Island Climate Update 198 - March 2017
Download the PDF: Island Climate Update 198
The tropical Pacific is currently in an ENSO (El Niño – Southern Oscillation) neutral state. Sea surface temperatures (SSTs) in the central equatorial Pacific Ocean remain near or slightly below average, with a value of -0.09°C in the NINO3.4 region for the month of February.
In the sub-surface ocean, warmer than average temperatures (+2.0°C anomalies) are present in the western equatorial Pacific but remain near or slightly below average across the central and eastern equatorial Pacific.
The Southern Oscillation Index (SOI) is close to zero with a value of -0.2 for February 2017. While large-scale circulation patterns are generally consistent with an ENSO-neutral state, ongoing rounds of equatorial westerlies may suggest an atmospheric tendency toward a future El Niño event.
International guidance favours ENSO-neutral conditions with high probability (85% chance) over the next three month period (March-May 2017). Later during the year, the chances for a return to El Niño conditions increase substantially to reach over 50% in August – October 2017. Note however that ENSO forecasts going beyond the northern hemisphere spring are known to be less reliable than at other times of the year (the so-called “spring predictability barrier”).
March to May 2017 rainfall forecast
Regional drought potential advisory
Based on rainfall anomaly classification over the past six months and forecast rainfall anomaly classification over the next 3 months
Nauru, Kiribati: Below or well below normal rainfall experienced over the past 6 months in the Gilbert Islands and Nauru and 5 of the past 6 months in the Line and Phoenix Islands. Below normal rainfall is forecast over the next 3 months.
Tokelau, Tuvalu: Below normal rainfall experienced over 5 of the past 6 months in Tokelau and 4 of the past 6 months in Tuvalu. Normal or below normal rainfall is forecast over the next 3 months.