Mesoscale Nocturnal Wind Maxima Over the Pacific Northwest in Summer

During the summer, strong surface heating and land-water contrasts combine with the complex topography of the Pacific Northwest to create diurnal circulations that affect not only wind speed and direction, but also cloudiness, temperature, and moisture. Though observational studies and modeling case studies have described some of these circulations, advances in high-resolution numerical modeling allow for a more comprehensive, three-dimensional examination of these important features. Summertime composites of GFS model output were used to initialize and provide boundary conditions to a WRF model run. To ensure the realism of the simulation, it was compared to observations on a collection of days representing typical summer conditions. Generally, it was found that the simulated diurnal wind, relative humidity, and temperature were close to observations. In this talk, the results of this run will be used to describe the diurnal, three-dimensional circulations over the region, as well as their implications for important meteorological variables. In particular, localized nocturnal low-level wind maxima will be described, including one over the northern Willamette Valley and another over the high plateau of eastern Oregon.