Hourly rain rate averages for the 40 most extreme summertime mesoscale convective systems (MCSs) in the current (left) and future climate of the mid-Atlantic region. New research shows that MSCs will generate substantially higher maximum rain rates over larger areas by the end of the century if society continues a 'business as usual' approach of emitting greenhouse gases. Graphic: Andreas Prein / NCAR

By Pam Wright
9 June 2018
(The Weather Channel) – Heavy rainfall from storms has increased by up to 70 percent in some areas of the United States since the 1950s and will only get worse in the coming years, thanks to global warming, scientists say.The 2014 National Climate Assessment reported that downpours from storms are dumping more water across the nation than ever before, with the Midwest, Pacific Northwest and the Upper Plains receiving the greatest increase in heavy rainfall. The Environmental Protection Agency notes that heavy rainfall events have increased by 70 percent in the Pacific Northwest over the past six decades or so, more than any other region in the United States.Andreas Prein of the University Corporation for Atmospheric Research (UCAR) and the National Center for Atmospheric Research (NCAR) says peak rain rates, which arrive when the core of a storm is overhead, have increased across the country by 30 percent over the past 60 years. And while some areas will continue to get wetter from heavy downpours, other regions will get drier.Scientists say the increase in heavy precipitation events is directly linked to human-caused climate change.”Precipitation responds to global warming by increasing,” Angeline Pendergrass, a project scientist at UCAR, said at a conference last week, Business Insider reports.As greenhouse gasses trap heat and warm up the planet, evaporation and subsequent precipitation increase.This trend, known as an intensification of the hydrologic cycle, is only expected to get worse in the coming decades, which will inevitably cause more flooding.In 2017, rainfall from storms amounted to $145 billion in damage, according to Mari Tye, who studies weather extremes at UCAR. Damage incurred from Hurricane Harvey during that same year totaled $125 billion. The storm dumped a record 61 inches of rain on parts of Texas.”A future storm might cause a much, much bigger flood because it produces so much more water,” Prein said. [more]

Heavy Rainfall Has Increased by Up to 70 Percent in Parts of the U.S. Since the 1950s, and It Will Only Get Worse, Experts Say