The average simulated rainfall for RCP4.5 is 10.2 mm (0.4 in.) greater than the current climate simulation, with a maximum grid point difference of 235.7 mm (9.28 in.). Spatial patterns of accumulated rainfall show that RCP4.5 portrays a better-defined north-to-south rainfall maximum inland from the coastline than the current climate simulation, suggesting that RCP4.5 produced a better-defined and stronger sea breeze than the current climate simulation.
The average simulated rainfall for RCP8.5 is lower than RCP4.5, which is counterintuitive given the warmer conditions assumed by RCP8.5 compared to RCP4.5. The spatial rainfall patterns in RCP8.5 suggest that the sea-breeze front did not advance as far inland as it did during RCP4.5 and is less well defined, which may explain the lower rainfall accumulations.
Despite inconsistencies when comparing accumulated rainfall to simulated radar reflectivity, the model runs suggest that future climates may be able to generate high, localized rainfall totals, even though the overall spatial averages may be lower than those in the present-day climate.
IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp. doi:10.1017/CBO9781107415324.
Lanicci, J.M., T.D. Allison, and H.E. Fuelberg, 2017: Numerical modeling of a heavy rainfall event in present and future climates. 29th Conference on Climate Variability and Change (American Meteorological Society), 22–26 January 2017, Seattle, WA.