9714552 Elsberry The U.S. Weather Research Program (USWRP) is an interagency activity designed to perform and implement the research necessary to improve the delivery of weather services to the nation. Under this Program, the National Science Foundation, the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration and the Office of Naval Research are jointly evaluating and supporting research of high priority to the USWRP. The precedent circulations that contribute to the development of damaging weather systems over the western and mid-western U.S. often approach from the data-sparse region of the eastern Pacific. In many cases, these precedent circulations have small horizontal dimensions that are not well resolved by the existing upper-air sounding network. A special set of upper-air observing stations called the West- Coast Picket Fence was established to measure the circulations crossing the west coast of the U.S. during the Stormscale Operational and Research Meteorology- Fronts Experiment Systems Test (STORM-FEST) held from February to March 1992. In particular, three-hourly Picket Fence soundings were obtained from the combination of seven special and seven existing upper-air stations during four intensive observing periods. Analyses completed thus far demonstrate that the higher spatial resolution of the combined Picket-Fence sites with three hourly soundings better resolve the energy fluxes crossing the coast than the seven existing sites with the regular 1 2-hourly soundings. This Picket Fence is considered to be a prototype for a future system of ground-based remote sensors that might be deployed along the west coast that would monitor all circulations crossing the coast. One goal of the USWRP is to determine the "best practicable mix" of observations, data assimilation schemes, and forecast models that will yield cost- effective weather forecast improvements for operations beyond the year 2000. Crucial steps towards realizing this goal, and the associated goals of the North American Observing System (NAOS) Program include the development and evaluation of new data sources and observation strategies. We propose to evaluate the potential impact of a quasi-linear array of special observing sites along the west coast of the United States for the purpose of improving the downstream 0 - 2 day forecast accuracy over North American. Specifically, we propose to utilize the operational and special west coast Picket Fence data collected during STORM-FEST in tests with the National Centers for Environmental Prediction (NCEP) mesoscale data assimilation and modeling system to examine the impacts of the special data and new observing strategy on simulations of selected events during (the experiment ***
