El Nino Update on 17th June 2015
Full fledged EL Nino was confirmed at the end of March 2015 when the five consecutive 3 monthly seasons had ONI index of +0.5 C or higher. It has been a weak El nino till date.
March, April & May 2015 SST anomaly for Nino3.4 region is used to calculate the ONI Index for MAM as +0.7ºC.
As per NOAA Officially El Nino is declared as per conditions laid down and shown in ONI Index graph below:
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.
Classification of El Nino:
Weak El Nino: ONI Index +0.5ºC to 0.9ºC
Moderate El Nino: ONI Index +1.0ºC to 1.4ºC
Strong El nino: +1.5ºC to 1.9ºC
Very Strong El nino: +2.0ºC and above
As per classification a weak El Nino exist till date since the last ONI Index for MAM 2015 was +0.7ºC which is below +1.0ºC. Most International forecasters maintain that this El Nino is expected to become moderate and ultimately a strong El nino. This means that the ONI Index has to rise to above +1.5ºC. However, Southern Oscillation Index has been increasing from a negative zone and the SOI value has increased to above zero and is in the neutral zone recently.
Currently the two parameters are out of Sync with one another. This could be a temporary blip and should be monitored.
Latest Southern Oscillation Index values
Queensland Government – The Long Paddock
Average for last 30 days |
2.29 |
|---|---|
Average for last 90 days |
-5.96 |
Daily contribution to SOI calculation |
-1.69 |
March |
-10.67 |
|---|---|
April |
-3.08 |
May |
-13.11 |
As per BOM, Australia:
The Southern Oscillation Index (SOI) was in the negative zone at the end of May 2015 and during the last two weeks has climbed up to above zero and has a positive value in the neutral zone. The latest 30-day SOI value from BOM-Australian Government for period ending June 15th June 2015 is +1.5 which denotes neutral zone.
BOM – 30 Days Moving SOI
