Objective

Arid and semi-arid regions located in subtropical zones are projected to experience some of the most adverse impacts of climate change. The Southwest United States is generally representative of this type of climate and is strategically important in that it houses some of the most spatially expansive and important military installations in the country. In addition to concerns regarding future water resource availability, an increase in extreme weather events will directly affect physical infrastructure and operational capability for the Department of Defense (DoD). Observational evidence shows that significant increases in precipitation intensity already have occurred in North America and worldwide. Most extreme weather impacts in the Southwest United States of DoD concern are associated with severe thunderstorms during the North American monsoon in late summer, and these include hail, flash flooding, high winds, dust storms, and lightning. Current climate change projection models, however, cannot resolve the North American monsoon as a climatological feature, much less the individual thunderstorms that would cause severe weather.

The objective of this project is to evaluate how warm season extreme weather events may change in the Southwest United States and how these changes may affect DoD facilities within the region. High resolution regional atmospheric model simulations of extreme weather events within the recent past and future will be used to inform possible changes in severe storm frequency and intensity. Relevant metrics from these simulations relating to operational severe weather hazards will then be considered for climate change impacts assessment purposes.