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<br />19 <br />According to the historical baseline (1970-2000), San Leandro’s climate trends suggest that <br />temperatures drop below freezing on average two days per year. Based on climate scenarios, the <br />number of very cold days is expected to decrease and minimum temperatures gradually to rise. Under <br />RCP 8.5, mid-range projections show no days below freezing after 2035 and even the high-range <br />scenario drops to zero days per year by 2095. Even under RCP 4.5, it would be unlikely for San Leandro <br />to experience a day below 32 ◦F after 2064.36 <br />The impacts of climate change on rainfall are ambiguous <br />During the model baseline period of 1970-2000, San Leandro’s typical climate conditions resulted in <br />approximately 18 inches of rainfall per year. By mid-century, under RCP 8.5 (a high emissions scenario), <br />the percent change in total precipitation varies widely between a decrease of 19.6 percent and an <br />increase of 35.8 percent, indicating that no clear directional change in cumulative precipitation volumes <br />is expected by the end of the century. Under both RCP 8.5 and 4.5, mid-range projections of maximum <br />five-day precipitation totals estimate an increase in rainfall of only 15 percent by the end of the <br />century.37 Thus, annual precipitation totals may remain analogous to present conditions in all but the <br />high-end model projections. Figure 12 depicts the projected occurrence of heavy rainfall events in San <br />Leandro between 2020 and 2099. <br />These extreme rainfall event projections may not account for rare, but increasingly intense events such <br />as atmospheric rivers (i.e., Pineapple Express). 38 Studies using computational models suggest that <br />climate change will cause the most intense atmospheric river storms hitting California to become more <br />frequent and last longer by the end of the century.39 <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />36 Reclamation. (2013). <br />37 Reclamation. (2013). 'Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections: Release of Downscaled CMIP5 <br />Climate Projections, Comparison with preceding Information, and Summary of User Needs', prepared by the U.S. Department of <br />the Interior, Bureau of Reclamation, Technical Services Center, Denver, Colorado. <br />38 Shields, C. A., and J. T. Kiehl. (2016). Simulating the Pineapple Express in the half degree Community Climate System Model, <br />CCSM4, Geophysical Research. Letters, 43, 7767–7773, doi: 10.1002/2016GL069476 <br />39 Shields, C. A., and J. T. Kiehl. (2016). <br />63