Monthly climate

Enhanced convection from the Solomon Islands southeast to Niue

Below average rainfall from Australia to New Caledonia and from Eastern Kiribati to the Cook and Society Islands

The SPCZ moved further south in July, to extend east from the Solomon Islands through southern Tuvalu to the north of Samoa, being displaced south of its mean position. It continued to be weak with little activity further east in the southwest Pacific. In the north, the Inter-Tropical Convergence Zone (ITCZ) moved back to is usual position, enhancing rainfall and cloudiness north of Kiribati.

The large area of enhanced convection that had affected the region from Papua New Guinea to the Solomon Islands in June moved east in July, enhancing rainfall south of the Solomon Islands across Fiji, Samoa Tonga and Niue. Rainfall was at least 125% of average at many locations within these convective regions, some recording more than 200% of average. Rainfall was also above average in the Marquesas Islands of northern French Polynesia.

An extensive region of divergence, with sunny conditions, extended from the region east of the Solomon Islands eastward to Tokelau, including Kiribati, with rainfall less than 75% of average rainfall in many areas.

Rainfall was less than 50% of average from Eastern Kiribati south to the Cook Islands, and Society Islands of French Polynesia. Below average rainfall occurred over much of Australia, extending across to New Caledonia. Willis Island has now recorded 12 consecutive months with less than 75% of average rainfall.

Mean July air temperatures were average or above average over much of our forecast region. However, they were about 0.4°C below average throughout much of New Caledonia. Temperatures were above average in most parts of Fiji with three record high night time temperatures.

Climate extremes in July 2002

Outgoing Long-wave Radiation (OLR) anomalies, in Wm^-2 , for July 2002 represented by shaded areas, and rainfall percentage of average, shown by numbers. High radiation levels (yellow) are typically associated with clearer skies and lower rainfall, while cloudy conditions lower the OLR (blue) and typically mean higher rainfalls. The July 2002 position of the South Pacific Convergence Zone (SPCZ), as identified from total rainfall, is indicated by the solid green line. The average climatological position of the SPCZ is identified by the dashed green line. Data source: NOAA-CIRES Climate Diagnostics Center. Inter-Tropical Convergence Zone (ITCZ), as identified from total rainfall, is indicated by the solid blue line.