ENSO Status on 6th April 2017
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 improved homogeneous historical SST analyses (Extended Reconstructed SST – ERSST.v4). 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.
Full fledged La Nina event had been confirmed at the end of January 2017 relying on the official NOAA definition for La Nina, because there were five 3-monthly seasons JAS 2016 at -0.6ºC, ASO 2016 at -0.7ºC, SON 2016 at -0.8ºC, OND 2016 at -0.8ºC, NDJ 2017 at -0.7ºC having La Nina threshold.
ONI Index for DJF 2017 was -0.4ºC which was marginally lower than the La Nina thresh hold and hence the Nino 3.4 Region of Pacific Ocean had entered ENSO Neutral zone.
ONI Index for JFM 2017 is -0.2ºC which indicates the Nino 3.4 Region of Pacific Ocean had remained in the ENSO Neutral zone.
Latest Oceanic Nino Index (ONI) Graph Showing Enso Neutral Event For Last Two Months Till End Of March 2017
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.
Period Nino3.4 ClimAdjust YR MON Temp.ºC Temp.ºC ANOM ºC 2015 3 27.79 27.32 0.47 2015 4 28.59 27.86 0.73 2015 5 28.83 27.98 0.85 2015 6 28.70 27.76 0.94 2015 7 28.50 27.37 1.13 2015 8 28.47 27.02 1.45 2015 9 28.62 26.94 1.68 2015 10 28.86 26.91 1.95 2015 11 29.14 26.88 2.25 2015 12 29.04 26.80 2.24 2016 1 28.95 26.61 2.33 2016 2 28.89 26.80 2.09 2016 3 28.86 27.32 1.54 2016 4 28.96 27.86 1.10 2016 5 28.59 27.98 0.60 2016 6 27.81 27.76 0.05 2016 7 26.98 27.37 -0.39 2016 8 26.39 27.02 -0.63 2016 9 26.20 26.94 -0.74 2016 10 26.04 26.91 -0.87 2016 11 25.96 26.88 -0.93 2016 12 26.08 26.80 -0.72 2017 1 26.24 26.61 -0.37 2017 2 26.63 26.80 -0.17 2017 3 27.30 27.32 -0.02
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 26 March is +5.6 (90-day value +2.1). SOI values have generally been within the neutral range since mid-October.
The latest 30-day Southern Oscillation Index (SOI) on 3rd April 2017 is 3.4 within the neutral ENSO 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 March 2017 as per The Long Paddock – Queensland Government.
SOI was 3.8 at the end of March 2017 and 0.59 on 5th March 2017 as per The Long Paddock – Queensland Government.
Summary by: Climate Prediction Center / NCEP Dated 3rd April 2017
ENSO Alert System Status: Not Active
ENSO-neutral conditions are present.* Equatorial sea surface temperatures (SSTs) are near-average across the central and east-central Pacific. They are above-average in the eastern Pacific Ocean. ENSO-neutral conditions are favored to continue through at least the Northern Hemisphere spring 2017, with increasing chances for El Niño development into the fall.*
* 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 28th March 2017
El Niño WATCH Remains:
The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Bureau’s ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017.
Ashok Patel’s Final Note: Full Fledged El Nino Not Possible During The Indian Southwest Monsoon 2017 Using NOAA Criteria.
Although an El Nino Watch remains as per BOM, the current SST of Nino 3.4 region is below normal at -0.02°C and also the last ONI Index available is JFM 2017 at -0.2°C which is yet in the Enso Neutral zone. The SST for April is not expected to reach 1.5 C and hence the ONI Index for FMA 2017 will be < 0.5°C . Hence earliest 3-monthly season which can hypothetically reach 0.5°C would be MAM 2017. If and only if the NINO 3.4 region heats up continuously for the next Four 3-monthly seasons namely AMJ 2017, MJJ 2017, JJA 2017 & JAS 2017 and if all the ONI indexes manages to remain equal to or above 0.5°C, then it will qualify for a Full fledged El Nino as per NOAA criteria. However, by that time the Southwest Monsoon 2017 would have already ended.
અશોક પટેલ ની નોંધ :
ઓસ્ટ્રેલિયા ની BOM સંસ્થા મુજબ 2017 માં એલ નિનો થવા ની 50% શક્યતા ના એંધાણ આપવામાં આવ્યા હોવા છતાં મારુ માનવું છે કે આગામી ચોમાસા દરમિયાન વિધિવત એલ નિનો (NOAA, U.S. ના માપ દંડ મુજબ ) શક્ય નથી. વિધિવત એલ નિનો જો ડિક્લેર થાય તો પણ ભારત નું દક્ષિણ પશ્ચિમ ચોમાસુ ત્યારે પૂરું થઇ ગયું હશે.
El Nino Update In Akila Daily Dated 6th April 2017
El Nino Update In Sanj Samachar Daily Dated 6th April 2017