SWEX: Sundowner Winds Experiment

Summary

Downslope windstorms at the lee of the Santa Ynez Mountains (SYM) in Santa Barbara County are one of the most significant fire weather hazards affecting populated areas. These gusty winds known as Sundowner winds, peak from early evening to mid-morning. Modeling results show that the intensity and spatial variation of Sundowners are driven by a combination of dynamic and thermodynamic mechanisms that depend on the complex-terrain boundary layer dynamics, profiles of winds and stability. The main goal of this proposal is to improve the current understanding of the dynamics and predictability of downslope windstorms in coastal Santa Barbara County. This science proposal is in support of the proposal “Sundowner Winds Experiment” (SWEX) submitted to NCAR/LAOF. The three main scientific objectives are:

1. Investigate how boundary layer structure and dynamics spanning the SYM and Santa Ynez Valley influence Sundowner winds intensity, timing and geographic characteristics,

2. Examine mechanisms relating high amplitude mountain waves, critical layers, and surface wind intensity, and

3. Investigate how variations in boundary layer structure and tropospheric stability impact the predictability of Sundowner winds.