Southeast Asia & the Pacific: Deficits to emerge on Java; surpluses Vietnam, Malay Peninsula

26 April 2017

The Big Picture
The 12-month forecast through December 2017 (below) indicates extreme to exceptional deficits on Borneo, in southern Sumatra, Java, Sulawesi, and New Guinea.

Surpluses are forecast for the Malay Peninsula.

Impacts
Flooding and landslides triggered by intense rain in Indonesia have left at least six dead and dozens missing. In Aceh Province, the northern tip of Sumatra, 2 deaths were reported, 1 person missing, 1,784 people affected, and 298 homes damaged. Southeast Aceh's Disaster Management Agency dispatched equipment to clear landslide rubble blocking main roads. In nearby North Sumatra Province the Batang Ayumi River overflowed, killing 5 people, damaging 34 houses, washing 7 cars away, and forcing the evacuation of 400 residents. On Java, reports indicate that 38 people are missing and feared buried under a landslide that hit East Java. Indonesia's Social Affairs Ministry initially distributed Rp 1.35 billion (US$101,351), adding an additional Rp 150 billion (US$11.27 million) in aid to East Java landslide victims.

Unseasonably heavy rain struck Ho Chi Minh City, Vietnam in early April, nearly a month before the start of the rainy season, flooding Tan Son Nhat International Airport and washing motorbikes out from under riders as water reached up to one meter (3.28 feet).

At least 9 people died in flooding in Cebu Province, Philippines. Heavy rains caused a river to overflow in Carmen, resulting in 8 deaths; another fatality occurred in Danao City. Tents were erected for more than 200 displaced families, 73 homes were damaged, and 10 people were injured.

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

As blues and greens in the top two maps give way to yellows and oranges in the bottom two, the progression from surplus to deficit conditions is apparent.

For the next three months – April through June – moderate to extreme deficits are forecast to emerge on Java, southern Sumatra, and southern Borneo. Deficits in Cambodia are expected to recede, leaving a pocket of exceptional deficits northeast of Tonlé Sap. Exceptional surpluses will persist in central Vietnam, and surpluses of varying severity are forecast for west-central Myanmar, the Malay Peninsula, northern Sumatra, northeastern Borneo, Mindanao, and Timor-Leste.

From July through September severe to exceptional deficits are forecast in Malaysia, Indonesia, Papua New Guinea, and eastern Mindanao, Philippines. Deficits may be especially intense in West Kalimantan, Indonesia into Sarawak, Malaysia in western Borneo. Surpluses will persist in Thailand’s northern portion of the Malay Peninsula. Moderate deficits are expected to emerge throughout much of Thailand’s mainland extent, in Cambodia, and scattered throughout the remaining areas of Southeast Asia.

The forecast for the latter three months – October through December – is similar to the prior three months, but with the near-absence of any surplus in the region.

(It should be noted that forecast skill declines with longer lead times.)