High-resolution Climate Projections over Minnesota for the 21st Century

Minnesota is the state with the strongest winter warming in the contiguous United States. We performed regional climate projections at 10 km horizontal resolution using the Weather Research Forecasting model forced with eight CMIP5 GCMs. The selected GCMs have previously been found to be in relatively good agreement with observations over Minnesota compared to other members of the CMIP5 model ensemble. Our projections suggest ongoing warming in all seasons, especially in winter, as well as shallower snow depth and fewer days with snow cover. We expect significant increases in spring and early summer heavy precipitation events. Our comparisons between different time slices and two different emission scenarios indicate a climate for the state of Minnesota near the end of the 21st century that is significantly different from what has been observed by the end of the 20th century. Winters and summers are expected to be up to 6 and 4 degrees C warmer, respectively, over northern and central Minnesota, and spring precipitation may increase by more than 1 mm d(-1) over northern Minnesota. Especially over the central part of the state, winter snow depth is projected to decrease by more than 12 cm, and the number of days per year with snow depth of more than 2.54 cm (one inch) is expected to decrease by up to 55. Plain Language Summary Minnesota is the state with the strongest winter warming in the contiguous United States. We performed regional projections of the climate across Minnesota for the middle and end of the 21st century. We selected the results from eight recent global climate model projections to calculate climate data over an area of 10 km by 10 km with a regional climate model. Our results indicate that the future climate for the state of Minnesota is likely to be significantly different from what has been observed near the end of the 20th century. Over northern and central Minnesota, winters and summers are expected to be up to 6 and 4 degrees C warmer, respectively, near the end of the 21st century. Spring precipitation may increase by more than 1 mm d(-1) over northern Minnesota. Over the central part of the state, winter snow depth is suggested to decrease by more than 12 cm. The number of days per year with snow depth of more than 2.54 cm (one inch) is expected to decrease by up to 55. These results are expected to influence regional decision-making related to agriculture, infrastructure, water resources, and other sectors.