New Precipitation Projections for the Pacific Northwest

New Precipitation

Projections for the Pacific Northwest

Photo: Kitsap Sun

Guillaume MaugerUW 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

More rain, NOT bigger storms

2080s1980s

No change in Winds

https://twitter.com/LigaDos32

Model Performance

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: 2030s1-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 MaugerUW Climate Impacts Groupcig.uw.edugmauger@uw.edu(206) 685-0317

Victoria Pinheiro, UW

https://cig.uw.edu/our-work/applied-research/heavy-precip-and-stormwater/

Substantial Warming, Variable Rainfall

Results from StatisticalDownscaling

Warm BasinsCold Basins

Salathé et al 2014

It matters how you do it.

2040s, A1B

Warm BasinsCold 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”