According to World Meteorological Centre Beijing, affected by a surface cyclone and cold air (Figure 1), heavy to very heavy rain is expected in the central and eastern United States from April 21 to 22. Specifically, parts of Illinois, Indiana, Missouri, Oklahoma, and Texas will experience torrential rain or severe downpours, accompanied by short-duration intense rainfall, thunderstorms, strong winds, and tornadoes. Accumulated precipitation is forecasted to range from 20 to 40 mm, with some areas receiving 60 to 80 mm, and localized totals exceeding 100 mm (Figure 2). These regions will also experience winds of 4 to 6 on the Beaufort scale, with gusts reaching 7 to 9, and in the southwestern and southern coastal areas of the U.S., gusts could reach 10 to 11 (Figure 3). Additionally, parts of Canada and the eastern U.S. will see temperature drops of 6 to 10°C, with localized decreases of 12 to 16°C.

Figure 1: 500 hPa Geopotential Height (Contour Lines) and 850 hPa Wind Field (Wind Barbs) at 08:00 UTC, April 21, 2025

Figure 2: Forecasted Accumulated Precipitation from April 19-22, 2025 (Unit: mm)

Source: WMC-BJ

Editor: LIU Shuqiao