Synoptic Control of Mesoscale Precipitating Systems in the Pacific Northwest

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

This research will examine the extent to which an adequate representation of flow features on the synoptic scale allows for the skillful simulation of mesoscale precipitating systems. The research will emphasize independent verification and rigorous hypothesis testing within a controlled setting in order to quantify the significance of the results. The focus of the research is on the specific problem of landfalling precipitating systems on the West Coast of United States. The Principal Investigators will explore a broad variety of landfalling systems that lead to significant rainfall in this region. The primary tools of the research will be an advanced mesoscale numerical model, NCEP and ECMWF reanalysis data sets, and independent precipitation measurements from all available surface sites in the Pacific coast states (Washington, Oregon and California). The role of lateral boundary conditions (LBC) will be explicitly accounted for by the study design and ongoing evaluation of study results will be used to control for biases that may be introduced by model physics limitations. Separating initial and boundary condition errors, LBC errors due to the placement of the boundaries of the nested grid model, and error by type of synoptic system will represent a significant advance in understanding of these weather systems. The results of this study will be of considerable interest to short term weather forecasting.