Forecasting in the USA

1. Forecasting in the USA • The National Weather Service River Forecast System (NWSRFS), developed since the 1970s, has been the heart of the NWS hydrologic forecasting system. • NWSRFS was optimized for the computers of that era, which were slow and had very little storage. NWSRFS is very fast and the disk storage very compact. • But it is based on 1970s computer science languages and concepts, which makes it very difficult to maintain. • NWS adopted Deltares (formerly Delft Hydraulics Lab) Flood Early Warning System (FEWS), as its basis for the Community Hydrologic Prediction System (CHPS), to allow a flexible environment for operations, the ability to introduce research performed by third parties into NWS operations in a straightforward manner, and facilitate researchers worldwide easy access to NWS observational databases.

2. CHPS Characteristics • Uses gridded environmental forcings. • Precipitation. • Temperature. • Freezing level. • Potential evapotranspiration. • Uses a sequence of models. • Many components have been migrated from NWSRFS. • HEC-ResSim added for reservoir operation simulation. • HEC-RAS added for hydraulic routing. • Supports ensemble simulations. • Provides a variety of notification options. Example Ensemble Forecast

3. WIS-WIGOS • The United States collectively with other RA-IV Members have identified WIS and WIGOS as key priorities for the Region. • The RA-IV Management Group set up a Task Team to coordinate implementation activities for WIS and WIGOS. • RA-IV WIGOS implementation will cover the full range of observation requirements but will place priority on exchange of RADAR data early in the process of implementation recognizing that RADAR data supports tropical cyclone and hydrological forecasting including flash flood and storm surge. • Within RA-IV, NOAA/NWS has begun development of a WIS Discovery, Access and Retrieval (DAR) service that will be a part of a Washington Global Information System Center (GISC), a central WIS hub. • RA-IV Members will provide information through other WIS data centers within the Region to meet collective requirements including those for Flash Flood Forecasting.

4. Multi-Hazard Warning • The Global Flash-Flood Guidance System is a project with WMO to assist countries in issuing effective warnings. • Meteorological data is used in combination with a soil moisture model to predict runoff potential. • The system provides data and information to NMH Services to develop flash flood alerts and warnings. • Under this project, system implementations are planned for Southern Africa and the Black Sea/Middle East regions. Example FFG System Products

5. Capacity Building • Capacity building is a cross-cutting theme that involves all mission areas relevant to weather, water, and climate forecasts and warnings. • Promotes the establishment of observing networks which leads to collaboration through data sharing. • Establishes centers to collect, process, and share data. • Promotes standardization in observing equipment, data formats, forecasting methods, and service delivery. • Encourages new research and training in hydrometeorology to assist in the international collaboration. Ethiopia, 2007 Kenya, 2007