A study suggests that the annual probability of rainfalls of Hurricane Harvey's magnitude in Texas might increase from 1% during the period from 1981 to 2000 to 18% during the period from 2081 to 2100. Hurricane Harvey produced rainfall averaging approximately 840 mm in the greater Houston metropolitan area. To assess the future likelihood of hurricane-induced rainfall of Harvey's magnitude, Kerry Emanuel embedded a high-resolution, specialized computational hurricane model into coarse-resolution global climate analyses and models. Based on three gridded climate analyses for 1981-2000, the author predicted that Houston would experience a rainfall in excess of 500 mm approximately once every 2000 years; Texas was predicted to experience a rainfall of this magnitude approximately once every 100 years. Six global climate models running Representative Concentration Pathway 8.5, which is a business-as-usual greenhouse gas emissions scenario, predicts that rainfalls greater than 500 mm could occur about once every 100 years by the end of the century in Houston and about once every 5.5 years by the end of the century in Texas. Assuming a linear increase in the frequency of hurricane rains, the models suggest that the current return rate for a rainfall in excess of 500 mm is approximately 325 years for Houston and approximately 16 years for Texas, according to the author.
Article #17-16222: "Assessing the present and future probability of Hurricane Harvey's rainfall," by Kerry Emanuel.