ENSO Status on 5th February 2018
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 were based on a set of improved homogeneous historical SST analyses (Extended Reconstructed SST – ERSST.v4) and have now been updated to 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.
Short lived La Nina ended with last 3-monthly season as NDJ 2017. Subsequently, Enso neutral conditions have prevailed thereafter.
Last five ONI Index are JAS 2017 -0.1ºC, ASO 2017 -0.4ºC, SON 2017 -0.7ºC, OND 2017 -0.9ºC and NDJ 2018 -1.0ºC. Now three 3-monthly seasonal ONI Index are in the La Nina zone and hence the Nino 3.4 Region of Pacific Ocean yet continues to remain officially in ENSO Neutral zone, though leaning towards potential La Nina.
Latest Oceanic Nino Index (ONI) Graph Showing Enso Neutral Event Ending January 2018
(Leaning Towards Potential La Nina)
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 1 29.11 26.45 2.66 2016 2 29.00 26.66 2.34 2016 3 28.90 27.21 1.70 2016 4 28.73 27.73 0.99 2016 5 28.24 27.85 0.39 2016 6 27.70 27.65 0.05 2016 7 26.82 27.26 -0.44 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 25.55 26.45 -0.90
CPC considers El Niño or La Niña conditions to occur when the monthly Niño3.4 OISST departures meet or exceed +/- 0.5°C along with consistent atmospheric features. These anomalies must also be forecast to persist for 3 consecutive months.
Southern Oscillation Index
As per BOM, Australia:
The 30-day Southern Oscillation Index (SOI) to 28 January is +9.2 (90-day value +6.0). The 30-day SOI on 2nd February was +6.9 and has returned to positive zone after a brief fall into the negative range.
Sustained positive values of the SOI above +7 typically indicate La Niña while sustained negative values below −7 typically indicate El Niño. Values between about +7 and −7 generally indicate neutral conditions.
SOI Monthly graph up to January 2018 as per The Long Paddock – Queensland Government.
30 Days average SOI was +8.93 at the end of January 2018 and +6.38 on 3rd February 2018 as per The Long Paddock – Queensland Government and has reentered the positive zone again after brief time in the negative zone.
Summary by: Climate Prediction Center / NCEP Dated 29th January 2018
ENSO Alert System Status: La Niña Advisory
La Niña conditions are present.*
Equatorial sea surface temperatures (SSTs) are below average across the Central and Eastern Pacific Ocean.
La Niña is likely (~85-95%) through Northern Hemisphere winter, with a transition to ENSO-neutral expected during the spring.*
* 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 30th January 2018
International climate models surveyed by the Bureau indicate that the equatorial Pacific sea surface is likely to warm in the coming months, returning to neutral values between late in the austral summer and mid-autumn. Only one out of the eight models maintains La Niña levels into winter (June), while three models are in the neutral range by February. The Bureau’s model POAMA indicates a return to neutral values in April, though remains close to La Niña levels until the end of winter.
In order to consider 2017–18 a La Niña year, NINO3 or NINO3.4 values cooler than −0.8 °C need to be observed for at least three months.
Ashok Patel’s Final Note:
Using NOAA Criteria A Full Fledged La Nina Only Possible by End Of March 2018 .
The current SST January 2018 of Nino 3.4 region is at -0.9°C and so now last three ONI Index have La Nina thresh hold as SON 2017 at -0.7°C, OND 2017 at -0.9°C and NDJ 2018 at -1.0°C and so yet Enso Neutral zone prevails though leaning towards a potential La Nina. The next two consecutive 3-monthly seasons namely DJF 2018 and JFM 2018 should manage to remain equal to or below -0.5°C, for a Full fledged La Nina to be qualified as per NOAA criteria which translates to earliest La Nina at the end of March 2018.
અશોક પટેલ ની નોંધ :
હાલ ENSO ન્યુટ્ર્લ કન્ડિશન છે – NOAA માપદંડ મુજબ વિધિવત La Nina ફક્ત 2018 માર્ચ આખર સુધી મા શક્ય.
ઓસ્ટ્રેલિયા ની BOM સંસ્થા મુજબ હાલ La Nina પરિસ્થિતિ છે. જયારે NOAA મુજબ La Nina એડવાયઝરી છે. હાલ ના અંદાજ મુજબ ENSO ન્યુટ્રલ પરિસ્થિતિ છે અને વિધિવત La Nina ની સ્થિતિ માર્ચ 2018 આખર પહેલા શક્ય નથી (NOAA, U.S. ના માપ દંડ મુજબ ); કારણ કે વિધિવત La Nina ડિક્લેર કરવા માટે ના સળંગ 5 ત્રિમાસિક સીઝન La Nina માપ દંડ પ્રમાણે હોવા જોઈએ જે પૈકી હાલ 3 ત્રિમાસિક સીઝન La Nina માપદંડ પ્રમાણે છે. માટે ઓછા માં ઓછા હજુ 2 ત્રિમાસિક સીઝન માં ONI ઈન્ડેક્સ -0.5°C અથવા નીચે રહેવું જોઈએ.
All earlier updates are listed below:
Click here for Update “ENSO Neutral Conditions Prevails”
Click here for Update “ENSO Neutral Conditions Prevails With JAS 2017 ONI Index At -0.2ºC”
Click here for Update “Theoretically El Nino Not Possible During 2017”
Click here for Update “Theoretically El Nino Not Possible During The Indian Southwest Monsoon 2017”
Click here for Update “Full Fledged El Nino Not Possible During The Indian Southwest Monsoon 2017”
Click here for Update “ENSO Neutral Conditions At End Of February 2017”
Click here for Update “2016/17 Qualifies As A La Nina Event”
Click here for Update “Enso Neutral Conditions At End Of October 2016”
Click here for Update “Full Fledged La Nina Not Possible During 2016”
Click here for Update “Demise Of El Nino Brings ENSO Neutral Conditions At End Of July 2016”
Click here for Update “Moderate El Nino Persists Till End Of May 2016”
Click here for Update “Strong El Nino Persists Till April 2016”
Click here for Update “NOAA ERSST.v4 & ERSST.v3b & Effects On ENSO Events”
Click here for Update “Yet A Weak El Nino – 6th June 2105”
Click here for Update “El Nino Update – 5th May 2015”
Click here for Update “Weak El Nino Develops March 2015”
Click here for Update “El Nino Status – 6th March 2015”
Click here for Update “El Nino Status – 7th February 2015”
Click here for Update “El Nino Status – 6th January 2015”
Click here for Update “El Nino Status 6th November 2014”