89th American Meteorological Society Annual Meeting

Thursday, 15 January 2009: 12:00 PM
National Weather Service river flood warning verification
Room 127B (Phoenix Convention Center)
Mary G. Mullusky, NOAA/NWS, Silver Spring, MD; and E. Wells, T. Helble, and T. Graziano
The National Weather Service (NWS) provides critical hydrologic information to the public in the form of river flood warning products at over 4000 forecast points nationwide. These products provide forecasts of the timing and severity of river flood events. In an effort to improve the river flood warning program and provide performance indicators, a national river flood warning verification system is currently being developed. This river flood warning verification system will provide meaningful information on water courses ranging in size from small tributary streams and rivers to large main-stem rivers. Additionally, the system will be able to present results in the same framework as existing NWS severe weather and flash flood verification information. The system will provide statistics on river flood warning lead time, lead time error, probability of detection, false alarm ratio, and critical success index. Verification statistics will be stratified by time (1-day, multiple days, 1 month, multiple months or yearly), by locations (forecast point, groupings of forecast points, political boundaries, and nationally), and typical river response time (fast responding, intermediate responding, and slow responding). The NWS has been archiving river flood warning products since October 1, 2007. The national river flood warning verification system and the results from the 2008 water year will be presented.

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