SR/HSD-96-6 10-1-96

Technical Attachment


Robert J. Corby, DOH
WGRFC Fort Worth, Texas

The West Gulf River Forecast Center (WGRFC) has developed an Online Information System for dissemination of real-time hydrometeorological information. This is a subscriber service which was developed to address the need for water control agencies to access a wide array of NWS public products, as well as some hydrometeorological data considered internal to the NWS that is not disseminated to the general public. This system was designed to allow these agencies quick and easy access to both text and graphical data utilizing a remote personal computer and a simple graphical user interface that links via a dial-up phone line to the data server maintained at WGRFC.

System Server

The data server for the Service Package resides at the WGRFC, and is accessible through dialup modems. The server consists of a Pentium PC equipped with an 8-port serial board and a LINUX operating system. The server runs two primary software packages, PPPD and HTTPD. The PPPD program allows remote computers to communicate with the server using TCP/IP communications protocol. The HTTPD program provides the necessary menus to access different types of data and serves text files and graphic images to the remote computer.

Remote System

A remote system, which is required by a water control agency to access the NWS data, consists basically of a personal computer and a modem, and can be located anywhere with phone-line access. The only software required on the remote system is a point-to-point protocol (PPP) dialup networking package and a hypertext markup language (HTML) browser. These packages are commercially available for most hardware platforms and operating systems. Both software packages are available from Microsoft for the Windows 95 operating system at no additional cost. The suggested configuration for a remote system is:

System Interface

The system interface consists of user-friendly menus in a "point and click" environment and can be tailored to meet the needs of any water control entity. Once connected, the user is guided through customized menus (Fig. 1) to various products which can be displayed, or saved locally.

Fig. 1. Customized Menu

Guadalupe Basin Main Menu

Menu Options

Available Products

Hydrograph Plots. The WGRFC forecasts river stages for approximately 500 forecast points throughout the area. River systems are modeled using the National Weather Service River Forecast System (NWSRFS) hydrologic forecast model on a six hour time interval. Each weekday morning, upon completion of the 12Z model run and evaluation, the observed and forecasted hydrographs for NWS forecast points, as well as non-forecast model support locations, are converted to graphic images and made available to the data server (Fig. 2). Additional forecasts are made on weekends and at synoptic times other than 12Z when hydrologic conditions warrant.

Stage III Plots. Every hour, the WGRFC mosaics the WSR-88D radar estimated precipitation from 22 radars which cover the area of responsibility. The radar estimated data is combined with "ground truth" from automated reporting rain gages to create the best estimate of hourly gridded precipitation, using the NWS application "Stage III". Graphic images of the hourly Stage III analysis for the entire WGRFC area are available through the Service Package (Fig. 3).

Quantitative Precipitation Forecasts (QPF). Every 12 hours, the WGRFC receives precipitation forecasts from the Weather Forecast Offices (WFOs) for 24 hours into the future. The WGRFC mosaics the estimates, and produces a QPF for the entire domain. The graphic images of QPF are then posted onto the Service Package server.

Stream Gage Data. Stream gages and lake elevations are reported to the WGRFC from a wide variety of sources. Data sources include cooperative observers, satellite telemetered data, telephone telemetered data, and data from local ALERT systems. This data is decoded as it comes into the forecast system and is posted to a database, where it is made available in text format through the Service Package.

AFOS Products. Text products received from AFOS are available as they are received on the network. The Service Package provides access to current products which are of interest to local water control entities. AFOS products available include:

Flood Statements and Warnings

Flash Flood Watches and Warnings

Flash Flood Guidance Products

Hydrometeorological Discussions

Current and Extended Weather Forecasts

Severe Weather Watches and Warnings

Rainfall and Gage Height Observations

Tropical Weather (hurricane) Products

User Response

Modernization has brought many new capabilities to the River Forecast Centers. WGRFC has found a unique way of sharing some of this new information with its water management cooperators. River authorities and other water management agencies in and around Texas have already shown interest in the service with many already online.