'Considerable Flash Flood Warning' as 5-7 inches of rain expected in metro New Orleans If 5-7 inches fall, as predicted, the system would be overwhelmed and water would rise in low-lying areas of the city. Author: WWL Staff Updated: 8:57 AM CDT May 10, 2021 NEW ORLEANS — Up to 7 inches of rain could fall on New Orleans Monday morning, bringing heavy street flooding and other dangerous conditions. The National Weather Service issued what it called a "Considerable Flash Flood Warning" for the New Orleans metro area as several lines of storms have moved through the area or are lining up and heading east.