New
Precipitation
Projections for
the Pacific
Northwest
Photo: Kitsap Sun
Guillaume Mauger
UW Climate Impacts Group
Warner, Mass, Salathé, J Hydromet, 2014
Global models
project an increase
in heavy rains
Heaviest rain events are
projected to become +22%
more intense* (range: +5 to
+34%) by the 2080s.
* Top 1% of daily rainfall totals
in western WA & OR
2080s
1980s
More Water Vapor
More rain, NOT bigger storms
2080s
1980s
No change in Winds
https://twitter.com/LigaDos32
Model Performance
Two slides:
(1) showing correlation / lack thereof + comparison w other datasets,
(2) showing maps of biases
WSU Puyallup AgWeatherNet Gauge
Model Performance:
Bias in Total Annual Precip
Model Performance:
Bias in Top 1% Daily Precip
Model Performance:
Bias in Top 1% Hourly Precip
https://twitter.com/LigaDos32
Findings: Change in Heavy Rains
Projected Changes for Sea-Tac: 2030s
Projected Changes for Sea-Tac: 2050s
Projected Changes for Sea-Tac: 2080s
Change in the 25-yr storm: 2030s
1-hour
24-hour
(Ensemble Average. Relative to 1970-2005)
1-hour
24-hour
Change in the 25-yr storm: 2050s
(Ensemble Average. Relative to 1970-2005)
1-hour
24-hour
Change in the 25-yr storm: 2080s
(Ensemble Average. Relative to 1970-2005)
Guillaume Mauger
UW Climate Impacts Group
cig.uw.edu
[email protected]
(206) 685-0317
Victoria Pinheiro, UW
https://cig.uw.edu/our-work/applied-
research/heavy-precip-and-stormwater/
Substantial Warming, Variable Rainfall
Results from Statistical
Downscaling
Warm Basins
Cold Basins
Salathé et al 2014
It matters how you do it.
2040s, A1B
Warm Basins
Cold Basins
Salathé et al 2014
Results from Dynamical
Downscaling
It matters how you do it.
2040s, A1B
How well do we know
our current risk?
“100-year event”