Landfalling Tropical Cyclones: Forecast Problems and Associated Research Opportunities

Abstract

The Fifth Prospectus Development Team of the U.S. Weather Research Program was charged to identify and delineate emerging research opportunities relevant to the prediction of local weather, flooding, and coastal ocean currentsassociated with landfalling U.S. hurricanes specifically, and tropical cyclones in general. Central to this theme are basicand applied research topics, including rapid intensity change, initialization of and parameterization in dynamical models, coupling of atmospheric and oceanic models, quantitative use of satellite information, and mobile observing strategies to acquire observations to evaluate and validate predictive models. To improve the necessary understanding ofphysical processes and provide the initial conditions for realistic predictions, a focused, comprehensive mobile observing system in a translating storm-coordinate system is required. Given the development of proven instrumentation andimprovement of existing systems, three-dimensional atmospheric and oceanic datasets need to be acquired whenevermajor hurricanes threaten the United States.The spatial context of these focused three-dimensional datasets over the storm scales is provided by satellites, aircraft, expendable probes released from aircraft, and coastal (both fixed and mobile), moored, and drifting surface platforms. To take full advantage of these new observations, techniques need to be developed to objectively analyze theseobservations, and initialize models aimed at improving prediction of hurricane track and intensity from global-scale tomesoscale dynamical models. Multinested models allow prediction of all scales from the global, which determine long-term hurricane motion to the convective scale, which affect intensity. Development of an integrated analysis and modelforecast system optimizing the use of three-dimensional observations and providing the necessary forecast skill on allrelevant spatial scales is required. Detailed diagnostic analyses of these datasets will lead to improved understanding ofthe physical processes of humcane motion, intensity change, the atmospheric and oceanic boundary layers, and the air-sea coupling mechanisms. The ultimate aim of this effort is the construction 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 informa-tion required for recovery efforts in the hardest hit areas as quickly as possible.