According to World Meteorological Centre Beijing (WMC-BJ), under the combined influence of an upper-level trough and low-level jet stream (Figure 1), it is expected that from May 8 to 10, regions including northwestern Bolivia, southeastern Paraguay, southern Brazil, northern Uruguay, and northeastern Argentina will experience moderate to heavy rainfall from west to east.

Figure1: 500 hPa Geopotential Height (Isopleths) and 850 hPa Wind Field (Wind Barbs) at 12:00 UTC, onMay 9, 2025

Specifically, areas such as Mato Grosso do Sul and São Paulo in Brazil, and Corrientes in Argentina, are likely to see torrential or extreme rain, accompanied by short-range intense rainfall (locally exceeding 60 mm/h), thunderstorms, strong winds, or hail. Total precipitation is expected to reach 30–60 mm in most affected regions, with 80–150 mm in some areas and locally up to 250 mm (Figure 2).

Figure2: Forecasted Accumulated Precipitation from May 8 to 10, 2025 (Unit: mm)

Source: World Meteorological Centre Beijing

Editor: JIANG Zhiqing