Southeast Asia & the Pacific: Water surplus will increase in the Philippines

20 April 2022

THE BIG PICTURE
The 12-month forecast through December indicates near-normal water conditions in much of Southeast Asia and surpluses of varying intensity in many regions in the Pacific though deficits are expected in Sumatra.

In Southeast Asia, moderate to extreme surpluses are forecast in Vietnam from the Central Highlands to the coast and in the nation’s far northwestern corner. Intense surpluses are expected in Peninsular Myanmar, moderating in Peninsular Thailand. Scattered small pockets of surpluses are expected in central Myanmar, along the western coast, and in the lower Irrawaddy region.

Mixed conditions are predicted for Peninsular Malaysia and surpluses in northern Malaysian Borneo and throughout Indonesian Borneo. In Sumatra, widespread deficits are forecast in the center of the island, exceptional surpluses in its northern tip, and moderate to extreme surpluses on the southeast coast. Surpluses of varying intensity are expected throughout Indonesia, the Lesser Sunda Islands, the Malukus, much of New Guinea, and many regions in the Philippines. Surpluses in the central Philippines will be severe to extreme. Elsewhere, anomalies will be exceptional in many pockets including eastern Java, Flores Island, and the Bird’s Head (Doberai) Peninsula of Papua Indonesia. The island of New Britain will see moderate deficits.

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

The forecast through June indicates that surpluses will downgrade somewhat in Southeast Asia though remain widespread, increase in the Philippines and New Guinea, and shrink in Indonesia. Surpluses will be exceptional along Vietnam’s central coastline including Da Nang and pockets in Peninsular Myanmar and Peninsular Thailand. Moderate deficits will emerge northwest of Mandalay, Myanmar but surpluses are expected in Rakhine State in the southwest and in the east along much of the Thai border. Surpluses will be widespread in the Philippines, extreme in the Visayas. Surpluses of lesser intensity are expected in northeastern Borneo, Sulawesi’s northern arm, the Lesser Sunda Islands, and in New Guinea from the central Highlands to the south spanning the border of Papua, Indonesia and Papua New Guinea. Deficits will emerge in Sumatra’s namesake West and North Provinces and will persist in New Britain and in a pocket on Papua New Guinea’s north-central coast.

From July through September, surpluses will nearly disappear in Southeast Asia with a few pockets lingering in Vietnam, northern Laos, and peninsular regions of Thailand and Myanmar. Moderate deficits will persist in a pocket of northwestern Myanmar and will emerge in Peninsular Malaysia near Kuala Lumpur. Deficits will increase in Sumatra though surpluses are expected in some coastal areas of the south. Surpluses will shrink and moderate in the Philippines, persisting primarily in the central region. Surpluses will increase in Indonesia and New Guinea, becoming widespread in Indonesian Borneo and intense in many regions of New Guinea. Deficits in New Britain will shrink and moderate.

The forecast for the final months – October through December – indicates widespread deficits in the Malay Peninsula and Sumatra, and a few pockets in Southeast Asia. Surpluses will be widespread throughout much of Indonesia and New Guinea, and will increase in the Philippines. Moderate surpluses are expected in central Vietnam.

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

IMPACTS
Tropical Storm Megi struck the Philippines in mid-April claiming at least 80 lives in flooding and landslides. Much of the damage was in the central province of Leyte where mud buried most of the coastal village of Pilar. In Baybay City, 48 died, 100 were injured, and many remain missing.

Repeated rainstorms earlier in the month triggered flooding and landslides in several other regions of the nation, killing one person, affecting around 3,000, forcing schools to close, and damaging homes and infrastructure.

In southern Thailand, 200 water buffalo died in Thale Noi Waterfowl Park, the largest wetland in the country, after months of flooding destroyed their grassland pasture leaving most of the animals to starve. Those that didn’t starve were simply too weak to survive and drowned in the floodwaters. Several hundred other emaciated buffalo were rescued.

Also in the south, one man drowned while fishing in a flooded rice paddy. Several days of torrential rainfall inundated the field with 70 centimeters (27 inches) of water.

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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