Generalized Analysis of Orographically Modified Winds and Precipitation Observed by Airborne Doppler Radar During Phases 1 & 2 of Coast
WASHINGTON UNIV SEATTLE JOINT INST FOR STUDY OF ATMOSPHERE AND OCEAN
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LONG TERM GOALS. Accurate short-range forecasts approximately 0-48 h lead of significant mesoscale weather disturbances, especially high winds and heavy precipitation, that can accompany landfalling cool-season frontal systems and intervening periods of steadier flow impinging upon steep coastal terrain. OBJECTIVES. The purpose of this research is to obtain a quantitative, dynamically-based understanding of the airflow and precipitation patterns associated with both oceanic frontal systems and steady onshore flows as they encounter steep coastal terrain. While the capability of mesoscale numerical forecast models to address this problem has not yet been fully tested, such models offer great potential for capitalizing upon this improved understanding if critical processes are identified and appropriate model physicsparameterizations are put into place. Emphasis is thus placed upon analysis of specialized observations from multiple storm events to identify repeatable mesoscale kinematic and related precipitation patterns and subsequently relate their occurrence to features of the evolving large-scale and variations in underlying coastal orography. Through cooperation with other ONR-supported PIs, these analyses are used to validate, test and improve mesoscale models. Of particular interest are those processes leading to development of high winds, restricted ceilingvisibility and heavy precipitation over coastal waters, as well as modulation of airflow and precipitation over the adjacent sloped terrain. Data obtained through observational efforts are also evaluated critically to focus hypotheses and improve observational strategies applied in subsequent field programs.