今年来暴雨范围最大、最强降水将登场，局地日雨量或破5月极值！

Core Viewpoint - A new round of heavy rainfall, the strongest of the year, is set to impact a large part of southern China starting tomorrow night, with significant risks of disasters due to extreme rainfall levels [1][6]. Group 1: Rainfall Intensity and Characteristics - The rainfall from the 27th to the 29th will see areas in Guizhou, Jiangnan, and southern China experiencing heavy to torrential rain, with some regions receiving 100 to 180 millimeters, and localized areas potentially reaching 250 to 300 millimeters [1][6]. - Short-duration heavy rainfall is expected, particularly in regions like Guizhou and southeastern Fujian, where localized rainfall could exceed 80 millimeters in a short time [3][10]. - The current rainfall system is characterized by a low vortex shear line moving eastward, combined with moisture from the Bay of Bengal and the South China Sea, leading to optimal conditions for heavy rainfall [6][10]. Group 2: Affected Areas and Coverage - The rainfall will cover a vast area, with heavy rain expected across multiple provinces including Guangxi, Guangdong, Hunan, Jiangxi, Fujian, and Zhejiang, marking the largest affected area this year [5][11]. - The rainfall intensity and coverage are anticipated to surpass previous rainfall events, with significant overlap in affected areas from earlier rainfall events [11][13]. Group 3: Disaster Risks and Historical Context - The overlapping of heavy rainfall zones increases the risk of mountain floods, geological disasters, and urban flooding, necessitating heightened vigilance and risk assessments in affected regions [11][13]. - Since May, southern China has experienced five rounds of significant rainfall, with some areas seeing precipitation levels 30% to 80% above normal for this time of year, and localized areas experiencing up to double the usual amounts [13].