El Nino 2018-19 Episode To Continue Into May 2019

Posted on05/05/201925/06/2023AuthorAshok Patel67 Comments

Enso Status on 5th May 2019

Ashok Patel’s Analysis & Commentary :

Using NOAA Criteria, a full-fledged El Nino event started at the end of March 2019 having fulfilled the five consecutive overlapping 3-monthly seasons with ONI greater than or equal to +0.5ºC. El Nino has continued during April 2019 with the sixth 3-monthly season of FMA 2019 at +0.8ºC. The last two Nino3.4 SST anomaly for March is +0.90ºC and April is +0.72ºC. Even if the Nino3.4 SST anomaly of May is around 0.0ºC, the MAM ONI Index would be greater than or equal to +0.5ºC, and so El Nino is expected to continue during May 2019.

Based on earlier more than 100 years weather Data for Indian Summer Monsoon, The Average Rainfall in an El Nino years is 94% of LPA while in La Nina Years it has been 106 % of LPA. El Nino or La Nina may affect the Monsoon differently for different Regions of India.

અશોક પટેલ નું તારણ અને વિશ્લેષણ :

NOAA માપદંડ મુજબ માર્ચ આખર માં વિધિવત ‘એલ નિનો’ ડિક્લેર થયેલ કારણ કે સળંગ 5 અંશતઃ ઢાંકેલ ત્રી-માસિક સીઝન નું ONI ઈન્ડેક્સ +0.5ºC અથવા વધુ રહેલ છે. એપ્રિલ 2019 માં પણ ‘એલ નિનો’ ચાલુ રહે છે અને મે 2019 માં પણ ચાલુ રહેશે. FMA 2019 નું ONI ઈન્ડેક્સ +0.8°C હતું.છેલ્લા બે મહિના નું Nino3.4 SST ઍનોમલી માર્ચ +0.90ºC અને એપ્રિલ +0.72ºC છે. મે 2019 નું SST +0.0ºC આસ પાસ રહે તો પણ MAM 2019 નું ONI +0.5ºC થી વધુ કે બરોબર રહેશે એટલે ‘એલ નિનો’ મે 2019 માં પણ ચાલુ રહેશે.

આગળ ના 100 વર્ષ થી વધુ ની શરેરાશ પ્રમાણે એલ નિનો વર્ષ માં ભારતીય ચોમાસુ 94% રહેલ છે, જયારે લા નિના વર્ષ માં ચોમાસુ 106% રહેલ છે. ભારતીય ચોમાસા માટે વિવિદ્ધ પરિબળો પૈકી નું એલ નિનો/લા નિના ફક્ત એક પરિબળ છે. ભારત ના અલગ અલગ વિસ્તારો ના ચોમાસા પર એલ નિનો/લા નિના ની અસર એક સરખી નથી થતી.

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.

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.

The Climate Prediction Center (CPC) is a United States Federal Agency that is one of the NECP, which are a part of the NOAA

Current El Nino 2018-19 all ONI Index are SON 2018 +0.7ºC, OND 2018 +0.9ºC, NDJ 2019 +0.8ºC, DJF 2019 +0.8ºC, JFM 2019 +0.8ºC and FMA 2019 +0.8ºC. Last three Nino 3.4 SST anomaly are February +0.83ºC, March +0.90ºC and April is +0.72ºC.

Latest Oceanic Nino Index Graph Shows El Nino 2018-19 Continues In April 2019

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

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
2018   9   27.19   26.80    0.39
2018  10   27.62   26.75    0.86
2018  11   27.61   26.75    0.86
2018  12   27.49   26.65    0.84
2019   1   27.21   26.45    0.76
2019   2   27.49   26.66    0.83
2019   3   28.11   27.21    0.90
2019   4   28.46   27.73    0.72

Southern Oscillation Index

As per BOM, Australia:

The 30-day Southern Oscillation Index (SOI) to 3rd May 2019 was -2.5 and is considered in the neutral zone.

Sustained negative values of the SOI below −7 typically indicate El Niño while sustained positive values above +7 typically indicate La Niña. Values between +7 and −7 generally indicate neutral conditions.

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

30 Days average SOI was -2.43 at the end of April 2019 and was -2.97 on 5th May 2019 as per The Long Paddock – Queensland Government and 90 Days average SOI was -7.38

SOI Monthly graph up to April 2019 as per The Long Paddock – Queensland Government.

Summary by: Climate Prediction Center / NCEP Dated 29th April 2019

ENSO Alert System Status: El Niño Advisory
El Niño is present.*

Equatorial sea surface temperatures (SSTs) are above average across most of the Pacific Ocean. The pattern of anomalous convection and winds are consistent with El Niño. A weak El Niño is likely to continue through the Northern Hemisphere summer 2019 (65% chance) and possibly fall (50-55% chance).

* 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 April 2019

ENSO outlooks

While most climate models forecast El Niño-like warmth to persist throughout the remainder of the austral autumn and early winter, the ocean is then likely to cool heading into spring. This could indicate that if El Niño does develop, it is likely to be short lived and weak. Despite this cooling, four of the eight surveyed climate models forecast El Niño-like warmth in September.

Note that model accuracy when forecasting through the autumn months is lower than at other times of the year, due to the natural cycle of ENSO. Forecast accuracy improves for outlooks issued in June.

(Note: winter/spring is with reference to Southern Hemisphere)