Beyond extratropical cyclones: Large-scale control on atmospheric river landfall in the western United States

Beyond extratropical cyclones: Large-scale control on atmospheric river landfall in the western United States | 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 Article Beyond extratropical cyclones: Large-scale control on atmospheric river landfall in the western United States Chanil Park, Yi Ming This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7068167/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications Earth & Environment → Version 1 posted You are reading this latest preprint version Abstract Atmospheric rivers (ARs) play a crucial role in extreme precipitation and water resources management in the western United States. Their occurrence has been widely attributed to extratropical cyclones. Here, we find that landfalling ARs in this region are not merely synoptic-scale phenomena but are also driven by large-scale circulation. Specifically, quasi-stationary Rossby waves with centers of action along the Eurasian and North American coasts form a newly identified circum-North Pacific pattern. This teleconnection pattern channels subtropical moisture toward the U.S. West Coast on intraseasonal timescales, enabling its constructive interference with extratropical cyclone-induced moisture transport. The resulting “intermediate” ARs account for up to twice as much winter precipitation as purely synoptic ARs. Moreover, they exhibit a stronger correspondence with high-category AR events. This previously unrecognized multiscale process deserves greater attention for the skillful prediction of ARs and the improved understanding of their variability and projected changes. Earth and environmental sciences/Climate sciences/Atmospheric science/Atmospheric dynamics Earth and environmental sciences/Climate sciences/Hydrology Full Text Additional Declarations There is NO Competing Interest. Supplementary Files 22.SupplementaryVideo1caption.docx Caption for the supplementary Video 1 23.SupplementaryVideo1.gif Supplementary Video 1 21.Supplementary.docx Supplementary figures Cite Share Download PDF Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications Earth & Environment → 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. 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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-7068167","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":503936944,"identity":"e54fd908-d760-4877-8988-ad36e82b0707","order_by":0,"name":"Chanil 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