Submitting Campus

Prescott

Department

Applied Aviation Sciences

Document Type

Article

Publication/Presentation Date

5-2026

Abstract/Description

Sudden Stratospheric Warmings (SSWs) are major disruptions of the wintertime polar vortex that can significantly influence surface weather, including cold air outbreaks (CAOs) across the midlatitudes. This study presents a climatology of SSWs from 1948-2024 using NCEP-NCAR reanalysis data and examines their temporal distribution, relationships with large-scale climate variability, and impacts on surface temperatures in the United States. SSWs are identified using previously published definitions based on the reversal of zonal-mean winds at 60°N and 10 hPa. A total of 44 SSW events were identified, with a strong seasonal preference for January through March. Some decadal variability is observed, though its statistical significance remains uncertain. Analysis of climate indices shows that SSWs occur across all phases of ENSO, with a slight preference for neutral and La Niña conditions, while most events are associated with the negative phase of the Arctic Oscillation (AO), indicating a weaker more disturbed polar vortex. Approximately 80% of SSWs are followed by CAOs in the United States, with impacts occurring either within the first week or four to five weeks after the event, suggesting both immediate and delayed stratosphere-troposphere coupling. However, not all SSWs produce significant surface impacts, and events later in the season are less likely to generate strong CAOs.

Location

Prescott, AZ

Number of Pages

14

Additional Information

Senior Thesis

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