The U.S. Southwest Is Moving Toward a Drier Climate, New Study Shows

The southwestern United States is becoming increasingly dry and is likely to stay that way for the foreseeable future as the weather patterns that typically bring precipitation to the region are becoming increasingly rare, according to a new study. Analyzing 35 years of data, researchers from the National Center for Atmospheric Research identified low-pressure systems in the North Pacific as being responsible for bringing moisture to the Southwest. But between 1979 and 2014, those low-pressure systems increasingly gave way to high-pressure systems, which have generally kept precipitation away from the Southwest and have caused drought there and in California. The outlook for the future is not good, said the researchers, writing in the journal Geophysical Research Letters. The shift toward higher pressure in the North Pacific is consistent with climate models, which predict that a belt of higher average pressure that now sits closer to the equator will move north.