Following Congressional direction, NOAA's National Weather Service (NWS) is implementing a National Air Quality Forecast Capability, with an initial domain over Northeastern US. The capability is based on partnering with EPA, who provides national emissions inventory data to NOAA for the forecast model as well as near real-time access to ozone air quality monitoring data for verification. The initial forecast capability links an adaptation of the Community Multiscale Air Quality (CMAQ) model, developed by NOAA/EPA researchers, with the Eta-12 mesoscale weather prediction model, running operationally at NWS' National Centers for Environmental Prediction. NWS issues gridded numerical Air Quality predictions as forecast guidance twice daily, with hour-by-hour predictions of both 1-hr and 8-hr averaged ground-level ozone concentration. EPA presents the forecast guidance in terms of the health-based Air Quality Index.

During the summers of 2003 and 2004, NWS integrated CMAQ modules into its operational supercomputing environment for real-time testing of the initial air quality forecast capability, for planned operational deployment over Northeastern United States in September, 2004. A focus group of state and local Air Quality forecasters provided feedback to developers on real-time testing, with special emphasis on community-specific performance and product utility. Verification results for 2003 demonstrate skill in predicting ozone exceedance levels. 2003 tests also demonstrate, for conditions generally cooler and rainier than average, a consistent bias in overpredicting ozone concentrations. To address the overprediction bias, model system improvements to Eta-CMAQ linkage, lateral ozone boundary conditions, updated emissions inventory data, and vertical mixing parameterziations have been tested and implemented in experimental forecast guidance issued in 2004. The improvements have significantly reduced the bias in predicted ozone concentrations.

The NOAA and EPA guidance will serve as a standard tool, ultimately Nationwide, for public and private, state and local forecasters who provide tailored air quality forecasts for their communities, and EPA who provides interpretive air quality health indices/alerts.