Southeast Asia & the Pacific: Widespread moderate surpluses will persist

21 July 2022

THE BIG PICTURE
The 12-month forecast through March 2023 indicates widespread surpluses of varying intensity in several regions of Southeast Asia and surpluses in many pockets throughout the Pacific. Deficits are forecast in Sumatra and Papua New Guinea.

In Myanmar, surpluses of varying intensity are forecast throughout much of the nation with a pocket of transitional conditions (pink/purple) on the Irrawaddy River near Mandalay. Near-normal water conditions are forecast for most of Thailand though surpluses are expected south of the Mun River along the Cambodian border and in much of Peninsular Thailand. As well as surpluses on its Thai border, Cambodia will see moderate surpluses in its eastern half. Surpluses will be widespread and severe in northern Laos and northern Vietnam, reaching extreme to exceptional intensity in Vietnam’s northeast near the Chinese border. Generally moderate surpluses are expected in Vietnam’s South Central Coast region and Central Highlands.

In the Philippines, severe surpluses are predicted for northern Luzon and the central islands.

Though normal water conditions are forecast for most of Malaysia, a few anomalous pockets are expected including moderate deficits south of the Kuching metropolitan area on Borneo and surpluses in the northeast. Surpluses are predicted for several regions of Indonesian Borneo as well and will be particularly widespread in the southwest. Surpluses are also forecast in pockets of Sulawesi, the Maluku Islands, Java, the Lesser Sunda Islands, and several regions along Papua, Indonesia’s south coast.

Sumatra is forecast to experience moderate to extreme deficits around the city of Medan in the north and in the central region of the island. Deficits are also forecast in Papua New Guinea along its north coast, and in New Britain and the Solomon Islands.

FORECAST BREAKDOWN
The 3-month maps (below) show the evolving conditions in more detail.

The forecast through September indicates that surpluses will shrink and downgrade but remain widespread. Anomalies are expected to be moderate overall but with some pockets of greater intensity. In Southeast Asia, surpluses of varying intensity are forecast in Myanmar and near-normal conditions in much of Thailand. Generally moderate surpluses are expected in: northern Laos; northern Vietnam, its narrows, and the Central Highlands into Cambodia; and the central Thai-Cambodian border and southeastern Cambodia. Deficits are forecast in pockets of western Cambodia. Surpluses are forecast in much of Indonesia and Malaysian Borneo. Anomalies will be intense in pockets of Java and Flores Island. A pocket of moderate deficit is forecast in central Sumatra, but deficits will be more intense in New Guinea on the north coast, Bird’s Tail Peninsula (Papuan Peninsula), and pockets on the Gulf of Papua, as well as in New Britain and the Solomon Islands.

From October through December, surpluses will shrink considerably in Southeast Asia with moderate anomalies persisting in Vietnam’s South Central Coast and Central Highlands, and southern Laos. Moderate to extreme deficits are forecast for Peninsular Malaysia and Sumatra, while deficits in New Guinea shrink and moderate. New Britain and the Solomons, however, will continue to see deficits. Surpluses are expected in pockets of the Philippines, coastal Indonesian Borneo, Sulawesi, the Lesser Sundas and Malukus, and western and southern New Guinea.

The forecast for the final months – January through March 2023 – indicates deficits in Sumatra and Peninsular Malaysia. Surpluses are forecast in the Central Highlands of Vietnam and pockets in the Philippines, Sulawesi, the Lesser Sundas and Malukus, and coastal New Guinea.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
Heavy rainfall in early July triggered flooding and landslides in the Philippines. One death was reported in Bataan Province and nearly 40,000 people were affected nation-wide. Many homes and buildings were destroyed.

Flooding and landslides also struck the Maluku Islands, killing seven people. The capital, Ambon City, sustained damages to dozens of homes and buildings, while damages in other areas were much higher and included homes, schools, and a hospital.

Excessive rainfall has continued to wreak havoc in Southeast Asia as well, damaging thousands of hectares of ripe and newly planted rice in the Mekong Delta.

Lectures were suspended at a university in Bangkok, Thailand after torrential rainfall flooded the campus. And in northern Thailand, a bridge collapsed stranding Buddhist monks who zip-lined to safety across the swollen Mae Samat River.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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