ENSO Status on 15th October 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 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.
Short lived La Nina ended with last 3-monthly season as NDJ 2017. Subsequently, Enso neutral conditions have prevailed thereafter.
Last five ONI Index are MAM 2017 +0.3ºC, AMJ 2017 +0.4ºC, MJJ 2017 +0.4ºC, JJA 2017 +0.1ºC and JAS 2017 -0.2ºC (CPC/NOAA has it at -0.1°C ) hence the Nino 3.4 Region of Pacific Ocean continues to remain in ENSO Neutral zone.
Latest Oceanic Nino Index (ONI) Graph Showing Enso Neutral Event For Last Three 3- Monthly Seasons Ending September 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. ERSST.v5
Period Nino3.4 ClimAdjust YR MON Temp.ºC Temp.ºC ANOM ºC 2015 10 29.07 26.75 2.32 2015 11 29.41 26.75 2.67 2015 12 29.26 26.65 2.60 2016 1 29.11 26.45 2.66 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 26.67 26.66 0.01 2017 3 27.31 27.21 0.11 2017 4 28.03 27.73 0.29 2017 5 28.29 27.85 0.44 2017 6 28.05 27.65 0.39 2017 7 27.53 27.26 0.27 2017 8 26.69 26.91 -0.22 2017 9 26.30 26.80 -0.50
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 8th October is +9.1 (90-day value +6.6), having passed into the La Niña value range within the last week.
The latest 30-day Southern Oscillation Index (SOI) on 14th October 2017 is +8.5 which is in the La Nina zone.
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 September 2017 as per The Long Paddock – Queensland Government.
30 Days average SOI was +6.16 at the end of September 2017 and +9.79 on 14th October 2017 as per The Long Paddock – Queensland Government.
Summary by: Climate Prediction Center / NCEP Dated 9th October 2017
ENSO Alert System Status: La Niña Watch
ENSO-Neutral conditions are present.*
Equatorial sea surface temperatures (SSTs) are near-to-below average across the central and eastern Pacific Ocean.
There is an increasing chance(~55%-60%) of La Niña during the Northern Hemisphere fall and winter 2017-18.*
* 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
EL NIÑO/SOUTHERN OSCILLATION (ENSO) DIAGNOSTIC DISCUSSION issued by CLIMATE PREDICTION CENTER/NCEP/NWS and the International Research Institute for Climate and Society
12 October 2017
ENSO Alert System Status: La Niña Watch
Synopsis: La Niña conditions are favored (~55-65%) during the Northern Hemisphere fall and
winter 2017-18.
As per BOM -Australia 10th October 2017
Weaker trade winds stall cooling in tropical Pacific – ENSO Outlook Inactive:
International climate models surveyed by the Bureau indicate that further cooling of equatorial Pacific Ocean sea surface temperatures is expected during Northern Hemisphere Autumn and into Northern Hemisphere Winter. All models anticipate that SSTs may approach or surpass La Niña thresholds during Northern Hemisphere Autumn or early Northern Hemisphere Winter. However, only three models indicate that these SSTs will persist long enough to be classified as a La Niña event.
Ashok Patel’s Final Note: Full Fledged La Nina Possible Earliest End Of February 2018 Using NOAA Criteria.
The current SST of Nino 3.4 region is at -0.5°C at and the last ONI Index available is JAS 2017 at -0.2°C (CPC/NOAA has it at -0.1°C ) and is yet in the Enso Neutral zone. There is not a single 3-monthly seasonal period having ONI Index of -0.5°C or lower. Hence, next Five 3-monthly seasons namely ASO 2017, SON 2017, OND 2017, NDJ 2018 & DJF 2018 should manage to remain equal to or below -0.5°C, for a Full fledged La Nina to be qualified as per NOAA criteria which translates to earliest at the end of February 2018.
અશોક પટેલ ની નોંધ :
ઓસ્ટ્રેલિયા ની BOM સંસ્થા મુજબ હાલ ENSO ન્યુટ્રલ પરિસ્થિતિ છે. જયારે NOAA મુજબ લા નિના વૉચ ની સ્થિતિ છે. હાલ ના અંદાજ મુજબ 2017 નું વર્ષ ENSO ન્યુટ્રલ માં પસાર થશે. વિધિવત લા નિના ની સ્થિતિ ફેબ્રુઆરી 2018 આખર પહેલા શક્ય નથી (NOAA, U.S. ના માપ દંડ મુજબ ) કારણ કે વિધિવત લા નિના ડિક્લેર કરવા માટે ના સળંગ 5 ત્રિમાસિક સીઝન લા નિના માપ દંડ પ્રમાણે હોવા માટે ઓછા માં ઓછા 5 મહિના લાગશે.
All earlier updates are listed below:
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”
Click here for Update “Full Fledged El Nino Not Possible During The Indian Southwest Monsoon 2017”
Click here for Update “ENSO Neutral Conditions At End Of February 2017”
Click here for Update “2016/17 Qualifies As A La Nina Event”
Click here for Update “Enso Neutral Conditions At End Of October 2016”
Click here for Update “Full Fledged La Nina Not Possible During 2016”
Click here for Update “Demise Of El Nino Brings ENSO Neutral Conditions At End Of July 2016”
Click here for Update “Moderate El Nino Persists Till End Of May 2016”
Click here for Update “Strong El Nino Persists Till April 2016”
Click here for Update “NOAA ERSST.v4 & ERSST.v3b & Effects On ENSO Events”
Click here for Update “Yet A Weak El Nino – 6th June 2105”
Click here for Update “El Nino Update – 5th May 2015”
Click here for Update “Weak El Nino Develops March 2015”
Click here for Update “El Nino Status – 6th March 2015”
Click here for Update “El Nino Status – 7th February 2015”
Click here for Update “El Nino Status – 6th January 2015”
Click here for Update “El Nino Status 6th November 2014”
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