ENSO: Recent Evolution, Current Status and Predictions

[Pages:32]ENSO: Recent Evolution, Current Status and Predictions

Update prepared by:

Climate Prediction Center / NCEP 11 October 2021

Outline

Summary Recent Evolution and Current Conditions Oceanic Ni?o Index (ONI) Pacific SST Outlook U.S. Seasonal Precipitation and Temperature Outlooks Summary

Starting this week, the weekly sea surface temperature data is based on OISSTv2.1 (Huang et al., 2021). This impacts slides #4-9. The source data is available at this link.

Summary

ENSO Alert System Status: La Ni?a Watch ENSO-neutral conditions are present.* Equatorial sea surface temperatures (SSTs) are below average across the central and east-central Pacific Ocean. A transition from ENSO-neutral to La Ni?a is favored in the next couple of months, with a 70-80% chance of La Ni?a during the Northern Hemisphere winter 2021-22.*

* Note: These statements are updated once a month (2nd Thursday of each month) in association with the ENSO Diagnostics Discussion, which can be found by clicking here.

Recent Evolution of Equatorial Pacific SST Departures (oC)

During September 2020 to March 2021, the core of the strongest negative SST anomalies shifted from the eastern to the central Pacific Ocean.

From March to July 2021, equatorial SSTs gradually returned to average over most of the Pacific Ocean.

In the last week, below-average SSTs continued in the central and eastcentral Pacific Ocean.

Ni?o Region SST Departures (oC) Recent Evolution

The latest weekly SST departures are:

Ni?o 4 Ni?o 3.4

Ni?o 3 Ni?o 1+2

-0.7?C -0.6?C -0.3?C 0.1?C

SST Departures (oC) in the Tropical Pacific During the Last Four Weeks

In the last four weeks, equatorial SSTs were below average across most of the equatorial Pacific Ocean, and were above average in the western and far eastern Pacific Ocean.

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Global SST Departures (oC) During the Last Four Weeks

During the last four weeks, equatorial SSTs were below average across most of the equatorial Pacific Ocean. Equatorial SSTs were above average in the western and far eastern Pacific Ocean, the central Indian Ocean, and the Atlantic Ocean.

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Weekly SST Departures during the Last Four Weeks

During the last 4 weeks, negative SSTs strengthened in the central and east-central Pacific Ocean.

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