LANDFALLING TROPICAL CYCLONES - FORECAST PROBLEMS AND ASSOCIATED RESEARCH OPPORTUNITIES

The Fifth Prospectus Development Team of the U.S. Weather Research Pro gram was charged to identify and delineate emerging research opportuni ties relevant to the prediction of local weather, flooding, and coasta l ocean currents associated with landfalling U.S. hurricanes specifica lly, and tropical cyclones in general. Central to this theme are basic and applied research topics, including rapid intensity change, initia lization of and parameterization in dynamical models, coupling of atmo spheric and oceanic models, quantitative use of satellite information, and mobile observing strategies to acquire observations to evaluate a nd validate predictive models. To improve the necessary understanding of physical processes and provide the initial conditions for realistic predictions, a focused, comprehensive mobile observing system in a tr anslating storm-coordinate system is required. Given the development o f proven instrumentation and improvement of existing systems, three-di mensional atmospheric and oceanic datasets need to be acquired wheneve r major hurricanes threaten the United States. The spatial context of these focused three-dimensional datasets over the storm scales is prov ided by satellites, aircraft, expendable probes released from aircraft , and coastal (both fixed and mobile), moored, and drifting surface pl atforms. To take full advantage of these new observations, techniques need to be developed to objectively analyze these observations, and in itialize models aimed at improving prediction of hurricane track and i ntensity from global-scale to mesoscale dynamical models. Multinested models allow prediction of all scales from the global, which determine longterm hurricane motion to the convective scale, which affect inten sity. Development of an integrated analysis and model forecast system optimizing the use of three-dimensional observations and providing the necessary forecast skill on all relevant spatial scales is required. Detailed diagnostic analyses of these datasets will lead to improved u nderstanding of the physical processes of hurricane motion, intensity change, the atmospheric and oceanic boundary layers, and the air-sea c oupling mechanisms. The ultimate aim of this effort is the constructio n of real-time analyses of storm surge, winds, and rain, prior to and during landfall, to improve warnings and provide local officials with the comprehensive information required for recovery efforts in the har dest hit areas as quickly as possible.