The 2017-18 La Nina Event Expected To Commence At The End Of March – Four Consecutive 3-Monthly Seasons Have ONI Index -0.5ºC Or Below Till February 2018

ENSO Status on 7th March 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.

Enso neutral conditions have prevailed subsequent to the last 2016-17 La Nina event that ended at the end of January 2017 (NDJ 2017).

Last five ONI Index are ASO 2017 -0.4ºC, SON 2017 -0.7ºC, OND 2017 -0.9ºC, NDJ 2018 -1.0ºC and DJF 2018 -0.9ºC. Now four 3-monthly seasonal ONI Index are in the La Nina zone so an official La Nina event is expected at the end of March 2018.

 

Latest Oceanic Nino Index (ONI) Graph Showing Enso Neutral Event Ending February 2018

(Potential La Nina At The End Of March 2018)

 

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   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   25.58   26.45   -0.87
2018   2   25.96   26.66   -0.70

 

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 5th March 2018 is −2.3, which is within the neutral range. While the SOI fluctuates more during the southern hemisphere summer due to movement of tropical systems, it has spent most of 2018 to date within the neutral 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.

Recent (preliminary) Southern Oscillation Index values as per The Long Paddock – Queensland Government.

 

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

 

 

30 Days average SOI was -6.91 at the end of February 2018 and -2.84 on 6th March 2018 as per The Long Paddock – Queensland Government and 90 Days average SOI was -0.35.

 

Summary by: Climate Prediction Center / NCEP  Dated 5th March 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. A transition from La Niña to ENSO-neutral is most likely during the Northern Hemisphere spring (~55% chance of ENSO-neutral during the March-May season).*

 

As per BOM -Australia 27th February 2018

ENSO outlooks

All earlier updates are listed below:

Click here for Update “Three Consecutive 3-Monthly Seasons Have Oni -0.5ºC Or 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”

 

22 Replies to “The 2017-18 La Nina Event Expected To Commence At The End Of March – Four Consecutive 3-Monthly Seasons Have ONI Index -0.5ºC Or Below Till February 2018”

  1. Sir maru anuman che ke chomasu 50%50chanch che te sachu che sir tamaru su hal nu anuman che

  2. Dear ashok Bhai
    Ame to Tamara final comment ni rah Joy ke chomasu saru chhe ke nay
    Baki amne kany khabar pade nay.
    Tamari aagahi uper to ame mal ni kharidi karata hoy chhi
    Ke stock karvo ke mal Khali karvo
    Thanks a lot

  3. Sir what is the basic difference between La-Nino & El-Nino & what is its impact on our monsoon?

  4. Respected sir,
    Can you tell me the current situation of IOD. What is the current statu +ve or -ve. If it is not possible to tell know than which time is perfect for judgment regarding IOD.

    1. It is surprising that you are not aware about the Menu structure of this website !

      Please see Menu. There is a link for IOD and the details about the current conditions

  5. ENSO એટલે શું તે થાય તો વાવણી મોઙી થાય કેશુ ???
    બતાવો શર

  6. Sir 1k Question che k to aapda chomasa mate paku nki kyre tme kyo k La Nina thi saro varsad means aa vakhatnu chomasu saru jse La Nina na lidhe m ane jm pela tme janaivu k La Nina mate 5 trimashik mapdand hova joye ane hal 4 to thai gya che
    To sir kyre finally kyo tme k chomasu saru jai ske gya varsh ni jem aapde???

    1. March aakhar ma La Nina Thai jashe.

      Dar mahine fer far thata hoy.

      EL Nino ke La Nina chomasa maate sharerash 6% farak kare chhe….. bija ghana factor hoy chhe.

  7. Hi Ashok Bhai,

    Kadach jo March aakhar ma purna lanino thay to eno matlab avo k 2018 na chomasa ma lanino hse? k pchi a bhi change thya kre?

    Thank you.

  8. Sir
    Tame last ma kidhu ke la nino thase Pan natural condtion ni shayakta nathi
    Mean ke la nino continue rahe chhe????

  9. સર તો આપણા ચોમાસા માટે સારુ કે ખરાબ?

  10. અલનીનોની શુ પોજીશન છે

  11. Comments only regarding La Nina/ENSO/El Nino. Comments about weather should be posted in last Forecast post and not here.

    આ પોસ્ટ માં ફક્ત La Nina/ENSO/El Nino બાબત કમેન્ટ કરવી. હવામાન ની જનરલ કમેન્ટ આગલી આગાહી આપેલ છે તેમાં કરવી અહીં નહિ.

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