Climate and Energy Action Plan (CEAP)

CLIMATE TRENDS & PRO JECTIONS | CITY OF ASHLAND, OREGON | FINAL REPORT | 7 Overview Temperature in Ashland increased significantly over the historical period while trends in precipitation we re less clear. All models agree that temperature will continue to increase in the future. However, fut ure projections of annual precipitation have less confidence: some models project increases while other models project decreases. Because precipitation is highly variable from year to year, the future direction of change in precipitation and precipitation -derived metrics is less certain than for temperature metrics. Measures of extreme precipitation and extreme te mperature were also analyzed . In general, warm temperature extremes are projected to increase . Extreme cold measures ar e projected to change in a manner consistent with overall warming : increases in the coldest night of the year and decreases in the number of days below freezing . In terms of possible increases or decreases in precipitation e xtremes , the sign of change depend ed on the model. Snow water equivalent (SWE) in the Rogue Basin —a metric that indicates the amount of water contained within the snowpack —decreased over the historical period. SWE is influenced by both temperature and prec ipitation changes, but the influence of temperature dominates in future projections. All models agree that SWE will decrease in the future. Table 1 lists all of the variables that are reported in this document. Table 1. Description of variables. Variable Description Average Temperature Daily mean temperature averaged over the year Hottest Day of Year Yearly maximum of daily maximum temperature Warm Spell Duration Index Number of days in the year in which maximum temperature is of the highest 10% for that day in the historical baseline Days above 100°F Number of days in the year with maximum temperature equal to or greater than 100°F Days above 110°F Number of days in the year with maximum temperature eq ual to or greater than 110°F Nights above 60°F Number of days in the year with minimum temperature equal to or greater than 60°F Heating Degree Days Annual accumulation of days and degrees below 65°F Cooling Degree Days Annual accumulation of days and d egrees above 65°F Coldest Night of Year Yearly minimum of daily minimum temperature Frost Days Number of days in a year with minimum temperature below 32°F Precipitation Total water year precipitation Extreme Precipitation Frequency Number of days in t he year with precipitation equal to or greater than 20 mm (~3/4”) Consecutive Dry Days Maximum run in a year of consecutive days with less than 1 mm precipitation Extreme Precipitation Amount Total annual precipitation on days with greater than 95th perc entile precipitation Snow Water Equivalent The amount of water contained within the snowpack Table 2 presents the multi -model mean change and the range of changes across all models for each metric considered in Table 1 for the 2050s (2040 -2069 average) and 2080s (2070 -2099 average) under the low