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University of Washington: "Improvement of mesoscale forecasting in the Pacific Northwest"

Final Report

The basic goal of this Cooperative Project is to enhance operational forecasting in the Pacific Northwest by conducting joint mesoscale research efforts with the NWS, promoting a broad range of interactions with the Seattle WSFO, and by facilitating the operational acquisition of regional observations. Projects undertaken in support of this objective include: 1) creation of a mesoscale database by combining and decoding the data collected by the many telemetered real-time observing networks of the region; 2) completion of an intensive study of the mesoscale and synoptic evolution of western Washington snowstorms and a second study of strong winds observed near Anacortes and Guemes Island; 3) establishment and maintenance of digital communication between the Seattle WSFO and the University and exchanging analysis and display software such as GEMPACK; 4) development of software for aiding forecasting and the analysis of local observations (for example, decoding and plotting software, as well as pressure gradient and time series analysis software); and 5) study of the pressure patterns associated with the Puget Sound Convergence Zone event, the most important forecasting problem in western Washington. A network of microbarographs collected data as part of this study over the Puget Sound lowlands for a six-month period; data from the instruments are currently being analyzed.

In addition, the participants have developed an analog forecasting/diagnostic package which finds analogs for the forecast fields (from the Aviation/MRF Model) using 40 years of "weather maps" on the NMC Grid Point CD-ROM. After the best matches have been determined, the weather on those days in the area can be found from past records and used as an aid for making the next day's forecast. This technique appears to be very promising and could easily be adapted for use in other regions of the country. An evaluation of high-resolution numerical modeling techniques for regional forecasting has also been performed. Several successful runs of the Penn State/NCAR mesoscale model (MM4) have been made for a Puget Sound Convergence Zone event.

Other activities not directly funded by COMET, but indicative of the level of cooperation between the participants include joint hosting by the university and NWS of annual workshops on the meteorology of the Pacific Northwest, organization and completion of the COAST field experiment to study the interaction of synoptic-scale flow with the coastal topography of the Pacific Northwest, and joint efforts to acquire a 915 Mhz profiler/RASS.