National Weather Service Proposes Changes to Excessive Rainfall Outlook
• The National Weather Service (NWS) is proposing updates to its Excessive Rainfall Outlook (ERO) system, aiming to improve forecasting accuracy and public understanding of rainfall risks. The changes include transitioning from a four-tier risk scale to a five-tier system, introducing a new 'Enhanced' category between 'Slight' and 'Moderate' risks. This adjustment aligns the ERO with other national forecast risk graphics. The ERO provides graphical maps predicting the probability of rainfall exceeding Flash Flood Guidance within 25 miles of a point across the contiguous United States for Days 1 through
• The Weather Prediction Center (WPC) synthesizes data from twelve River Forecast Centers to identify rainfall thresholds likely to cause rivers and streams to reach bankfull levels. Public comments on these proposed changes are being solicited through September 5, 2026 (Source: NWS, 2026).
Impact & Risks
The proposed changes aim to enhance public understanding of rainfall risks and improve emergency preparedness. By adding an 'Enhanced' risk category, the NWS seeks to provide more nuanced information about rainfall events that could lead to flash flooding. This adjustment is expected to benefit emergency managers, local governments, and the general public by offering clearer guidance on potential hazards. However, the effectiveness of these changes will depend on public feedback and subsequent implementation (Source: NWS, 2026).
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