Advanced Hydrologic Prediction Services for Water Resources and Emergency Management


Current water resources forecasting techniques make limited use of growing skill in short- to long-range weather and climate forecasts. The National Weather Service's planned Advanced Hydrologic Prediction Services (AHPS) will take advantage of these new skills. Once implemented, AHPS will produce hydrologic forecasts with lead times of a few days to several months (see accompanying graphic). It will provide river forecasts that not only account for precipitation already on the ground but that also will probabilistically account for estimates of future precipitation. This coupled prediction service will greatly improve the Nation's capability to take timely and effective actions that will significantly mitigate the impact of major floods and droughts. The system will also provide better overall information for use in managing competing water demands for irrigation, fisheries, hydropower and other purposes.

Picture banner for Advanced Hydrologic Prediction Services

Figure 1. Advanced Hydrologic Prediction Services

The AHPS builds on partnerships with other water cooperators (federal, state, multi state, quasi-governmental, and private sector organizations) and on existing National Weather Service (NWS) infrastructure, including the 13 River Forecast Centers (RFCs) and the NWS River Forecast System (NWSRFS) , a very large software system used by RFC hydrologists to produce forecasts of time series of discharges or stages at approximately 4,000 locations along the nation's rivers. It will take advantage of the NWS Modernization program which is providing NWS RFCs with  Advanced Weather Interactive Processing System (AWIPS) equipment, a powerful suite of networked computer workstations with graphic capabilities. The modernization is also providing national coverage with approximately 140 WSR-88D Doppler radars which produce multisensor, high resolution (space and time) precipitation estimates utilizing gauge precipitation observations from networks such as the new Automated Surface Observing System (ASOS) . The precipitation processing algorithms, using WSR-88D data, are being enhanced to account for bright band effects and to improve the rain gauge bias adjustment, while future enhancements will address orographic effects and snow accumulation.

A critical component of the AHPS is the provision of advanced technical capabilities. These advancements provide for:

The advanced hydrometeorologic/hydrologic modeling of AHPS, along with NWS advances in weather and climate forecasting, will greatly improve NOAA's capability to provide more timely and accurate river forecasts. Therefore, AHPS will greatly enhance NOAA's national responsibility to provide river and flood forecasts and warnings for the protection of life and property and for the economic and environmental well-being of the nation. For these multiple uses, NWS will provide advanced forecast products through the AHPS which meet multiple objectives including:

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