The Landfall and Inland Penetration of a Flood-Producing Atmospheric River in Arizona. Part I: Observed Synoptic-Scale, Orographic, and Hydrometeorological Characteristics

• DOI: 10.1175/jhm-d-12-0101.1
• Publication Date: 2012-10-18T15:02:42Z
• Authors: Paul J. Neiman; F. Martin Ralph; Benjamin J. Moore; Mimi R. Abel; Kelly M. Mahoney; Jason M. Cordeira; Michael D. Dettinger
• Keywords: Hydrometeorology; Orographic lift; Orography; Cold front; Precipitable water; Winter storm; Forcing (mathematics)

Abstract Atmospheric rivers (ARs) are a dominant mechanism for generating intense wintertime precipitation along the U.S. West Coast. While studies over past 10 years have explored impact of ARs in, and west of, California’s Sierra Nevada Pacific Northwest’s Cascade Mountains, their influence on weather across intermountain remains an open question. This study utilizes gridded atmospheric datasets, satellite imagery, rawinsonde soundings, 449-MHz wind profiler global positioning system (GPS) receiver, operational hydrometeorological observing networks to explore dynamics inland impacts landfalling, flood-producing AR Arizona in January 2010. Plan-view, cross-section, back-trajectory analyses quantify synoptic mesoscale forcing that led widespread state. The show strong formed lower midlatitudes northeastern Ocean via frontogenetic processes sea surface latent-heat fluxes but without tapping into adjacent tropical water vapor reservoir south. profiler, GPS, observations document orographic moist neutral environment within extreme, orographically enhanced precipitation. was oriented nearly orthogonal Mogollon Rim, major escarpment crossing much central Arizona, positioned between high mountain ranges northern Mexico. High melting levels during heaviest contributed region-wide flooding, while high-altitude snowpack increased substantially. characteristics impacted 2010, resulting heavy precipitation, comparable those landfalling coasts midlatitude continents.