Remnants of a powerful Pacific cyclone will trigger dangerous flash flooding across the American Southwest from Monday through Friday as the system drifts inland. Hurricane Polo made landfall on the coast of Baja California Sur on September 28 as a Category 3 storm, bringing sustained winds of 60 to 80 mph and heavy rain to the region.

The National Hurricane Center warned of life-threatening winds and floods in both Sonora and Baja California Sur through Tuesday. Although Polo peaked as a Category 5 and ranks among the strongest cyclones in decades, it will lose its hurricane status before reaching the US border. The storm previously forced port closures and the suspension of classes in Mexico and produced extreme waves in Colima and Cabo.