El Nino Status on 6th March 2015
Most of the agencies monitoring El Nino have been forecasting every month from the beginning of 2014 that an El Nino would begin in the next two months. The year 2014 has completed without a full fledged El Nino. Only two consecutive overlapping 3-month seasons SON and OND have had ONI index equal to or above +0.5ºC thresh hold till end of 2014. SON 2014= +0.5ºC and OND 2014 = +0.7ºC
At the end of January 2015 we had one more overlapping 3-month season NDJ with ONI index equal to or above +0.5ºC thresh hold. NDJ 2015 ONI=0.7ºC. The recent 3- month season the ONI index for DJF =0.6ºC. This makes total of four consecutive overlapping 3-month seasons SON 2014, OND 2014, NDJ 2015 & DJF 2015 with ONI index equal to or above +0.5ºC thresh hold till end of February 2015. SON 2014= +0.5ºC and OND 2014 = +0.7ºC, NDJ 2015 ONI=0.7ºC and DJF 2015 ONI=0.6ºC.
CPC has issued an El Nino Advisory on 5th March 2015.
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 forecasted to persist for 3 consecutive months.
The atmospheric features does not justify the declaration of El nino because SOI was +0.8 as per BOM.
The fact is that as per NOAA Officially El Nino is declared as per conditions laid down 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.
Southern Oscillation Index
The Southern Oscillation Index (SOI) has moved to neutral zone from negative zone during the last week of February 2015. The latest 30-day SOI value from BOM-Australian Government for period ending 1st March is +0.8 which denotes neutral zone.
SOI Monthly graph till March 2015 – The Long Paddock – Queensland Government