A real-time photochemical air quality forecast system has been implemented for the Puget Sound area of the Pacific Northwest as part of AIRPACT (Air Indicator Report for Public Awareness and Community Tracking), an EPA sponsored EMPACT project. This forecast system is based upon daily numerical weather forecasts from the Mesoscale Meteorological Model Version 5 (MM5) coupled to automated operation of the CALMET/CALGRID photochemical grid modeling pair. Hourly forecasts of ozone and other pollutant concentrations are produced for urban Seattle and its environs with a gridded domain measuring 62 (E-W) x 67 (N-S) cells (4 km x 4 km per cell) with 13 vertical layers of variable spacing. Detailed gridded emission inventories adjusted for time of day, day of the week, month, and gridded ambient temperatures are used as inputs to the modeling system. The forecast system includes acquisition of real-time pollutant observation data and automated evaluation of forecast accuracy. Forecasts are provided via the web on a daily basis. In this paper, the details of the forecast system are described and results from selected forecast periods are presented.