Argentina and Brazil Experience Persistent Heavy Rainfall

Over the past three days, parts of central and northern Argentina, central and eastern Paraguay, Uruguay, and southern Brazil have experienced moderate to heavy rain, with localized downpours. Accumulated precipitation has reached 40-120 mm, with some areas exceeding 200 mm (Figure 1).

It is forecasted that over the next three days (September 2-4), influenced by the eastward movement of a cold vortex system (Figure 2), parts of northeastern Argentina, southern Paraguay, southern Brazil, and northern Uruguay will experience moderate to heavy rain, with localized downpours. The cumulative precipitation is expected to reach 50-80 mm, with some areas exceeding 100 mm (indicating a certain level of extremity, Figure 3). Additionally, regions in eastern Argentina and eastern Brazil will face winds of 4-6 on the Beaufort scale, with gusts exceeding 7. Attention should be given to the potential for secondary disasters such as urban flooding due to the persistent rainfall.

Figure 1  Accumulated Precipitation from August 30 to September 2, 2025, 00:00 UTC (Unit: mm)

Figure 2  500 hPa Geopotential Height (Isopleths) and 850 hPa Wind Field (Wind Barbs) at 00:00 UTC, September 4, 2025

Figure 3  Forecasted Accumulated Precipitation from September 2 to September 5, 2025, 00:00 UTC (Unit: mm)

Author: Hu Yingying                                 Reviewer: Ma Jie 

English reviewer:Wang Yi                                                                       Issue approver:Dai Kan