Evolution of a Cold Front Encountering Steep Quasi-2D Terrain: Coordinated Aircraft Observations on 8-9 December 2001 during IMPROVE-2

Abstract Research aircraft observations from the 8–9 December 2001 case of the second phase of the Improvement of Microphysical Parameterization through Operational Verification Experiment (IMPROVE-2) describe the evolution of a wide cold-frontal rainband (WCFR) during its eastward advance from the Pacific coastline to a point 200 km inland over the Cascade Mountains of Oregon. This analysis has two objectives: first, to illustrate the rapid weakening of the circulation associated with a landfalling WCFR and the relationship of these changes to terrain-induced airflow modifications, and second, to quantify the degree to which this weakening impacted cloud microphysical properties such as liquid water content, ice particle concentrations, and precipitation rate. The kinematic structure of the WCFR is detailed using Doppler radar observations from a NOAA P-3 aircraft, while some concomitant cloud microphysical properties are documented using flight-level measurements from the University of Washington Convai...