A surge of tropical moisture is forecast to bring heavy rainfall to Southern California and the Southwest from September 18 to 20, 2025, as the remnants of Tropical Storm Mario move inland. By Saturday evening, rainfall totals in some areas of Southern California could approach 2 to 3 inches, with the heaviest amounts focused near the coast and nearby deserts. Also, bands of moderate to heavy rain are spreading across the central and northern Plains, as well as the Upper Midwest, through the same period. Localized flooding is possible in areas where the heaviest rain falls.
