Anomalous number of heavy
precipitation days for 2017 (left) and maximum daily precipitation for 2017 (right) both relative to the annual value for the period 1981 - 2010.
I present a graph from NOAA of change in average global temperature from 1880 to today and then show the graph of the U.S. increase in
heavy precipitation days from 1950 to today.
Their projections show an increase of about 35 % in days on which atmospheric rivers make landfall and an increase of about 28 % in extreme
precipitation days by the end of the 21st century.
Research indicates Western North America and Canada can expect a 28 percent increase in the number of
extreme precipitation days, thanks to global climate warming.
This figure shows on the left) coastal (blue) and inland (green) separation of USHCN (United States Historical Climatological Network) stations, and right) climatology of the associated precipitation frequency, daily intensity, and total precipitation by month, separated into
all precipitation days in the upper panels, and extreme (99th percentile) precipitation only in the lower panels.
The figure shows the spatial distribution of stations and the seasonal cycles, with results for
all precipitation days included for comparison with extremes.