Figure 1: 1-month SPI for July 2023 (reference period, 1991-2020)
Figure 2: SSTA across the Pacific and Indian Ocean for July 2023 (reference climatology, 1991-2020, JMA-iTacs)
Areas of Concern: Thailand, Cambodia, northern parts of Lao PDR and Vietnam, Southern Philippines and the Eastern sections of Indonesia
Areas of moderate to severe rainfall deficiencies have been observed in some parts of Southeast Asia region, in particular over Thailand, Cambodia,northern parts of Lao PDR and Vietnam, Southern Philippines and the Eastern sections of Indonesia as shown in Figure 1. This dry condition was consistent with 3-month below-normal rainfall being experienced for the period May 2023 – July 2023 (see attached 3-month SPI). Other parts of Southeast Asia recorded moderate rainfall deficiencies, but these were not as extensive.
In July, above average sea surface temperature anomalies (SSTAs) across the central and eastern equatorial Pacific further strengthened. The strong warming at the eastern equatorial Pacific were consistent to observe more than 3ºC warmer than average and expanding westward. However, near average SSTAs were observed in most of the western Pacific, east of the Philippines while in the South China Sea and around Indonesia, positive anomalies were also evident.
The IOD value were still within neutral levels for July, with the western equatorial Indian Ocean showing slightly warmer than average than the eastern equatorial Indian Ocean.
Inactive phase of the Madden–Julian Oscillation (MJO) over the Maritime Continent in July was observed characterized by suppressed convection and precipitation in most areas of the region.