An overview of the present climate in the tropical South Pacific Islands, with an outlook for the coming months, to assist in dissemination of climate information in the Pacific region
Introduction to Island Climate Update 130 - July 2011
El Niño/Southern Oscillation (ENSO)
La Niña in the equatorial Pacific region has ended, and conditions arein the neutral range.
The tropical Pacific is in an ENSO–neutral state, havingcontinued to ease during June. Nevertheless, some weak remnants of the recent strong La Niña event remain. The NINO3 and NINO4 indices for June were +0.3°C and –0.4°C respectively (3-month means +0.2 and 0.4°C). Sub–surface temperature anomalies are positive across the Equatorial Pacific, apart from a shallow near-surface region near the Date Line (within NINO4), and upperocean heat content (top 300m) is also positive right across the Equatorial Pacific.
The tropical cyclone season for 2010–11 has now closed.The ICU forecast for this season inidcated normal or above normal tropical cyclone (TC) activity for most islands west of the International Date Line in the southwest Pacific, with reduced activity east of the International Date Line due to La Niña conditions in the equatorial and tropical Pacific.
Signals in the global climate models continue to showeasing of the rainfall anomalies associated with La Nina that existed this past season. During July – September suppressed convection is expected in the southwest Pacific near Tokelau, which is forecast to receive below normal rainfall in the coming three months. Average or below average rainfall is expected for Tuvalu, the Northern Cook Islands, and Pitcairn Island. Above normal rainfall is forecast for Western Kiribati, Tonga, Niue, and Papua New Guinea.
Sources of South Pacific rainfall data
