hyperactive Atlantic when there is an El Nino in place too! While most El Ninos hinder the overall activity and strength in the Atlantic, 1969 and 2004 are perfect examples that not all El Ninos are the same

[cycloneye]

60% of Neutral by April to June and a slight La Niña uptick by ASO and SON.

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP/NWS
and the International Research Institute for Climate and Society
11 February 2021

ENSO Alert System Status: La Niña Advisory


Synopsis: There is a ~60% chance of a transition from La Niña to ENSO-Neutral during the Northern Hemisphere spring 2021 (April-June).

La Niña persisted in January, reflected by below-average sea surface temperatures (SST) anomalies extending from the western to east-central Pacific Ocean [Fig. 1]. SSTs returned to near average in the eastern Pacific Ocean by the end of the month, as indicated by the latest weekly Niño-3 and Niño-1+2 index values of -0.3°C and -0.2°C, respectively [Fig. 2]. However, the latest weekly Niño index values in the central (Niño-4) and east-central (Niño-3.4) Pacific Ocean were -1.1°C and -0.7°C. The below-average SSTs were supported by negative subsurface temperature anomalies [Fig. 3], which extended from the surface to at least ~150m below the surface between 160°E and 130°W [Fig. 4]. Low-level wind anomalies remained easterly from the western to east-central (~140°W) tropical Pacific, with the largest amplitude near the Date Line. Upper-level wind anomalies were westerly across most of the tropical Pacific. Tropical convection continued to be suppressed over the western and central Pacific and enhanced around the Philippines and Indonesia [Fig. 5], while both the Southern Oscillation and Equatorial Southern Oscillation remained positive. Overall, the coupled ocean-atmosphere system remains consistent with La Niña.

Most of the models in the IRI/CPC plume predict a transition to ENSO-neutral during the Northern Hemisphere spring 2021 [Fig. 6]. The forecaster consensus is in agreement with this transition and then predicts a continuation of ENSO-neutral at least through the Northern Hemisphere summer. In part, due to the inherent uncertainty in predictions made at this time of year, the forecast for the fall remains split (~50%) between La Niña and the combination of the other two possibilities (El Niño and Neutral). In summary, there is a ~60% chance of a transition from La Niña to ENSO-Neutral during the Northern Hemisphere spring 2021 (April-June; click CPC/IRI consensus forecast for the chances in each 3-month period).

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

[Kingarabian]

850mb wind forecasts continue to show stronger than average trades near the dateline and weaker than average trades in the EPAC. ENSO still looks on track to follow 2012/2017.