Impacts of an Atmospheric River in the Morro Bay Wind Energy Area

The Morro Bay Wind Energy Area is one of two areas off the coast of California where offshore wind energy leases have been auctioned and awarded. In addition to the frequent occurrence of low-level jets and shallow marine atmospheric boundary layers (ABLs) off the California coast, understanding the potential impacts of extreme weather events are of keen interest to offshore wind developers. A relatively common type of extreme weather phenomena impacting this region are atmospheric rivers (ARs), which typically impact this region up to a few times per year. In this study we use high-resolution (1-km grid spacing) simulations from the WRF model, both independently and coupled with the WaveWatch III wave model, to simulate a moderate AR that impacted the Morro Bay Wind Energy Area in late January 2021. We also assess the sensitivity of model results for this AR to the choice of ABL scheme in WRF. Analysis of the winds, shear, veer, and precipitation intensity in the rotor layer in this area are performed, as is the impact of including a coupled wave model on these conditions that are relevant for offshore wind turbines. Validation of the WRF simulations are performed against the DOE-operated lidar buoy that was on a ~1-year deployment to the Morro Bay Wind Energy Area during this time, as well as a permanent National Data Buoy Center buoy that measures wave and near-surface atmospheric variables.