Verifying WPC Excessive Rainfall Outlooks across three hurricanes of varying rainfall impact

Verifying WPC Excessive Rainfall Outlooks across three hurricanes of varying rainfall impact | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Verifying WPC Excessive Rainfall Outlooks across three hurricanes of varying rainfall impact Alexandra Music, J. Marshall Shepherd This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6674870/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 11 Feb, 2026 Read the published version in Natural Hazards → Version 1 posted 5 You are reading this latest preprint version Abstract Atlantic basin hurricanes drive serious meteorological hazards for the southeast United States, including rainfall-induced flooding. The well-known Saffir-Simpson Hurricane Wind Scale communicates only wind hazard, creating the potential for low wind, high rainfall storms to be perceived as mild. Researchers have emphasized the need to center rainfall hazard in hurricane warning messaging, and prerequisite to this is verifying the accuracy of hurricane rainfall forecasts. This paper investigates the characterization of forecasted and observed rainfall for three Atlantic hurricanes with varying rainfall impact: Florence (2018), Michael (2018), and Ian (2022). We first quantified, visualized, and compared the distribution of daily and total rainfall for each storm to establish the concept of varied rainfall impact. By a Mann-Whittney U Test, we found that the distributions of total rainfall for Florence/Michael and Florence/Ian were significantly different while differences between Michael/Ian were not significant. We then compared Excessive Rainfall Outlooks (EROs) against a flash flood proxy both visually and through fractional coverage calculations. We used these to calculate fractions brier scores (FBS) and fractions skill scores (FSS) using old and new ERO definitions. New ERO definitions improved FSS scores across all hurricanes. Florence had the highest FSS, followed by Michael, then Ian, though all scores were deemed skillful. To the authors’ knowledge, this is the first instance of FSS scores used for ERO verification. These findings provide a framework for a wider study on forecast verification across hurricane rainfall scenarios, a key step towards improving how we communicate and characterize these hazards. Hurricanes Precipitation Forecast Verification Rainfall Impacts Excessive Rainfall Outlook Full Text Cite Share Download PDF Status: Published Journal Publication published 11 Feb, 2026 Read the published version in Natural Hazards → Version 1 posted Reviewers agreed at journal 18 Jun, 2025 Reviewers invited by journal 17 Jun, 2025 Editor invited by journal 15 Jun, 2025 Editor assigned by journal 16 May, 2025 First submitted to journal 15 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6674870","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":472332818,"identity":"88bc8326-f355-483a-9edc-0b2df55e63a4","order_by":0,"name":"Alexandra Music","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBElEQVRIiWNgGAWjYDACdgjFAyIOALEcmPEAnxZmZC1APcZgRgIRWiAAqCWxAcTAp4W/mfmY1M22Ohn+GbkPD3+oqEufH3b4IdAWOzndBuxaJA6zJRvnth3mkbiRbnDgwJnDuRtvpxkAtSQbmx3AYc1hHsPHuW0HeAyk0xgOHGw7kLtxdgJIy4HEbTi0yB/m/3A4t60OquVfXbrh7PQPeLUYHOZhBNrCDNXSwJwgL52D3xbDw2zGxjnngH65/4zhwJljhw03SOcUHEgwwO0XuePNz6Rzyurs+XuOMX+oqKmTl5+dvvnDhwo7OZzex3QqWKUBscpBQL6BFNWjYBSMglEwEgAAQfNjoZw4rF8AAAAASUVORK5CYII=","orcid":"https://orcid.org/0009-0000-7094-8460","institution":"University of Georgia Department of Geography","correspondingAuthor":true,"prefix":"","firstName":"Alexandra","middleName":"","lastName":"Music","suffix":""},{"id":472332819,"identity":"f4a03dbc-4c27-4c3c-a01d-a7c61b29db71","order_by":1,"name":"J. 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