The continued redevelopment of heat watch-warning systems for cities and regions across the US has taken advantage of web technology to facilitate all aspects of the forecasting of oppressive heat. These systems have been designed using a series of UNIX-run scripts and FORTRAN programs to input forecast data real-time and output the forecast mortality information to a password-protected webpage.

The input of forecast data includes two different aspects– the input of the initial forecast data, and how to handle any updates to the forecast. With the switch to Point Forecast Matrices (PFM) by all NWS offices, both of these are now more easily accomplished, as forecast data are in a consistent, digital form. The heat warning systems are designed to search for updated PFM products every 10 minutes during the normal forecast cycle.

The output of the data varies according to whether forecasts are provided for an individual city or an entire region. These forecasts are password-protected so that only weather service office personnel and local authorized agencies may view the output.