East Asia: Water surpluses to persist in southeastern China

16 August 2019

THE BIG PICTURE
The 12-month forecast for East Asia through April 2020 indicates widespread, intense water surpluses in southeastern China including exceptional surpluses in Guangxi, Hunan, Jiangxi, and Fujian.

Surpluses will also be widespread and intense in northwestern Sichuan, Qinghai, and western Tibet (Xizang).

ISciences_East_Asia_Composite_Adjusted_201905-202004_12mo_panel.png

Moderate surpluses are expected along the Lower Reaches of the Yellow River (Huang He), and severe to extreme surpluses along the Ordos Loop. Severe surpluses are forecast in Heilongjiang Province in northeastern China.

Intense deficits are expected in the Shandong Peninsula in the east, with deficits of varying intensity reaching across the Bohai Sea to Liaoning Province. Intense deficits are also forecast for the eastern Tarim Basin in Xinjiang in the west, and pockets of southern Sichuan. Moderate deficits are forecast for southern Yunnan.

Deficits are forecast for much of the Korean Peninsula and could reach exceptional intensity around Pyongyang. In Japan, severe to exceptional deficits are expected in northernmost Honshu and in Hokkaido, and some moderate surpluses in eastern Honshu.

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

The forecast through October indicates that deficits will shrink and downgrade considerably in the region, with exceptional deficits retreating entirely from the Shandong Peninsula and the interior past the North China Plain, as well as from Yunnan where a transition to moderate surplus is forecast. Intense deficits will emerge, however, in eastern Xinjiang, and moderate deficits in a pocket of northern Inner Mongolia. Primarily moderate deficits are forecast for pockets of the Korean Peninsula. Deficits in northern Japan are expected to shrink and downgrade somewhat.

ISciences_East_Asia_Composite_Adjusted_201905-202004_3mo_panel.png

Surpluses in southeastern China will remain widespread and the extent of exceptional anomalies will shift east, affecting Fujian, Jiangxi, and northern Guangxi. Surpluses will shrink and moderate on the Ordos Loop of the Yellow River, and in Sichuan, Qinghai, and Xinjiang. Surpluses in Tibet will shrink but remain exceptional in the west.

From November 2019 through January 2020, normal conditions will return to many parts of East Asia. Surpluses will shrink and moderate in southeastern China, but remain widespread from eastern Guizhou through Hunan, Jiangxi, northern Fujian and southern Zhejiang. Surpluses will disappear from the Ordos Loop of the Yellow River; shrink but persist in the river’s Upper Reaches; and persist in northeastern China and western Tibet. Primarily moderate deficits will persist in a few pockets of North Korea, and will emerge along a scattered path from Xinjiang in western China through much of Inner Mongolia and southern Mongolia, interspersed with conditions of both deficit and surplus (pink/purple) as transitions occur. Nearly normal conditions are forecast for South Korea and Japan.

The forecast for the final three months – February through April 2020 – indicates mild surpluses in southeastern China; surpluses of varying intensity in the northeast, Qinghai, and western Tibet; and a slight uptick in the intensity of deficits in eastern Xinjiang.

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

IMPACTS
At least one person was killed and 40 others injured when Tropical Storm Krosa lashed Japan with torrential rains in mid-August. The third tropical cyclone to hit Japan in three weeks, Krosa dropped over 850 mm (33 inches) of rain the day it landed in Japan’s Kochi Prefecture.

Typhoon Francisco killed at least one person in southern Japan early this month. Tropical Storm Nari struck the southern part of Mie Prefecture in late July, dropping as much as 47.5 mm (1.9 inches) of rain in an hour. Days prior, Tropical Storm Danas drenched some parts of western Japan with nearly 300mm (11.8 inches) of rain, prompting evacuation orders to tens of thousands of residents.

Typhoon Lekima struck eastern China this month, causing flooding and landslides which killed at least 48 people and forced over a million to evacuate. Most people were killed when a landslide backed up a river, causing it to rise ten meters (33 feet) in ten minutes. Lekima was the ninth typhoon to hit China this year. Direct economic losses were estimated at 14.57 billion yuan (USD $2.07 billion), according to state media.

Flash flooding in central China killed at least ten people at a scenic gorge early this month.

Tropical Storm Wipha flooded the Hainan and Guangdong provinces in southwestern China, and the Guangxi region in south China, early this month, causing mudslides that blocked roads and waterways.

Heavy downpours raised water levels of major Mongolian rivers above warning levels, and reportedly led to nearly 30 drowning incidents in July.

Drought has cut tea production by half this year on some plantations in southwest China.

Eastern China’s Jiangsu province is amid its worst drought in 60 years, drying regional lakes and rivers.

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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