Weather extremes for the Southwest

Increases in areas of the Southwest U.S. affected by drought are likely, according to a report released today by the U.S. Climate Change Science Program.

This is billed as "a scientific assessment that provides the first comprehensive analysis of observed and projected changes in weather and climate extremes in North America and U.S. territories." The report is the first time there has been a specific assessment made across North America.

"Among the major findings reported in this assessment are that droughts, heavy downpours, excessive heat, and intense hurricanes are likely to become more commonplace as humans continue to increase the atmospheric concentrations of heat-trapping greenhouse gases."

Weather changes affecting Arizona and the Southwest are:

• Abnormally hot days and nights, along with heat waves, are very likely to become more common. Cold nights are very likely to become less common.
• Precipitation, on average, is likely to be less frequent but more intense.
• Droughts are likely to become more frequent and severe in some regions.