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The landfall and inland penetration of a flood-producing atmospheric river in Arizona. Part I: observed synoptic-scale, orographic, and hydrometeorological characteristics

Journal of Hydrometeorology

By:
, , , , , , and
DOI: 10.1175/JHM-D-12-0101.1

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Abstract

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

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The landfall and inland penetration of a flood-producing atmospheric river in Arizona. Part I: observed synoptic-scale, orographic, and hydrometeorological characteristics
Series title:
Journal of Hydrometeorology
DOI:
10.1175/JHM-D-12-0101.1
Volume
14
Issue:
2
Year Published:
2013
Language:
English
Publisher:
American Meteorological Society
Contributing office(s):
Branch of Regional Research-Western Region
Description:
25 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Hydrometeorology
First page:
460
Last page:
484
Country:
United States
State:
Arizona