Monthly climate

Climate developments in April 2003

SPCZ further north, from Tuvalu to the Society Islands

Enhanced convection no longer exists over Kiribati

The SPCZ was displaced further north than average, with enhanced convection over parts of Tuvalu, Tokelau, and the Society Islands of French Polynesia. April rainfall was at least 125% of average (and 300 mm or more in places) over much of this region. Rainfall totals were also 125% or more of average in southern Vanuatu, parts of New Caledonia, the Kermadec Islands northeast of New Zealand, and areas of the Austral Islands in southern French Polynesia.

Rainfall was variable over Fiji. Enhanced convection was also associated with the Inter-Tropical Convergence Zone (ITCZ) in latitudes 8-10° north of the equator.

The last week of April was unsettled with flooding and heavy rainfall totalling over 200 mm in some of Fiji’s Central Division areas, as well as in parts of New Caledonia (288 mm at Ouanaham on the 23rd).

The large region of suppressed convection (associated with rainfall totals generally less than 75% of average) extended further west in April, driven by the equatorial surface easterlies, which occurred in 91% of observations at Tarawa (Western Kiribati), extending from Western Kiribati well to the east of the Marquesas Islands of northern French Polynesia. Suppressed convection also occurred over the Solomon Islands.

Air temperatures were at least 0.5°C above average throughout much of the tropical Southwest Pacific, as far east as Pitcairn Island, but near average in New Caledonia.

Climate extremes in April 2003