SR/SSD 97-53


Technical Attachment

Summary of National QPE Workshop, Boulder, CO

November 18-20, 1997

Tom Graziano

National Weather Service Office of Meteorology

In late November the NWSH Office of Meteorology conducted a three-day National Quantitative Precipitation Estimation (QPE) Workshop at the COMET facility in Boulder, Colorado. QPE requirements and applications, and supporting applied research were reviewed by about forty participants, including representatives from the following organizations:

- NWS Headquarters (OM, OH, OSD/TDL, OSO)


- The six NWS regions


- NCAR (Research Applications Program/RAP)




During the discussions the participants:

A more comprehensive summary of the workshop, including a QPE implementation plan, will be developed over the next 90 days, but the following is a brief summary of results and conclusions that were arrived at during the workshop sessions.

With regard to the application of high resolution rainfall estimates, the operational assessment and forecasting of flash flooding conditions was the focus of considerable discussion. This discussion stemmed primarily from the following three presentations:

1. Areal Mean Basin Estimated Rainfall (AMBER) program (Bob Davis/WSFO Pittsburgh). AMBER is a software application which utilizes the 1 km x 1 deg Digital Hybrid Scan Reflectivity (DHR) product from the WSR-88D to compute radar rainfall estimates in flash flood watersheds every volume scan. A single rainfall estimate is computed for each 1 km range bin. All range bins whose center point falls in a particular stream watershed are averaged to compute the Average Basin Rainfall (ABR) for that watershed.

The small DHR rainfall grid enables AMBER to compute ABR in watersheds as small as a square mile in area. The likelihood of flooding is established by comparing the ABR with Flash Flood Guidance (FFG); that is, the ABR needed to bring a stream to bankfull. A full description of the history, functionality, and operational utility of the AMBER program can be found at:

2. WFO Hydrologic Forecast System (D.J. Seo/OH). The WFO Hydrologic Forecast System (WHFS) is a collection of many applications developed in the Hydrologic Research Lab (HRL) of the Office of Hydrology (OH) that support the hydrology program at a WFO. The broad spectrum of WHFS capabilities include applications for data collection and management, data display, hydrometeorologic modeling, and product management functions. The WHFS is currently deployed and being tested at a number of WFOs.

The hydrometeorologic modeling component of WHFS includes:

A full description of WHFS can be found at:

3. System for Convection Analysis and Nowcasting/SCAN (Stephan Smith/OSD). SCAN is a collaborative effort among the NWS, NSSL and the NCAR. SCAN focuses on improving the accuracy and timeliness of severe weather warnings through the development of automated warning guidance. The goals of SCAN are:

A complete description of SCAN can be found at:

Regional Scientific Services Division (SSD) chiefs and other participants were impressed by the AMBER flash flood application and expressed a desire to see similar functionality included in future releases/upgrades of the hydrometeorologic modeling component of WHFS. Although the flash flood modeling component of represents only one part of a broad spectrum of robust WHFS applications, this component was recognized as critical given the significant economic and human impacts of flash flooding.

There was also considerable interest in expanding the Pittsburgh testing to additional locations, where flash flooding is a critical problem, prior to AWIPS. This might be done by using existing RIDDS/WDSS hardware, or by exploring other means which would allow offices to tap the DHR product from the WSR-88D RPG.

Participants were also very interested in SCAN, especially its potential to improve the watch/warning capability at the WFO, its potential role as a vehicle for the implementation of future nationally-and locally-developed applications within AWIPS, and its relationship to WHFS. In response to this interest it was decided at the QPE workshop that national program managers, developers and regional representatives should assemble to discuss the future development and implementation of hydrometeorological applications within AWIPS, and their integration/coordination with the rapidly evolving SCAN effort. Plans for such a meeting will be developed.