On Using Medium-Range Ensemble Forecasts for Storm Transposition of Synoptic Scale Systems in Probable Maximum Precipitation Estimation

On Using Medium-Range Ensemble Forecasts for Storm Transposition of Synoptic Scale Systems in Probable Maximum Precipitation Estimation | 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 On Using Medium-Range Ensemble Forecasts for Storm Transposition of Synoptic Scale Systems in Probable Maximum Precipitation Estimation Mathieu Mure-Ravaud This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8936099/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Most methods for estimating probable maximum precipitation (PMP)— the greatest depth of precipitation that is physically possible over a given area and duration—rely on storm transposition (ST), the process of transporting a storm, either historically observed or simulated, from its original location to a target basin. Existing ST approaches—whether classical or physically based—involve assumptions and manipulations that can introduce inconsistencies, leaving the physical validity of the transposed storm uncertain. In this study, the internal variability leveraging (IVL) approach is used to transpose an atmospheric river cluster that affected the U.S. West Coast during 20–29 October 2021. Steering the storm toward the target basin and determining its transposition region are achieved by considering an ensemble of plausible storm evolutions and trajectories obtained from archived ECMWF medium-range forecasts. The Willamette River and Nass River watersheds—located approximately 6° N, 2° W and 16° N, 8° W, respectively, from the area most affected by the observed precipitation—were selected as target basins. For each basin, the IVL realization yielding the largest 24-h basin-average precipitation depth was identified, and the initial and boundary condition shifting method was subsequently applied to further enhance its impact, producing 24-h precipitation depths of 119 mm for the Willamette and 98 mm for the Nass. Probable maximum precipitation (PMP) storm transposition medium-range ensemble forecasts atmospheric river Weather Research and Forecasting Model (WRF) Full Text Cite Share Download PDF Status: Posted Version 1 posted 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-8936099","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":609424438,"identity":"1134ff43-b25a-4ae9-b058-c0351d5d257f","order_by":0,"name":"Mathieu Mure-Ravaud","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYJADwwcMDMxgxMDARpwWYwOStZhJQNXj16I77YzZh4977BL7ZyRvq+apsZY3OM7+gOFD2WHcJt/OMZ4541ly4owbaWW3eY6lG244zGPAOOMcfi3MPAeYjRlu5Jjd5m04zDizmYeBmbeNgJY/B+qN5YFaioFa7Gc2sz9g/ktIC8OBw3IGQC3MQC2J/cwMBsyMeLWkFTP2HDguZ3jmWbHknGPpyf3MPAYHe86l49GSvJnhx4FqHrnjyRs/vKmxtm3jP/7wwY8ya5xasIMDJKofBaNgFIyCUYAGAFzpU9+k8y+JAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0003-3612-0373","institution":"UC Davis: University of California Davis","correspondingAuthor":true,"prefix":"","firstName":"Mathieu","middleName":"","lastName":"Mure-Ravaud","suffix":""}],"badges":[],"createdAt":"2026-02-21 23:41:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8936099/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8936099/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109251934,"identity":"e563c7d6-393a-48b6-b639-d178779bca1b","added_by":"auto","created_at":"2026-05-14 09:13:26","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2505000,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8936099/v1_covered_2a228b28-1486-4f95-b3fa-9799d4f08388.pdf"}],"financialInterests":"","formattedTitle":"On Using Medium-Range Ensemble Forecasts for Storm Transposition of Synoptic Scale Systems in Probable Maximum Precipitation Estimation","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Probable maximum precipitation (PMP), storm transposition, medium-range ensemble forecasts, atmospheric river, Weather Research and Forecasting Model (WRF)","lastPublishedDoi":"10.21203/rs.3.rs-8936099/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8936099/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Most methods for estimating probable maximum precipitation (PMP)— the greatest depth of precipitation that is physically possible over a given area and duration—rely on storm transposition (ST), the process of transporting a storm, either historically observed or simulated, from its original location to a target basin. 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