Sponsor
Funding for this work was provided by the National Science Foundation AGS-2206997 (P.C.L. and S.B.), NSF #2206996 (D.S.) and AGS-PRF #2403765 (D.A.K.). We thank Dr. Xiaoyu Bai for data support and Brianne Suldovsky for helpful considerations in communicating extreme heat. We acknowledge current and former members of the Portland State University Climate Science Lab for their contributions.
Published In
Weather and Climate Extremes
Document Type
Article
Publication Date
5-17-2026
Subjects
Heat Domes -- North America, Climatology
Abstract
The term heat dome in reference to extreme heat events has grown in popularity. While a heat dome definition has recently been added to the Glossary of the American Meteorological Society, a quantitative meteorological definition is currently lacking. Here we present such a definition and use it to develop a novel 85-year climatology of extreme heat and associated mid-tropospheric circulation over mid-latitude North America. Our definition groups extreme heat objects (EHOs), defined daily as spatially contiguous regions where 2-m maximum temperature exceeds the May-September 99th percentile, into two categories: those directly associated with a 500-hPa closed anticyclone and those that are not. When a closed anticyclone is closely associated with an EHOs on the same day this is labeled a heat dome, with EHOs occurring under these features classified as heat dome EHOs. While heat domes occur across the continent, they are most common south of about 45° north latitude. Overall, 47.1% of EHOs detected are heat dome EHOs. However, when EHOs are considered part of multi-day heat events, 69% are heat dome EHOs. Non-heat dome EHOs occur with a variety of 500-hPa patterns, often, but not always, resembling an open ridge. This illustrates that very extreme heat, relative to climatology, can occur without being part of a heat dome feature and therefore the term should only be used in reference to a specific type of meteorological phenomenon. Results provide insight into the atmospheric drivers of extreme heat with potential to promote more meteorologically precise communication about extreme heat risk.
Rights
Copyright (c) 2026 The Authors
This work is licensed under a Creative Commons Attribution 4.0 International License.
Locate the Document
DOI
10.1016/j.wace.2026.100913
Persistent Identifier
https://archives.pdx.edu/ds/psu/44699
Publisher
Elsevier BV
Citation Details
Loikith, P. C., Bigalke, S., Taylor, G. P., Kalashnikov, D. A., Singh, D., & Laverty, A. (2026). A climatology of heat domes over North America. Weather and Climate Extremes, 53, 100913.