ENSO Update

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Bulletin December 2018 - Summary

The ENSO status eased back to an El Niño WATCH alert level on the 22nd of January 2019. Atmospheric indicators such as cloudiness, trade winds and the Southern Oscillation Index all continue to generally remain within the ENSO-neutral range. While most climate models indicate ENSO-neutral conditions for the immediate future, the current ocean warmth and likelihood of ongoing warmer than average conditions mean the risk of El Niño remains. Recent observations and climate model outlooks suggest that the immediate risk of El Niño has passed. However, 50% of the climate models surveyed still indicate an increased likelihood that an El Niño will re-develop mid-2019.

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Bulletin December 2018 - El Nino Oscillation

The 30-day Southern Oscillation Index (SOI) to 20 January 2019 was -0.1, and the 90-Day SOI was +0.3. The lack of clear sustained El Nino signal in the SOI indicates the atmospheric circulation required for El Nino has been missing this summer. The coupling of atmospheric circulation and ocean temperature patterns is the mechanism which reinforces and sustains El Nino, and facilitates widespread shifts in Vanuatu weather and climate.

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Bulletin December 2018 - MJO

The MJO is a pulse of atmospheric wave that enhances rainfall in over the Indian and Pacific ocean. MJO is currently inactive over Vanuatu.

Forecasts have the MJO remaining weak for a short time before re-strengthening over the Maritime Continent (which includes Vanuatu) during the upcoming weeks.

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Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

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Bulletin December 2018 - Cloud

Cloud activities were mostly above average throughout Vanuatu (purple color). Thus, bringing normal to above normal rainfall to most islands in Vanuatu in the past month.

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Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

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Bulletin December 2018 - Rainfall

Average rainfall detected by satellite for the last 30 days since January 6th showed normal to above normal rainfall experienced throughout Vanuatu.

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Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

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Bulletin December 2018 - SST

Sea Surface Temperatures between November and December shows slight cooling across the tropical Pacific.

Sub-sea surface temperatures have weakened in the eastern Pacific, and appear to be strengthening in the central Pacific, which is not a typical El Nino pattern.

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Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

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Bulletin December 2018 - MSLP

In the past month, Mean Sea Level Pressure (MSLP) anomalies are indicating normal throughout Vanuatu.

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Note: Due to frequent images update from source provider, the quoted Sources might not give the same images as shown

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Bulletin December 2018 - Model Outlooks

The Climate Model maintains El Nino threshold for the ocean, but atmosphere yet to respond. Model outlooks suggest El Nino levels will be maintained through to May 2019, however model accuracy forecasting through the autumn months is low.

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Bulletin December 2018 - SPCZ

The South Pacific Convergence Zone (SPCZ) shifted southwest from Vanuatu to SE French Polynesia in the past month.

The SPCZ was much stronger than normal and it was displaced to the southwest, thus had some influence on the rainfall over Vanuatu in the past month.

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