The NOAA/National Weather Service (NWS) Los Angeles/Oxnard weather forecast office has been applying numerous GIS applications to enhance local internal forecast operations, and to meet the growing customer and partner demand for forecast products in a GIS compatible format. Internal forecast operations have been enhanced through the addition of numerous mission critical data layers into the local Advanced Weather Interactive Processing System (AWIPS) as well as into Hydroview, the operational hydrologic monitoring system. One of these mission critical data layers is recent wildfire perimeters. Southern California is very susceptible to wildfires that not only pose a threat when they are burning, but also increase the future risk for flash flooding and debris flows within and downstream of these areas during heavy rains. Burn area perimeter shapefiles are added as overlay maps within AWIPS and Hydroview to allow forecast personnel to view the location of past burn areas in relation to active weather systems and heavy rainfall. This has resulted in improved forecaster situational awareness, which then translates into improved service. Additionally, a GIS based flash flood potential index (FFPI) application – developed by the Colorado Basin River Forecast Center (CBRFC) – is being applied to flash flood monitoring and prediction at the Los Angeles/Oxnard weather forecast office. Use of an open source GIS software solution allows for operational use of the FFPI application at six separate forecast desks.

In response to local customer demand for forecast products in a GIS compatible format, the Los Angeles/Oxnard weather forecast office is providing gridded weather forecast information to customers as GIS shapefiles. The National Digital Forecast Database (NDFD) is designed to provide access to weather forecasts in digital form. NWS customers can access these digital data, which are available in a GRIB2 format, via file transfer protocol (ftp), eXtensible Markup Language (XML), or a web browser. Free GRIB2 decoding software, called DeGRIB, is also available. Using a template application developed by the Medford Oregon weather forecast office, the Los Angeles/Oxnard weather forecast office implemented command line scripts that run the DeGRIB software to access local digital forecast datasets, then convert them into GIS compatible shapefiles. These shapefiles are then made available on a local office web page. Currently, maximum and minimum temperature, wind speed and direction, and relative humidity forecasts are being made available via this web page. Local customers can access these shapefiles for use within their own GIS systems. In summary, GIS has been incorporated into nearly every forecast program at the Los Angeles/Oxnard weather forecast office, with new and unique applications to enhance forecast operations and meet customer forecast needs continually being sought out and developed.

This paper will discuss in further detail GIS applications to enhance local internal forecast operations at the Los Angeles/Oxnard weather forecast office and GIS applications to meet the growing customer and partner demand for forecast products in a GIS compatible format. Example GIS applications and uses of the NDFD datasets by several local Southern California agencies will be presented and summarized.