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Roderick A. Scofield

Abstract

This paper presents the NESDIS operational technique for estimating convective rainfall from GOES data. Estimates and 3-hour outlooks are computed on the Interactive Flash Flood Analyzer (IFFA) and transmitted via the Automation of Field Operations and Services (AFOS) computer systems to Weather Service Forecast Offices, Weather Service Offices, and River Forecast Centers. The technique consists of two steps: (1) locating the active portion of the convective system and (2) computing half-hourly rainfall estimates based on cloud-top temperature and cloud growth or divergence aloft, overshooting tops, mergers, saturated environment (stationary storms), and a moisture correction factor. A warm-top modification is used for cloud tops warmer than −62°C. Three-hour outlooks are based on persistence and extrapolation and trend and expectancy guidelines. Verification results show the average error of the rainfall estimates for a storm total precipitation event is about30%.

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Roderick A. Scofield and Robert J. Kuligowski

Abstract

Flash floods are among the most devastating natural weather hazards in the United States, causing an average of more than 225 deaths and $4 billion in property damage annually. As a result, prediction of flash floods in an accurate and timely fashion is one of the most important challenges in weather prediction. Data from geostationary and polar-orbiting satellites are significant sources of information for the diagnosis and prediction of heavy precipitation and flash floods. Geostationary satellites are especially important for their unique ability simultaneously to observe the atmosphere and its cloud cover from the global scale down to the storm scale at high resolution in both time (every 15 min) and space (1–4 km). This capability makes geostationary satellite data ideally suited for estimating and predicting heavy precipitation, especially during flash-flood events. Presented in this paper are current and future efforts in the National Environmental Satellite, Data, and Information Service that support National Weather Service River Forecast Centers and Weather Forecast Offices during extreme-precipitation events.

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