GRL Paper - 30-Year Tracking Shows Long-Term Shift To Drier Southwest May Be Here
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Prein, who led the research published on Thursday in Geophysical Research Letters, looked at weather patterns rather than average trends in precipitation. The team identified 12 major patterns, only three of which are favorable for rain in the Southwest. In an ominous finding for the region, they found that over the past 30 years, those three rainy patterns are becoming less frequent and the rains and mountain snow that come with them are drying up.
Less rain and mountain snow in an already dry region is a recipe for severe drought. There’s an 80 percent chance the region could face a megadrought lasting decades as the climate warms, according to research published last year. The new findings reinforce just how serious that threat is. “Nowadays, the droughts are not the same as 30 years ago. They can be more intense and last longer than we would expect 30 years ago,” Prein said.
While Prein did not look directly at whether the current drying was driven by climate change or natural forces, the main climatic driver is an increase in high pressure in the northeast Pacific Ocean that essentially steers stormy weather away from the region. (You might recall a feature called the ridiculously resilient ridge doing something similar and driving the California drought. That’s kinda what’s happening in the Southwest.)
“We would expect something like that from climate change,” Prein said. “The only surprise was that this can be detected in observational datasets.”
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http://wxshift.com/news/southwest-drier-climate-change?utm_content=buffer6a6db&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer
