ENSO Update

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Bulletin July 2018 - Summary

The El Nino- Southern Oscillation (ENSO) remains neutral and expected to continue to September 2018. The climate models outlooks are indicating the Equatorial Pacific Ocean is slowly warming from the west moving slowly eastward.

In the eastern Pacific, cool anomalies slowly contract eastwards as the Central Pacific trades continue to weaken. This is normally the precursor for an El Nino event. As such, the ENSO outlook is EL Nino WATCH. This means the likelihood of El Nino forming this year is by October to December 2018 is moderate.

Vanuatu may start to experience the impact of El Nino toward the end of its cool and dry season - September and October 2019. During an El Nino event, Vanuatu experiences below-normal rainfall, and drier conditions.

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Bulletin July 2018 - El Nino Oscillation

El Nino Southern Oscillation (ENSO) is currently neutral. The ENSO outlook is on El Nino WATCH.

The Southern Oscillation Index(SOI) remains within the neutral range, but show El Nino - like traits.

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Bulletin July 2018 - MJO

Madden Julian Oscillation (MJO) is weak and near Maritime continent. Forecasts show that it will possibly move into the Western Pacific.

When MJO is in the Western Pacific, it enhances rainfall for 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 July 2018 - Cloud

Outgoing-Long wave Radiation (OLR) - indicates the amount of cloud present. The cloud cover over Vanuatu is near normal during the month of June.
It is also evident that the cloud cover near Southern region was slightly above normal. The islands of the Southern region all had rainfall above-normal in the last month.

Purple - Above average cloud cover
Brown - Below normal cloud cover.

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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 July 2018 - Rainfall

The rainfall anomalies show that rainfall for Northern region was below normal while Southern region was above normal. This is evident in the rainfall records for the month of June.

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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 July 2018 - SST

Warm sub -sea surface temperature continues to spread across the Central Pacific Ocean and also growing deeper moving into June. These are indication of El Nino setting in later this year.

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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 July 2018 - MSLP

The Mean Sea level Pressure (MSLP) anomalies are positive over Vanuatu. below normal to normal anomalies near Fiji and Samoa.

Positive MSLP anomalies indicate high pressure systems that move to Vanuatu, while negative anomalies indicate synoptic low pressure systems and troughs that extend toward Vanuatu from the south east.

Positive MSLP anomalies - Fine and cool weather
Negative MSLP anomalies - Wet and warm weather

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Source

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 July 2018 - Model Outlooks

This model survey points to gradual warming in 2018, with small positive anomalies for June-Aug leading to a possible El Niño late in the year. The dynamical models predict stronger warming than the statistical models for the next 3-5 months. Overall, the models more strongly predict warming than a month ago.

Note the graph is almost one month old.

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Bulletin July 2018 - SPCZ

The South Pacific Convergence Zone is not present over Vanuatu. However, it has contracted further north to Solomon Islands and PNG.

When the SPCZ stretches over Vanuatu, it enhances rainfall.

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