Enso Status on 5th September 2018

Enso Neutral Conditions Prevails August 2018

How ONI is determined:

The ONI is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO. Defined as the three-month running-mean SST departures in the Niño 3.4 region. Departures are based on a set of further improved homogeneous historical SST analyses (Extended Reconstructed SST – ERSST.v5). Explanation about ERSST.v5 is given here.

The SST reconstruction methodology is described in Huang et al., 2015, J. Climate, vol. 28, 911-930.
CPC uses current Climatology based on 1986-2015 which has been changed late last year from base years 1981-2010. Explanation about Climatology base years change is given here.

NOAA Operational Definitions for El Niño and La Niña, El Niño: characterized by a positive ONI greater than or equal to +0.5ºC. La Niña: characterized by a negative ONI less than or equal to -0.5ºC. By historical standards, to be classified as a full-fledged El Niño or La Niña episode, these thresholds must be exceeded for a period of at least 5 consecutive overlapping 3-month seasons.

CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST departures meet or exceed +/- 0.5ºC along with consistent atmospheric features. These anomalies must also be forecast to persist for 3 consecutive months.

Last five ONI Index are FMA 2018 -0.6ºC, MAM 2018 -0.4ºC, AMJ 2018 -0.1ºC, MJJ 2018 +0.1ºC and JJA 2018 +0.1ºC. Latest Nino 3.4 SST is +0.04ºC and the calculated ONI JJA 2018 is +0.1ºC, though positive but in neutral zone. Hence ENSO neutral conditions continues to exist.

La Nina event 2017-18 had officially ended at the end of April 2018 (FMA 2018). ENSO neutral conditions exists since then.

Latest Oceanic Nino Index Graph Shows ENSO Neutral Conditions Continues JJA 2018 Season

The Table below shows the monthly SST of Nino3.4 Region and the Climate adjusted normal SST and SST anomaly for last two years. Climate Base 1986-2015. ERSST.v5

Period    Nino3.4 ClimAdjust
YR   MON  Temp.ºC Temp.ºC ANOM ºC

2016   8   26.28   26.91   -0.63
2016   9   26.15   26.80   -0.65
2016  10   25.98   26.75   -0.78
2016  11   25.95   26.75   -0.80
2016  12   26.10   26.65   -0.55
2017   1   26.12   26.45   -0.33
2017   2   26.68   26.66    0.02
2017   3   27.33   27.21    0.12
2017   4   28.04   27.73    0.30
2017   5   28.30   27.85    0.45
2017   6   28.06   27.65    0.41
2017   7   27.54   27.26    0.28
2017   8   26.70   26.91   -0.21
2017   9   26.29   26.80   -0.51
2017  10   26.15   26.75   -0.60
2017  11   25.74   26.75   -1.01
2017  12   25.62   26.65   -1.04
2018   1   25.58   26.45   -0.88
2018   2   25.98   26.66   -0.68
2018   3   26.50   27.21   -0.71
2018   4   27.32   27.73   -0.41
2018   5   27.74   27.85   -0.11
2018   6   27.76   27.65    0.13
2018   7   27.42   27.26    0.16
2018   8   26.94   26.91    0.04

Southern Oscillation Index

SOI Monthly graph up to August 2018 as per The Long Paddock – Queensland Government.

Summary by: Climate Prediction Center / NCEP  Dated 6th August 2018

ENSO Alert System Status: El Niño Watch

ENSO-neutral conditions are present.*
Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean.
There is ~60% chance of El Niño in the Northern Hemisphere fall 2018 (September-November), increasing to ~70% during winter 2018-19.

* 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.

As per BOM – Australia 31st July 2018

ENSO outlooks

All earlier updates are listed below:

Click here for Update “ENSO Neutral Conditions Prevail July 2018”

Click here for Update “Full-fledged El Nino Ruled Out During Southwest Monsoon 2018”

Click here for Update “Weak La Nina Exists Till The End Of April 2018”

Click here for Update “Full Fledged La Nina Event Has Developed At The End Of March 2018”