The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) Western Region Headquarters and NOAA/NWS Los Angeles/Oxnard Weather Forecast Office (WFO) continues to explore GIS applications to enhance internal forecast operations while providing digital forecast information for its users in a GIS compatible format. Previous work included collaboration with the NOAA Coastal Services Center to implement a layered visualization tool allowing users to view weather forecast and hazards data across a southern California domain, simply using an Internet browser. Recent work has expanded the domain of this Weather and Hazards Data Viewer from the previous extent covering southern California, to its current extent encompassing the continental United States. In addition to the domain expansion, an open source GIS software solution has been implemented to replace the previous ESRI ArcIMS application. This change to open source was primarily driven by the need to use a more cost-effective software solution in an increasingly challenging budget environment.

The Weather and Hazards Data Viewer provides access to the NWS National Digital Forecast Database (NDFD), which consists of gridded (5 kilometer by 5 kilometer) forecasts of sensible weather elements. The viewer currently provides access to maximum and minimum temperature, surface wind speed, direction, and gust, relative humidity, precipitation amount, and significant wave height. The user can view a static image of the weather forecast at a given time or can loop or animate a forecast element to get a sense of the forecast changes over a period of time. Future enhancement of the weather and hazards viewer will include the addition of snow amount, heat index, wind chill, weather (wx), and probability of precipitation (PoP).

Additional hazards such as current and historic fire perimeters, recent earthquakes, and tsunami inundation layers are also available for viewing. Accompanying weather forecast elements and select hazards is the ability to view current radar and satellite images. Looping of radar images is available in the tool to enhance the usability.

To make use of this tool, users access a simple on-line mapping application that allows visualization of the weather forecasts and associated hazards through an Internet web browser. The tool also includes a hyperlink providing access to GIS shapefiles of the same NDFD weather forecast elements available in the viewer. The weather forecast shapefile service, at this time, is only available for the western half of the United States and is available at a 2.5 kilometer by 2.5 kilometer resolution.

This paper will discuss in further detail the enhancement and expansion of the Weather Forecasts and Hazards Data Viewer, and implementation of an open source GIS software solution in place of ESRI's ArcIMS.