Public Information Statement
Issued by NWS Sterling, VA

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000 NOUS41 KLWX 231322 PNSLWX DCZ001-MDZ013-VAZ053-054-231730- Public Information Statement National Weather Service Baltimore MD/Washington DC 922 AM EDT Thu Jun 23 2016 ...New Flood Inundation Mapping coming soon to a portion of the Potomac River... Note the date of this implementation has been delayed by one week. Further minor delays could occur. This statement will be re-issued if any changes to the date occur. Effective on or about the week of July 5, 2016 (exact date to be determined), the National Weather Service (NWS) will add three new flood inundation map libraries to the Advanced Hydrologic Prediction Service (AHPS) web portal for portions of the Potomac River. These are the first NWS inundation maps covering any portion of the states of Maryland or Virginia, or the District of Columbia. These inundation map libraries show extent and depth of a freshwater flood on the Potomac River from near Fletcher`s Cove in Northwest DC to the mouth of Broad Creek in Prince George`s County, Maryland, a distance of approximately 14 miles. Backwater flooding of tributaries by the Potomac is also represented within this reach, including on Cameron Run, Oxon Run, Four Mile Run, and the Anacostia River. Each inundation library is associated with a NWS river forecast point, and extends north and south of each location. They will be available for the following forecast locations: * Potomac River at Georgetown/Wisconsin Avenue (GTND2) * Washington Channel at DC Southwest Waterfront (WASD2) * Potomac River at Alexandria (AXTV2) For additional details on these map domains, visit Inundation maps provide information on the spatial extent and depth of flood waters in the vicinity of these forecast points. Users will be able to display flood inundation maps for various levels ranging from minor flooding to well above the largest observed flood. An option is also available to display the map most closely related to the current forecast. Flood inundation maps, combined with river observations and NWS forecasts, enhance the communication of flood risk, provide users with additional information to better mitigate the impacts of flooding, and build more resilient communities. These flood inundation maps and associated geospatial data (shapefiles) will be available on or about the week of July 5, 2016 (exact date to be determined) through the AHPS portal at: A users guide for the flood inundation map web interface is available at: de.pdf These inundation maps were developed as an interagency project of the District of Columbia Silver Jackets team, made up of the Philadelphia and Baltimore Districts of the U.S. Army Corps of Engineers, the United States Geological Survey (USGS), the National Weather Service (NWS), the National Park Service, the D.C. Department of Energy and the Environment (DOEE), the National Capital Planning Commission (NCPC), and representatives from Arlington, Fairfax, and Prince George`s Counties, and the City of Alexandria. The maps are being made available online thanks to funding from D.C. DOEE and the City of Alexandria. This same project also created tidal inundation maps covering the same area. A subset of these tidal maps will be available on the AHPS portal linked above. The full suite of tidal maps will be made available on a separate site; links to all the web map locations will be appended to an updated version of this statement closer to the launch date. For additional information on this new service, please visit: If you have further questions, please contact: Jason Elliott National Weather Service Baltimore/Washington Senior Service Hydrologist Email: Phone: 703-996-2234 $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.