Warming climate would also boost individual storm intensity
December 5, 2016 National Center for Atmospheric Research/University Corporation for Atmospheric Research ScienceDaily
At century’s end, the number of summertime storms that produce extreme downpours could increase by more than 400 percent across parts of the United States — including sections of the Gulf Coast, Atlantic Coast, and the Southwest — according to a new study by scientists at the National Center for Atmospheric Research (NCAR).
The study, published in the journal Nature Climate Change, also finds that the intensity of individual extreme rainfall events could increase by as much as 70 percent in some areas. That would mean that a storm that drops about 2 inches of rainfall today would be likely to drop nearly 3.5 inches in the future.
“These are huge increases,” said NCAR scientist Andreas Prein, lead author of the study. “Imagine the most intense thunderstorm you typically experience in a single season. Our study finds that, in the future, parts of the U.S. could expect to experience five of those storms in a season, each with an intensity as strong or stronger than current storms.”…
….A surprising result of the study is that extreme downpours will also increase in areas that are getting drier on average, especially in the Midwest. This is because moderate rainfall events that are the major source of moisture in this region during the summertime are expected to decrease significantly while extreme events increase in frequency and intensity. This shift from moderate to intense rainfall increases the potential for flash floods and mudslides, and can have negative impacts on agriculture….
The figure shows the expected increase in the number of summertime storms that produce extreme precipitation at century’s end compared to the period 2000 – 2013. Credit: Andreas Prein
Andreas F. Prein, Roy M. Rasmussen, Kyoko Ikeda, Changhai Liu, Martyn P. Clark, and Greg J. Holland. The future intensification of hourly precipitation extremes. Nature Climate Change, December 2016 DOI: 10.1038/NCLIMATE3168