Heat Dome Drives Prolonged Heat Wave in China

A prolonged heat wave is bearing down on central and eastern China, with forecasters warning of another weekend of “sauna-like” conditions and temperatures above 38°C in parts of the middle and lower Yangtze River. State media and meteorologists have identified a persistent “heat dome” as a key driver of the extreme conditions, even as experts caution that the term is a vivid description rather than a formal meteorological classification.

Context

The current heat is the product of stable high-pressure systems. According to China Weather Network via Xinhua, the western Pacific subtropical high has pushed northwestward, drawing warm, moist air from the Pacific and the South China Sea deep into the mainland. The result is high humidity stacked on top of high temperatures — the muggy “sauna days” that have enveloped broad areas of central and eastern China since mid-July.

Key Developments

Chongqing has been an epicenter of the heat. As of July 31, the southwestern metropolis had recorded 27 high-temperature days in July, tying its local historical record for the month, the same report said. Forecasters expect little relief in the coming days.

The heat has also reached unusually far north. Overnight temperatures in Changchun, Jilin, and Shenyang, Liaoning, broke local July records on July 30-31, according to Xinhuanet. Shenyang recorded its first high-temperature day of the year on July 31 and is forecast to hover near 34°C this weekend, with a possible four-day streak of high temperatures early next week. In Hangzhou, high temperatures are expected every day for the coming week, with nighttime minimums near 30°C, leaving little respite even after dark.

At the same time, the edge of the subtropical high is channeling moisture into the Sichuan Basin, southern Shaanxi, Heilongjiang, Guangdong, and Guangxi, where heavy rainstorms are forecast through the weekend. According to Beijing Daily, the same weather systems linked to heat domes — blocking highs and subtropical highs — can also drive intense rainfall when warm, moist air meets cooler air.

Analysis

The “heat dome” label has made this summer’s weather a global talking point, but meteorologists say precision matters. In a People’s Daily explainer republished by Xinhua, Liu Xiaobo, chief forecaster at the Central Meteorological Observatory, said the recent high temperatures in northwest and north China were triggered by a high-pressure ridge, not by a heat dome directly. “Heat dome,” he explained, is a description of extreme-heat phenomena rather than a precisely defined meteorological term.

Under such systems, air subsides and warms, clouds are suppressed, and solar radiation is intense. Because horizontal and vertical mixing is limited, heat accumulates near the surface. The CCTV explainer republished by Beijing Daily compares the effect to a giant lid: external cold air cannot enter, and trapped hot air cannot escape, producing sustained heat waves that often exceed 40°C. It also notes that a weakened, wavy jet stream allows high-pressure systems to stall, and that global warming is increasing the likelihood of such persistent patterns.

The immediate concern, however, is compound risk. Consecutive rainfall in the Sichuan Basin, Heilongjiang, Guangdong, and Guangxi has created a significant “stacking effect,” raising the danger of flash floods and geological disasters. The same high-pressure configuration that bakes one region can unleash torrential rain in another, testing emergency response systems across multiple provinces.

What’s Next

With the subtropical high expected to remain in control into early next week, central and eastern China faces an extended stretch of oppressive heat punctuated by violent downpours. For millions of residents, the most pressing issue is health: high nighttime temperatures and humidity intensify heat stress, especially in cities such as Chongqing, Hangzhou, and Shenyang. The longer-term question, experts suggest, is whether stalled high-pressure systems — and the “heat domes” they create — are becoming a more common feature of northern hemisphere summers.