Investigation of the Structure of Natural Orographic Clouds Embedded Within Atmospheric River Type Flow over the Payette Mountains of Idaho
The Seeded and Natural Orographic Wintertime clouds: the Idaho Experiment (SNOWIE) field campaign operated from January 7, 2017 – March 17, 2017, in the Payette Basin just northeast of Boise, ID. The goal of this campaign was to use radar and in-situ measurements to observe seeded and natural orographic clouds to prove the efficacy of orographic cloud seeding over the Payette Basin. One of the platforms used was the Wyoming King Air aircraft equipped with the Wyoming Cloud Radar (WCR), a 3 mm wavelength cloud radar, which flew through, and collected data on orographic clouds to obtain fields of reflectivity and radial velocity. Within these orographic clouds, knowing the location and amount of supercooled liquid water (SLW) is vital to the success of cloud seeding missions. Past research has identified several common structural aspects of orographic clouds in which SLW is frequently present. Using the WCR observations, supplemented by simulations using the Weather Research and Forecasting model, these structural aspects were investigated within atmospheric river type flow, which was the dominant synoptic weather pattern during SNOWIE Intensive Operating Periods. Additionally, a trajectory analysis was conducted to understand the source regions for the different layers observed in these orographic cloud systems.